The 100 most-cited articles in Inorganic Chemistry, 2021

Metal oxide materials that adopt the spinel crystal structure, such as metal ferrites (MFe 2 O 4 ), present tetrahedral (A) and octahedral [B] sublattice sites surrounded by oxygen anions that provide a relatively weak crystal-field splitting. The formula of a metal ferrite material is most precisely described as (M 1– x Fe x )[M x Fe 2– x ]O 4, where the parentheses and square brackets denote the tetrahedral and octahedral sites, respectively, and x is the inversion parameter quantifying the distribution of M 2+ and Fe 3+ cations among these sites. The electronic, magnetic, and optical properties of spinel ferrites all depend on the magnitude of x, which, in turn, depends on the relative sizes of the cations, their charge, and the relative crystal-field stabilization afforded by tetrahedral or octahedral coordination. Compared to bulk spinel ferrites, the large surface-area-to-volume ratio of spinel ferrite nanocrystals provides additional structural degrees of freedom that enable access to a broader range of x values. Achieving synthetic control over the degree of inversion in…

Luminescent metal–organic frameworks (LMOFs) as sensors showing highly efficient detection toward toxic heavy-metal ions are in high demand for human health and environmental protection. A novel nanocage-based N-rich LMOF ( LCU-103 ) has been constructed and characterized. It is a 2-fold interpenetrating structure built from N-rich {Zn 6 (dttz) 4 } nanocages extended by N-donor ligand Hdpa [H 3 dttz = 4,5-di(1 H -tetrazol-5-yl)-2 H -1,2,3-triazole; Hdpa = 4,4′-dipyridylamine]. Notably, LCU-103 contains abundant N functional sites anchoring on both the windows of nanocages and the inner channels of the framework that can interact with metal ions and then recognize them. As a result, it can serve as a luminescent sensing material for detecting trace amounts of Fe 3+ and Cu 2+ ions with low limits of detection (LODs) of 1.45 and 1.66 μM, respectively, through a luminescent quenching mechanism. Meanwhile, LCU-103 as a LMOF sensor exhibits several advantages such as high sensitivity, appropriate selectivity (for Fe 3+ in H 2 O), recycling stability, and fast response times in N, N…

A new metal–organic framework (MOF), [Zn 4 (μ 4 -O)(μ 6 -L) 2 (H 2 O) 2 ] n · n DMF (ZSTU-10), was assembled from zinc(II) nitrate and N, N ′, N ″-bis(4-carboxylate)trimesicamide linkers and fully characterized. Its crystal structure discloses an intricate two-fold 3D+3D interpenetrated MOF driven by the [Zn 4 (μ 4 -O)]-based tetragonal secondary building units and the C3-symmetric tris-amide-tricarboxylate linkers (μ 6 -L 3– ). Topological analysis of ZSTU-10 reveals two interpenetrated 3,6-connected nets with an rtl (rutile) topology. Z -Scan analysis at 532 nm was conducted to study a nonlinear optical (NLO) behavior of ZSTU-10. The nonlinear responses of ZSTU-10 were explored under various laser intensities, revealing notable third-order NLO properties in the visible region. A large two-photon absorption at lower incident intensities highlights the fact that ZSTU-10 can be applied in optical limiting devices as well as optical modulators. Moreover, a nonlinear refractive index ( n 2 ) is indicative of a self-defocusing behavior. This work thus expands a family of novel MOF…

Carbon dioxide (CO 2 ) fixation to generate chemicals and fuels is of high current importance, especially toward finding mild and efficient strategies for catalytic CO 2 transformation to value added products. Herein, we report a novel Lewis acid–base bifunctional amine-functionalized dysprosium(III) metal–organic framework [Dy 3 (data) 3 ·2DMF]·DMF (2,5-data: 2,5-diamino-terephthalate), NH 2 -TMU-73. This compound was fully characterized and its crystal structure reveals a 3D metal–organic framework (MOF) with micropores and free NH 2 groups capable of promoting the chemical fixation of CO 2 to cyclic carbonates. NH 2 -TMU-73 is built from the Dy(III) centers and data 2– blocks, which are arranged into an intricate underlying net with a rare type of xah topology. After activation, NH 2 -TMU-73 and its terephthalate-based analogue (TMU-73) were applied for CO 2 -to-epoxide coupling reactions to produce cyclic carbonates. Important features of this catalytic process concern high efficiency and activity in the absence of cocatalyst, use of solvent-free medium, atmospheric CO 2…

Electrolysis of seawater can not only desalinate seawater but also produce high-purity hydrogen. Nevertheless, the presence of chloride ions in seawater will cause electrode corrosion and also undergo a chlorine oxidation reaction (ClOR) that competes with the oxygen evolution reaction (OER). Therefore, highly efficient and long-term stable electrocatalysts are needed in this field. In this work, an advanced bifunctional electrocatalyst based on NiFe layered double hydroxide (LDH)/FeOOH heterostructure nanosheets (NiFe LDH/FeOOH) was synthesized on nickel–iron foam (INF) via a simple electrodeposition method. The NiFe LDH/FeOOH electrode demonstrates excellent electrocatalytic activity and stability, which results from the strong interaction between FeOOH and NiFe LDH. Furthermore, ex situ X-ray photoelectron spectroscopy (XPS) and in situ Raman spectroscopy revealed the catalytic process and also demonstrated that the NiFe LDH/FeOOH heterostructure could facilitate the formation of active NiOOH species in the reaction. The obtained NiFe LDH/FeOOH catalyst displays low…

Controlling the growth of metal–organic frameworks (MOFs) at the micro-/nanoscopic scale will result in new physical properties and novel functions into the materials without changing the chemical identities and the characteristic features of the MOFs themselves. Herein, we report a facile approach to synthesize a series of MOFs [Co-MOF, Co x Ni y -MOFs ( x and y represent the molar ratio of Co 2+ and Ni 2+ and x / y = 1:1, 1:5, 1:10, 1:15, and 1:20), and Ni-MOF] with a one-dimensional micro-/nanoscaled rod-like architecture. From Co-MOF to Co x Ni y -MOFs to Ni-MOF, the diameters of the rods turn to be spindly with the increase of Ni 2+ content which will facilitate the supercapacitor performances. Interestingly, Co 1 Ni 20 -MOF exhibits a highest specific capacity of 597 F g –1 at 0.5 A g –1 and excellent cycle performance (retained 93.59% after 4000 cycles) among these MOF materials owing to its micro-/nanorod structure with a smaller diameter and the synergy effect between the optimum molar ratio of Co 2+ and Ni 2+ .

Production of hydrogen by water electrolysis is an environment-friendly method and comparatively greener than other methods of hydrogen production such as stream reforming carbon, hydrolysis of metal hydride, etc. However, sluggish kinetics of the individual half-cell reactions hinders the large-scale production of hydrogen. To minimize this disadvantage, finding an appropriate, competent, and low-cost catalyst has attracted attention worldwide. Layer double hydroxide (LDH)-based materials are promising candidates for oxygen evolution reaction (OER) but not fruitful and their hydrogen evolution reaction (HER) activity is very poor, due to the lack of ionic conductivity. The inclusion of chalcogenide and generation of inherent oxygen vacancies in the lattice of LDH lead to improvement of both OER and HER activities. The presence of rich oxygen vacancies was confirmed using both the Tauc plot (1.11 eV, vacancy induction) and the photoluminescence study (peak at 426 nm, photoregeneration of oxygen). In this work, we have developed vacancy-enriched, selenized CoFe-LDH by the consequent…

Supramolecular coordination complexes with solid-state stimuli-responsive characteristics are highly desirable but are rarely reported. Herein, we describe two coordination-driven self-assembled monoanthracene or dianthracene-based hexagonal metallacycles by subtle structure modification. Notably, the dianthracene-containing hexagon 1 exhibits tricolor mechanochromic and vapochromic characteristics, while the monoanthracene-containing hexagon 4 does not show obvious changes toward mechanical force. Further studies have indicated that changes in hexagon 1, especially the ulterior anthracene of hexagon 1 in the molecular stacking through intermolecular interactions toward external stimuli, are responsible for the above behavioral differences. Furthermore, the present work also demonstrates a novel light-harvesting strategy for achieving high-contrast mechanochromic fluorescence involving solid-state energy transfer from hexagon 1 to an organic carbazole derivant 6 without mechanofluorochromism or tetraphenylethylene derivant 7 exhibiting inconspicuous mechanofluorochromism.

The development of porphyrin-based metal–organic frameworks (MOFs) has attracted significant interest in the scientific community in recent years because of their versatile applications particularly in optical and electronic fields. In this study, a highly selective and sensitive fluorescent turn-on sensor using a porphyrinic MOF, Tb–TCPP, is presented, which displays a 10-fold fluorescence enhancement in the presence of Al 3+, Cr 3+, and Fe 3+ ions. The detection limit is in the nM region. For the Al 3+ ion, it could be visually detected at concentrations as low as 5 mM within 15 min. Tb–TCPP could also be used as an indicator for acidic or alkaline solutions at pH values of >9 and <3. The studies on the detection mechanism illustrate that cation exchange proceed between Tb–TCPP and these M 3+ ions, and consequently, energy transfer from TCPP to Tb 3+ is suppressed and π*−π energy transfer of the porphyrin ligand is significantly enhanced.

It is of great importance to rationally design and develop earth-abundant nanocatalysts for high-efficiency water electrolysis. Herein, NiFe layered double hydroxide was in situ grown hydrothermally on a 3D graphite felt (NiFe LDH/GF) as a high-efficiency catalyst in facilitating the oxygen evolution reaction (OER). In 1.0 M KOH, NiFe LDH/GF requires a low overpotential of 214 mV to deliver a geometric current density of 50 mA cm –2 (η 50 mA cm –2 = 214 mV), surpassing that NiFe LDH supported on a 2D graphite paper (NiFe LDH/GP; η 50 mA cm –2 = 301 mV). More importantly, NiFe LDH/GF shows good durability at 50 mA cm –2 within 50 h of OER catalysis testing and delivers a faradaic efficiency of nearly 100% in the electrocatalysis of OER.

Fluoroquinolone antibiotic (FQ) residues, such as ciprofloxacin (CIP) and ofloxacin (OFLX), have aroused public concerns owing to their serious impact in environmental water or food fields which influence human health. A facile and high-performance sensory method for detecting FQs is highly desirable for practical requirements. Herein, we have presented a luminescent Eu-MOF with unique 2D (4-c) {4 4 .6 2 }-connected topology, which holds the outstanding fluorescent property and excellent chemical stability in aqueous solution for 15 days. Thus, Eu-MOF can be considered as a highly sensitive chemo-sensor for sensing CIP and OFLX with different fluorescent color conversion (red changes to green for OFLX and to blue for CIP) and a low detection limit of 0.693 and 0.802 ppb, respectively. Furthermore, the mechanism of sensing CIP and OFLX was exposed to the photoinduced electron transfer (PET) and dynamic quenching process, as evaluated by DFT calculations and fluorescence lifetime decay measurements. Our work first reports a simple and efficient strategy for recognizing CIP and OFLX…

Developing high-performance and cost-efficient catalysts toward oxygen evolution reaction (OER) is an important but daunting task due to the sluggish kinetics hindered by the four-electron transfer process. Herein, an advanced class of ultralow Ru-doped NiCo-MOF hollow porous nanospheres (denoted as Ru@NiCo-MOF HPNs) has been reported in this work. Benefiting from the high porosity and large surface area of the metal–organic frameworks (MOFs) and optimized electronic properties by Ru doping, the as-prepared Ru@NiCo-MOF HPNs exhibit superior performance for water oxidation with the overpotential of only 284 mV to reach a current density of 10 mA·cm –2 in alkaline electrolyte, as well as a small Tafel slope of 78.8 mV·dec –1, outperforming the NiCo-MOF HPNs (358 mV) and commercial RuO 2 catalyst (326 mV). The incorporation of Ru in NiCo-MOF HPNs enables a stable OER activity for at least 39 h. Moreover, we have probed the interaction between the content of Ru and OER performance, impressively, Ru@NiCo-MOF HPNs with 13.5 atom % Ru doping (denoted as Ru@NiCo-MOF-4) exhibited the highest…

A half-conjugate polydentate Salamo–Salen hybrid ligand, H 5 L, containing two unique N 2 O 2 pockets was first designed so that these metal ions in the complexes appear in different coordination modes. Two heterohexanuclear 3d–s double-helical cluster complexes, [Zn 4 Ca 2 L 2 (μ 1 -OAc) 2 (EtOH) 2 ]·2EtOH ( 1; EtOH = ethanol) and [Zn 4 Sr 2 L 2 (μ 2 -OAc) 2 (MeOH) 2 ]·2CH 2 Cl 2 ( 2; MeOH = methanol), are reported that are formed through the reaction of H 5 L with zinc(II) and calcium(II) acetate or strontium(II) acetate, respectively. IR spectral analysis of the two complexes showed the existence of monodentate- and bidentate-coordinated acetate ions. The fluorescence properties of the ligand and its two heterohexanuclear complexes were explored in MeOH and water solutions, separately. In addition, theoretical calculations (density functional theory, interaction region indicator, and bond order) were performed to further understand the formation of a single-molecular double helix and the electron distribution characteristics of the two complexes.

Metal–organic frameworks (MOFs) offer many opportunities for applications across biology and medicine. Their wide range of chemical composition makes toxicologically acceptable formulation possible, and their high level of functionality enables possible applications as delivery systems for therapeutics agents. Surface modifications have been used in drug delivery systems to minimize their interaction with the bulk, improving their specificity as targeted carriers. Herein, we discuss a strategy to achieve a tumor-targeting drug-loaded MOF using “click” chemistry to anchor functional folic acid (FA) molecules on the surface of N 3 -bio-MOF-100. Using curcumin (CCM) as an anticancer drug, we observed drug loading encapsulation efficiencies (DLEs) of 24.02 and 25.64% after soaking N 3 -bio-MOF-100 in CCM solutions for 1 day and 3 days, respectively. The success of postsynthetic modification of FA was confirmed by 1 H NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and liquid chromatography–mass spectrometry (LC-MS). The stimuli-responsive drug release studies…

The elaborately designed π-electron-rich fluorescent ligand 1,4-bis(1-carboxymethylene-4-imidazolyl)benzene (H 2 L), possessing bifunctional groups including the carboxylate groups (building units) and 4-imidazoyl groups (N-donor potential active sites) has been employed to construct fluorescent coordination polymers. A luminescent sensor, namely [Cd(L)(phen) 2 ]·5H 2 O ( 1 ), was obtained, which has a one-dimensional structure. The fluorescent material shows a blue emission maximum at 457 nm with a luminescence lifetime of 488 ns and a quantum yield (QY) of 4.56%. Significantly, 1 serves as a promising multiresponsive luminescent sensor to detect trace nitroaromatic compounds (NACs) with the limits of detection (LOD) of 7.21 × 10 –8, 1.85 × 10 –5, and 1.15 × 10 –5 mol/L for 2-nitrophenol (2-NP), 3-nitrophenol (3-NP), and 4-nitrophenol (4-NP), respectively. Furthermore, CP 1 exhibits fluorescent turn-off and turn-on sensing behavior for Fe 3+ and Al 3+ metal ions with trace amounts of 1.05 × 10 –7 and 1.13 × 10 –7 mol/L, respectively. Experimental methods and theoretical…

Coordination numbers and geometries form a theoretical framework for understanding and predicting materials properties. Algorithms to determine coordination numbers automatically are increasingly used for machine learning (ML) and automatic structural analysis. In this work, we introduce MaterialsCoord, a benchmark suite containing 56 experimentally derived crystal structures (spanning elements, binaries, and ternary compounds) and their corresponding coordination environments as described in the research literature. We also describe CrystalNN, a novel algorithm for determining near neighbors. We compare CrystalNN against seven existing near-neighbor algorithms on the MaterialsCoord benchmark, finding CrystalNN to perform similarly to several well-established algorithms. For each algorithm, we also assess computational demand and sensitivity toward small perturbations that mimic thermal motion. Finally, we investigate the similarity between bonding algorithms when applied to the Materials Project database. We expect that this work will aid the development of coordination prediction…

A series of 2D/2D exfoliated boron nitride/exfoliated g-C 3 N 4 nanocomposites denoted as e-BN/e-CN have been successfully prepared using a simple in situ technique. The successful deposition of e-BN on e-CN was confirmed from high-resolution transmission electron microscopy analysis. According to electrochemical measurements, 1.5 wt % e-BN/e-CN nanocomposites showed 1.5 times more photocurrent than e-CN, which indicates the successful formation of an e-BN/e-CN heterostructure. The photocatalytic activities of the e-CN and e-BN/e-CN composites were investigated through photocatalytic tetracycline hydrochloride (TCH) degradation and H 2 evolution under visible light illumination. The 1.5 wt % e-BN/e-CN composite demonstrated the highest photocatalytic activities, which are about 21 and 1.5 fold greater than e-CN towards H 2 generation with an apparent conversion efficiency of 2.34% and TCH degradation, respectively. The improved photocatalytic activities of e-BN/e-CN photocatalysts were ascribed to the augmented light-harvesting ability and enhanced separation efficiency of charge…

Defect influences on the photoactivity of ZnO nanoparticles prepared by a powdered coconut water (ACP) assisted synthesis have been studied. The crystalline phase and morphology of ZnO nanoparticles were effectively controlled by adjusting the calcination temperature (400–700 °C). An induced transition of hybrid Zn 5 (CO 3 ) 2 (OH) 6 /ZnO nanoparticles to single-phase ZnO nanoparticles was obtained at 480 °C. The morphological analysis revealed a formation of ZnO nanoparticles with semispherical (∼6.5 nm)- and rod-like (∼96 nm) shapes when the calcination temperatures were 400 and 700 °C, respectively. Photoluminescence characterizations revealed several defects types in the samples with V Zn and V O + being in the self-assembly of semispherical- and rod-like ZnO nanoparticles. The photocatalytic activity of the ZnO nanoparticles was examined by assessing the degradation of methylene blue in an aqueous solution under low-intensity visible-light irradiation (∼3 W m –2 ). The results point toward the self-assembly of semispherical- and rod-like ZnO nanoparticles that had significantly…

An efficient and heterogeneous novel magnetic silica-coated picolylaminecopper complex [Fe 3 O 4 @SiO 2 @GP/Picolylamine-Cu(II)] was synthesized, characterized, and employed as a magnetically recoverable nanocatalyst in Biginelli condensation for the preparation of biologically active 3,4-dihydropyrimidinones. Fe 3 O 4 @SiO 2 @GP/Picolylamine-Cu(II) was synthesized easily using chemical attachment of the picolylaminecompound on Fe 3 O 4 @SiO 2 @GP, followed by treatment with copper salt in ethanol under reflux conditions. Fe 3 O 4 @SiO 2 @GP/Picolylamine-Cu(II) was affirmed by various analyses such as Fourier transform infrared, thermogravimetric analysis, X-ray diffraction, vibrating-sample magnetometry, field-emission scanning electron microscopy, transmission electron microscopy, DLS, inductively coupled plasma, energy-dispersive X-ray spectrometry, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller. The resulting catalyst system was successfully used in the Biginelli reaction through a variety of compounds such as aromatic aldehyde, urea, and ethyl acetoacetate under…

Here, two novel 3D Cd(II)-MOFs, [Cd 3 · L ·( BTB ) 2 ·2DMF] and [(Cd 3 O 2 )· L · BTC ] (denoted as CUST-532 and CUST-533, L = 9,10-bis( N -benzimidazolyl)-anthracene, BTB = 1,3,5-tris(4-carboxyphenyl) benzene, BTC = 1,3,5-benzenetricarboxylic acid, CUST = Changchun University of Science and Technology), were synthesized by solvothermal conditions. Both CUST-532 and CUST-533 are 3D (3,8)-c topological nets with the same point symbol of {4 3 } 2 {4 6 ·6 18 ·8 4 }. PXRD and TGA analyses prove that CUST-532 and CUST-533 have good structural stability and thermal stability. On the basis of the high fluorescence characteristics, the results of fluorescence sensing experiments show that CUST-532 and CUST-533 can be used as multifunctional chemical sensors to achieve rapid fluorescence quenching response to antibiotic residues, Fe 3+ and Cr 2 O 7 2– ions at a much lower concentration. Furthermore, the possible mechanisms of fluorescence quenching in the sensing process were systematically studied by PXRD, UV–vis, fluorescence decay lifetime, and density functional theory.

Metal–organic frameworks (MOFs) and MOF-based composites as luminescent sensors with excellent economic practicability and handy operability have attracted much attention. Herein, we designed and fabricated a porous Zn-based MOF, [Zn(OBA) 2 (L 1 )·2DMA] n [ 1; H 2 OBA = 4,4′-oxybis(benzoic acid), L 1 = 2,4,6-tris(4-pyridyl)pyridine, and DMA = N, N -dimethylacetamide], with mixed nodes under solvothermal conditions, and the pore size of 5.9 Å was calculated from N 2 adsorption isotherms by using a density functional theory model. The as-synthesized compound 1 is stable in different boiling organic solvents and water solutions with a wide pH range of 2–12 and exhibits intense luminescence emission at 360 nm under excitation of 290 nm. Significantly, compound 1 shows high selective detection of Fe 3+, CrO 4 2–, and Cr 2 O 7 2– in aqueous solution even under the interference of other ions. Compound 1 can quickly sense these ions in a short time and has a striking sensitivity toward Fe 3+ with an ultralow limit of detection (LOD) of 1.06 μM. The relatively low LODs for CrO 4 2– and Cr 2…

In this work, a metal–organic framework (MOF) material of NH 2 -MIL88B was hybridized with TpPa-1-COF through covalent bonding, and the hybrid was subsequently employed for the degradation of Rhodamine B (RhB) and tetracycline (TC) by simulated sunlight-induced Fenton-like exciting H 2 O 2 . The obtained results show that its photocatalytic activity is much better than those of its parent MOF and covalent organic framework (COF). Moreover, it is much higher than that of bare photocatalysis without Fenton-like excitation of H 2 O 2 . The high degradation efficiency is ascribed to two factors. One is the formation of hybrid, which promotes charge separation and light absorbance. Another is the Fenton-like excitation of H 2 O 2, which produces more hydroxyl radicals ( • OH). This report presents a facile approach to greatly improve the photocatalytic property of MOF materials by the formation of hybrid with COFs and Fenton-like excitation of H 2 O 2 .

To resolve the fleeting structures of lanthanide Ln 3+ aqua ions in solution, we (i) performed the first ab initio molecular dynamics (AIMD) simulations of the entire series of Ln 3+ aqua ions in explicit water solvent using pseudopotentials and basis sets recently optimized for lanthanides and (ii) measured the symmetry of the hydrating waters about Ln 3+ ions (Nd 3+, Dy 3+, Er 3+, Lu 3+ ) for the first time with extended X-ray absorption fine structure (EXAFS). EXAFS spectra were measured experimentally and generated from AIMD trajectories to directly compare simulation, which concurrently considers the electronic structure and the atomic dynamics in solution, with experiment. We performed a comprehensive evaluation of EXAFS multiple-scattering analysis (up to 6.5 Å) to measure Ln–O distances and angular correlations (i.e., symmetry) and elucidate the molecular geometry of the first hydration shell. This evaluation, in combination with symmetry-dependent L 3 - and L 1 -edge spectral analysis, shows that the AIMD simulations remarkably reproduces the experimental EXAFS data. The…

The design and development of self-calibrating ratiometric luminescent sensors for the fast, accurate, and sensitive discrimination and determination of pollutants in wastewater is highly desirable for public and environmental health. Herein, a 3D porous Tb(III)-based metal–organic framework (MOF), {[Tb(HL)(H 2 O) 2 ]· x (solv)} n ( 1 ), was facilely synthesized using a urea-functionalized tetracarboxylate ligand, 5,5′-(((1,4-phenylenebis(azanediyl))bis(carbonyl))bis(azanediyl))diisophthalic acid (H 4 L). The activated framework showed a good water stability in both aqueous solutions at a wide pH range of 2–14 and simulated antibiotic wastewaters. Interestingly, this Tb-MOF exhibited dual luminescence owing to the partial energy transfer from the antenna H 4 L to Tb 3+ . More importantly, activated 1 ( 1a ) that was dispersed in water showed a fast, accurate, and highly sensitive discrimination ability toward antibiotics with a good recyclability, discriminating three different classes of antibiotics from each other via the quenching or enhancement of the luminescence and tuning the…

Developing highly efficient non-precious electrocatalytic materials for H 2 production in an alkaline medium is attractive on the front of green energy production. Herein, we successfully designed an electrocatalyst with superb hydrophilicity, high conductivity, and a kinetically beneficial structure using Ni 2 P/MXene over a 3D Ni foam (NF) for the alkaline hydrogen evolution reaction (HER) based on the laboratory and computational research works. The designed self-supported and highly effective electrocatalyst achieves a huge boost in the HER activity compared with that of pristine Ni 2 P nanosheets owing to the distinctive structure and synergy of coupling Ti 3 C 2 T x and Ni 2 P. More specifically, Ni 2 P/Ti 3 C 2 T x /NF produces an electric current density of 10 mA·cm –2 under a low overpotential (135 mV) and shows excellent durability under alkaline (1 M KOH) conditions, and the observed performance degradation is negligible. The outstanding HER activity makes the synthetic strategy of Ni 2 P/Ti 3 C 2 T x /NF a potential approach to be extended to other transition-metal-based…

The development of lead-free ceramics with appropriate energy storage properties is essential for the successful practical application of advanced electronic devices. In this study, a site engineering strategy was proposed to concurrently decrease grain size, increase the band-gap, and enhance the relaxor nature in Ta-doped tungsten bronze ceramics (Sr 2 NaNb 5– x Ta x O 15 ) for the improvement of the dielectric breakdown strength and the polarization difference. As a result, the ceramic with x = 1.5, that is, Sr 2 NaNb 3.5 Ta 1.5 O 15, exhibited superior energy density (∼3.99 J/cm 3 ) and outstanding energy efficiency (∼91.7%) (@380 kV/cm) as well as good thermal stability and remarkable fatigue endurance. In addition, the ceramic demonstrated an ultrashort discharge time (τ 0.9 < 57 ns), a high discharge current density (925.8 A/cm 2 ) along with a high power density (78.7 MW/cm 3 ). The energy storage properties in combination with good stability achieved in this work indicate the powerful potential of Sr 2 NaNb 5– x Ta x O 15 tungsten bronze ceramics for high-performance…

Metal–organic frameworks (MOFs) are important photocatalytic materials for H 2 production. To clarify the structure–function relationship and improve the photocatalytic activity, herein we explored a series of porphyrin-based zirconium MOFs (PCN-H 2 /Pt x: y, where x: y = 4:1, 3:2, 2:3, and 0:1) containing different ratios of H 2 TCPP and Pt II TCPP [TCPP = tetrakis(4-carboxyphenyl)porphyrinate] as isostructural ligands and Zr 6 clusters as nodes. Under visible-light irradiation, PCN-H 2 /Pt 0:1 shows the highest average H 2 evolution reaction rate (351.08 μmol h –1 g –1 ), which decreases along with lowering of the ratio of Pt II TCPP in the PCN-H 2 /Pt x: y series. The differences in photocatalytic activity are attributed to more uniformly dispersed Pt 2+ ions in PCN-H 2 /Pt 0:1, which promotes charge transfer from porphyrins (photosensitizers) to Pt II ions (catalytic centers), leading to efficient charge separation in the MOF materials. The bifunctional MOFs with photosensitizers and catalytic centers provide new insight for the design and application of porphyrin-based…

We report the construction of a porphyrin and imidazolium-ionic liquid (IL)-decorated and quinoline-linked covalent organic framework (COF, abbreviated as COF-P1-1 ) via a three-component one-pot Povarov reaction. After post-synthetic metallization of COF-P1-1 with Co(II) ions, the metallized COF-PI-2 is generated. COF-PI-2 is chemically stable and displays highly selective CO 2 adsorption and good visible-light-induced photothermal conversion ability (Δ T = 26 °C). Furthermore, the coexistence of Co(II)–porphyrin and imidazolium-IL within COF-PI-2 has guaranteed its highly efficient activity for CO 2 cycloaddition. Of note, the needed thermal energy for the reactions is derived from the photothermal conversion of the Co(II)–porphyrin COF upon visible-light irradiation. More importantly, the CO 2 cycloaddition herein is a “window ledge” reaction, and it can proceed smoothly upon natural sunlight irradiation. In addition, a scaled-up CO 2 cycloaddition can be readily achieved using a COF-PI-2@chitosan aerogel -based fixed-bed model reactor. Our research provides a new avenue for…

Low-dimensional hybrid organic–inorganic metal halides have received increased attention because of their outstanding optical and electronic properties. However, the most studied hybrid compounds contain lead and have long-term stability issues, which must be addressed for their use in practical applications. Here, we report a new zero-dimensional hybrid organic–inorganic halide, RInBr 4, featuring photoemissive trimethyl(4-stilbenyl)methylammonium (R + ) cations and nonemissive InBr 4 – tetrahedral anions. The crystal structure of RInBr 4 is composed of alternating layers of inorganic anions and organic cations along the crystallographic a axis. The resultant hybrid demonstrates bright-blue emission with Commission Internationale de l’Eclairage color coordinates of (0.19, 0.20) and a high photoluminescence quantum yield (PLQY) of 16.36% at room temperature, a 2-fold increase compared to the PLQY of 8.15% measured for the precursor organic salt RBr. On the basis of our optical spectroscopy and computational work, the organic component is responsible for the observed blue emission of…

The relationship between the aggregation states of pyrene-based linkers and the photoluminescence/photoelectric performance was well studied by the formation of an anionic metal–organic framework, [BMI] 2 [Mg 3 (TBAPy) 2 (H 2 O) 4 ]·2dioxane, which shows highly enhanced light-harvesting and photoelectric conversion efficiency by the encapsulation of D−π–A cation dyes.

Mechanoluminescent materials have shown great application potential in the fields of stress detection, anti-counterfeiting, and optical storage; however, its development is hindered by the unclear mechanism. Different from the mainstream exploration of new mechanoluminescent materials in non-centrosymmetric structures, a centrosymmetric mechanoluminescent material Li 2 ZnGeO 4:Mn 2+ is synthesized by a standard high-temperature solid-state reaction in an ambient atmosphere. Combined with the Rietveld refinement, photoluminescence, electron spin resonance, and X-ray photoelectron spectroscopy, it is proved that the increase in oxygen vacancies is accompanied by the self-reduction process from Mn 4+ to Mn 2+, and the mechanism of mechanoluminescence is clarified through the afterglow and thermoluminescence spectra. The carriers trapped by the shallow traps participate in the mechanoluminescence process through the tunneling effect, while the carriers trapped by the deep traps take part in the mechanoluminescence process via conduction band or tunneling. A signature anti-counterfeiting…

Electrochemical water splitting is regarded as the most potential sustainable hydrogen production technology. However, the slow reaction kinetics and high overpotential of this process will result in low energy conversion efficiency. Therefore, it is of great practical value to research low-cost, efficient, and stable transition-metal-based bifunctional electrocatalysts. Herein, Fe–Co Prussian blue analogue (PBA) was coated with Ni–Co PBA to prepare the trimetallic PBA precursor, and the trimetallic phosphate (Fe–Co–Ni–P-1) has been prepared via the low-temperature phosphating process. The effects of metal ratios, the amount of sodium hypophosphite, and phosphating temperature on the catalytic performances were studied. When Fe–Co–Ni–P-1 was used as an electrocatalyst, the overpotential of oxygen evolution reaction and hydrogen evolution reaction was 247 and 215 mV, respectively, at a current density of 10 mA cm –2 . At the same time, Fe–Co–Ni–P-1 showed faster kinetics and better long-term stability in the catalytic process. The catalytic performances of unary metal, binary metal,…

-chelating salphen-like metallic core as a promising scaffold to be explored in the design of future tailor-made Cu(II) cytotoxic compounds.

A tetraimidazole-decorating tetraphenylpyrazine has been designed and utilized for the fabrication of a novel metal–organic framework (MOF), denoted as {Mn(Tipp)(A) 2 } n ·2H 2 O (TippMn, where Tipp = 2,3,5,6-tetrakis[4-[(1 H -imidazol-1-yl)methyl]phenyl]pyrazine and A = deprotonation of 1,4-naphthalenedicarboxylic acid), through hydrothermal synthesis. Structural analysis reveals that TippMn possesses a 2-fold-interpenetrated 4,8-connected three-dimensional (3D) network with an unprecedented {4 16 ·6 12 }{4 4 ·6 2 } topology. Fluorescent spectral investigations indicate that TippMn shows discriminative fluorescence when treated by Cr 3+ and Cu 2+, giving an INHIBIT logical gate performance. Meanwhile, TippMn can be further used as a sensor for MnO 4 – and 2,4,6-trinitrophenol (TNP) by fluorescence quenching. Notably, the sensing processes toward Cu 2+, Cr 3+, MnO 4 –, and TNP are labeled with high selectivity and sensitivity, quick response, and good recyclability. It is anticipated that this MOF-based versatile sensor could shed light on the exploration of MOFs for fluorescent…

The explorations of earth-abundant, noble metal-free, highly efficient electrocatalysts for water-splitting reactions have been considered as highly significant for imperishable energy production. Though the metal organic framework (MOF)-based materials are highly promising candidates in the area of material chemistry, the combined properties associated with MOFs and the one-dimensional (1D) fibrous matrix, which can lead to better electrocatalytic performance, have been less explored. Herein, we ascertain a fabrication method for ZIF-67 (zeolite imidazolate framework) nanofibers (NFs), Fe-ZIF NFs, and Fe-ZIF-67 NFs via the wet chemical combined electrospinning (ES) approach. The as-synthesized catalysts were utilized for the electrochemical reaction, which showed a high efficiency toward the oxygen evolution reaction (OER). Compared to other catalysts, the Fe-ZIF-67 NF catalyst showed a very less overpotential of 278 mV at a fixed current density of 10 mA cm –2 . The obtained Tafel slope and R ct values are 77 mV dec –1 and 1.2 Ω, respectively. The post-X-ray photoelectron…

The increasing demand for energy storage materials has gained considerable attention of scientific community toward the development of hydrogen storage materials. Hydrogen has become more important, as it not only works efficiently in different processes but is also used as an alternative energy resource whenever it is combined with a cell technology like fuel cell. Herein, efforts are being made to develop efficient hydrogen storage materials based on alkaline earth metal (beryllium, magnesium, and calcium)-encapsulated B 12 N 12 nanocages. Quantum chemical calculations were performed using density functional theory (DFT) and time-dependent DFT at B3LYP/6-31G(d,p) and CAM-B3LYP/6-311+G(d,p) levels of theory for all the studied systems. The adsorption energies of Be-B 12 N 12, Mg-B 12 N 12, and Ca-B 12 N 12 systems suggested that Mg and Ca are not fitted accurately in the cavity of nanocages because of their large size. However, H 2 adsorbed efficiently on the metal-encapsulated systems with high adsorption energy values. Furthermore, dipole moment and Q NBO (Charges-Natural Bond…

The linkage of molecular components into functional heterogeneous framework materials has revolutionized modern materials chemistry. Here, we use this principle to design polyoxometalate-based frameworks as high affinity adsorbents for drugs of abuse, leading to their application in solid-phase extraction analysis. The frameworks are assembled by the reaction of a Keggin-type polyanion, [SiW 12 O 40 ] 4–, with lanthanoids Dy(III), La(III), Nd(III), and Sm(III) and the multidentate linking ligand 1,10-phenanthroline-2,9-dicarboxylic acid (H 2 PDA). Their reaction leads to the formation of crystalline 1D coordination polymers. Because of the charge mismatch between the lanthanoids (+3) and the dodecasilicotungstate (−4), we observe incorporation of the PDA 2– ligands into crystalline materials, leading to four polyoxometalate-based frameworks where Keggin-type heteropolyanions are linked by cationic {Ln n (PDA) n } groups (Ln = Dy ( 1 ), La ( 2 ), Nd ( 3 ), and Sm ( 4 )). Structural analysis of the polyoxometalate-based frameworks suggested that they might be suitable for surface…

Corresponding to the absorption curve of plant photosensitive pigment Pfr, near-infrared light has a broad application prospect in plant lighting. In order to explore this plant growth lamp, the novel near-infrared emitting phosphor LaMg 0.5 Sn 0.5 O 3:Cr 3+ was synthesized, which can be efficiently excited by 467 nm blue light. There are two luminescence centers, which were proven by testing the low-temperature spectrum, the excitation spectrum at different wavelengths, and the lifetime decay curve, and the two cell sequence substitution processes were obtained by Rietveld refinements of XRD. By introducing Ge 4+, its luminescence intensity has been increased 1.6 times and the intensity at 150 °C remains at almost 80% that at room temperature. Finally, two different kinds of illumination experiments for plant growth were carried out, and the feasibility of the LaMg 0.5 (SnGe) 0.5 O 3:Cr 3+ phosphor for plant growth was confirmed.

Cadmium-free quantum dots (QDs) consisting of silver–indium–gallium–sulfide (AIGS) quaternary semiconductors were successfully synthesized using a metal–dithiocarbamate complex with sufficiently high reactivity to produce metal sulfides. The introduction of a gallium diethyldithiocarbamate precursor decreased the reaction temperature to produce active intermediates, which were subsequently converted into AIGS QDs at 150 °C with silver and indium acetates. Because of the low reaction temperature, AIGS QDs with a tetragonal crystal phase were produced selectively, which favorably generated band-edge emission whose full width at half-maximum is smaller than 40 nm after they were coated with gallium sulfide (GaS y ) shells. The compositional indium/gallium ratio was varied by changing the mixing ratio of the precursors used for the synthesis of the AIGS core, and the band-edge photoluminescence (PL) generated from the AIGS/GaS y core/shell QDs was blue-shifted with an increase in the gallium content in the core. Consequently, a pure green emission centered at 518 nm was obtained with a…

Altering the morphology of electrochemically active nanostructured materials could fundamentally influence their subsequent catalytic as well as oxygen evolution reaction (OER) performance. Enhanced OER activity for mixed-metal spinel-type sulfide (CuCo 2 S 4 ) nanorods is generally done by blending the material that has high conductive supports together with those having a high surface volume ratio, for example, graphitic carbon nitrides (g-C 3 N 4 ). Here, we report a noble-metal-free CuCo 2 S 4 nanorod-based electrocatalyst appropriate for basic OER and neutral media, through a simple one-step thermal decomposition approach from its molecular precursors pyrrolidine dithiocarbamate-copper(II), Cu[PDTC] 2, and pyrrolidine dithiocarbamate-cobalt(II), Co[PDTC] 2 complexes. Transmission electron microscopy (TEM) images as well as X-ray diffraction (XRD) patterns suggest that as-synthesized CuCo 2 S 4 nanorods are highly crystalline in nature and are connected on the g-C 3 N 4 support. Attenuated total reflectance–Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy…

Abnormal bilirubin (BR) level is a sign of several fatal diseases, so it is of great significance and challenge to develop a facile and effective family routine strategy for BR sensing. Herein, novel water-stable Tb 3+ @MOF-808 has been synthesized using a coordinated postsynthetic modification strategy and designed as a convenient and efficient fluorescence probe. The fabricated fluorescent probe exhibits a remarkable fluorescence quenching effect with the successive addition of BR, which displays fascinating features, such as fast response time, high sensitivity, and excellent selectivity. The quenching mechanism between the fluorescent probe and BR was also illustrated in detail. Importantly, the devised fluorescent probe successfully achieved the determination of BR in serum and urine, which has also been successfully used in the design of portable BR test paper. The developed monitoring platform for BR levels in vivo provides promising application potential for the prevention and early diagnosis of fatal diseases. Additionally, a molecular logic gate device that performs…

Low-dimensional organic–inorganic metal halides have recently emerged as a class of promising luminescent materials. However, the intrinsic toxicity of lead would strongly hamper future application. Herein, we synthesized a new type of lead-free zero-dimensional (0D) antimony-based organic–inorganic metal halide single crystals, (PPZ) 2 SbCl 7 ·5H 2 O (PPZ = 1-phenylpiperazine), which features a broadband emission at 720 nm. Ultrafast transient absorption and temperature-dependent photoluminescence (PL) spectra are combined to investigate the PL mechanism, revealing that self-trapped exciton recombination was involved. Furthermore, it is interesting that (PPZ) 2 SbCl 7 ·5H 2 O material shows reversible PL emission transformation between red light (720 nm) and yellow light (590 nm) as water molecules are inserted or removed from the lattice. Such reversible emission transformation phenomenon renders the (PPZ) 2 SbCl 7 ·5H 2 O as a potential low-cost water sensing material.

The universal pollution of diverse water bodies and declined water quality represent very important environmental problems. The development of new and efficient photocatalytic water treatment systems based on the Z-scheme mechanisms can contribute to tackling such problems. This study reports the preparation, full characterization, and detailed sonophotocatalytic activity of a new series of hybrid NU@ZIS nanocomposites, which comprise a p–n heterojunction of 3D Zr(IV) metal–organic framework nanorods (NU-1000) and photoactive ZnIn 2 S 4 (ZIS) nanostars. Among the obtained materials with varying content of ZIS (5, 10, 20, and 30%) on the surface of NU-1000, the NU@ZIS20 nanocomposite revealed an ultrahigh catalytic performance and recyclability in a quick visible-light-induced degradation of the tetracycline antibiotic in water under sonophotocatalytic conditions. Moreover, increased activity of NU@ZIS20 can be ascribed to the formation of a p–n heterojunction between NU-1000 and ZIS, and a synergistic effect of these components, leading to a high level of radical production,…

In the field of agriculture fungicides are vital, providing the most important ecosystem service for food production. The widespread use of these chemicals can significantly lead to various ecotoxicological threats with adverse effects, such as environmental changes, microbial resistance, and phytotoxicity. Electrochemical sensors offer enormous potential for the identification and monitoring of hazardous substances in accordance with their constructive characteristics, namely, precision, accuracy, sensitivity, and selectivity, over traditional analytical techniques. Here, we thus report the synthesis of the lanthanum vanadate/hexagonal boron nitride (LaV/h-BN) composite for the electrochemical determination of carbendazim (CZ), which is a widely used fungicide for disease management with critical risks associated with its overexposure. The combination of LaV and h-BN accelerates the formation of active sites, facilitating faster charge transfer and higher electronic conductivity. The synergistic effects greatly improve the preference of the modified electrode with increased…

Owing to their characteristic structures, metal–organic frameworks (MOFs) are considered as the leading candidate for drug-delivery materials. However, controlling the synthesis of MOFs with uniform morphology and high drug-loading/release efficiencies is still challenging, which greatly limits their applications and promotion. Herein, a multifunctional MOF-based drug-delivery system (DDS) with a controlled pore size of 100–200 nm for both therapeutic and bioimaging purposes was successfully synthesized in one step. Fe-MOF-based microcapsules were synthesized through a competitive coordination method, which was profited from the intrinsic coordination characteristics of the Fe element and the host-guest supramolecular interactions between Fe 3+ and polyoxometalates anions. This as-synthesized macroporous DDS could greatly increase the drug-loading/release rate (77%; 83%) and serve as a magnetic resonance (MR) contrast agent. Because an Fe-containing macroporous DDS presents ultrahigh drug loading/release, the obtained 5-FU/Fe-MOF-based microcapsules displayed good biocompatibility,…

A rational design of a novel ternary-shelled nanotube is attractive in photocatalytic water splitting. Herein, ZnIn 2 S 4 nanosheets were in situ grown on the surface of MIL-88A-derived Ni–Fe layered double hydroxide (LDH) to fabricate ternary-shelled nanotubes (ZIS@Ni–Fe LDH) via a self-assembly strategy. Characterization indicates that the ZIS@Ni–Fe LDH heterostructure exhibits a high surface area and a well-defined ternary-shelled hollow structure. The optimal heterostructure presents a remarkably improved photocatalytic hydrogen production rate (2035.81 μmol g –1 h –1 ) compared with bare ZnIn 2 S 4 and MIL-88A-derived Ni–Fe LDH under visible light illumination. The effect of ZnIn 2 S 4 loading on the photocatalytic performance and stability of ZIS@Ni–Fe LDH is systematically studied. The ZIS@Ni–Fe LDH heterostructure can make better use of the inner space, provide abundant reactive sites, improve light harvesting, accelerate interfacial electron transfer, and further promote photocatalytic hydrogen evolution. Based on the electrocatalytic performance, the probable…

Two novel 3D fluorescent metal–organic frameworks (MOFs), [Cd(L)(bbibp)] n ( 1 ) and [Cd(L)(bbibp) 0.5 ] n ( 2 ), where H 2 L = 4,4′-(4,4′-bipyridine-2,6-diyl)dibenzoic acid and bbibp = 4,4′-bis(benzoimidaz-1-yl)biphenyl, were acquired through a conventional method and characterized via IR spectra, single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction (PXRD), scanning electron microscopy, N 2 adsorption–desorption isotherms, and X-ray photoelectron spectroscopy (XPS). The crystal framework of Cd-MOF 1 remained stable in the range of pH = 1.0–12.0. Interestingly, the emission peak of 1 showed a red shift and exhibited a fluorescence turn-on effect in an acidic environment. X-ray diffraction measurement revealed that the crystal structure of 1 remained unchanged after immersion in a pH = 1.0 solution. In addition, Cd-MOFs 1 and 2 displayed fluorescent quenching to l -glutamic acid with high sensitivity and selectivity. Meanwhile, 1 showed high selectivity in recognizing Fe 3+ under acidic conditions, which made 1 capable of…

Herein, we report a dia -type metal–organic hybrid network based on the [Ag 4 Br 6 ] clusters and hexamethylenetetramine molecules wherein both the inorganic nodes and organic linkers feature adamantane-like geometry with a T d symmetry. The silver bromine complex presents a dual emission and exhibits an interesting luminescent thermochromism behavior. Remarkably, white-light emission can be readily realized through variation of the temperature. In addition, the title compound is expected to be competent as a luminescent thermometer for temperature identification.

The functionalization of C-H bonds is one of the most challenging transformations in synthetic chemistry. In biology, these processes are well-known and are achieved with a variety of metalloenzymes, many of which contain a single metal center within their active sites. The most well studied are those with Fe centers, and the emerging experimental data show that high-valent iron oxido species are the intermediates responsible for cleaving the C-H bond. This Forum Article describes the state of this field with an emphasis on nonheme Fe enzymes and current experimental results that provide insights into the properties that make these species capable of C-H bond cleavage. These parameters are also briefly considered in regard to manganese oxido complexes and Cu-containing metalloenzymes. Synthetic iron oxido complexes are discussed to highlight their utility as spectroscopic and mechanistic probes and reagents for C-H bond functionalization. Avenues for future research are also examined.

Zero-dimensional (0D) metal halides with solid-state luminescence switching (SSLS) have attracted attention as sensors and luminescent anticounterfeiting. Herein, selective solvent molecule response and accordingly luminescence switching were discovered in 0D [EtPPh 3 ] 2 [SbCl 5 ] ( 1, EtPPh 3 = ethyltriphenylphosphonium). More than a dozen kinds of solvent molecules have been tested to find out the selection rule for molecule absorption in 1, which is demonstrated to be the size effect of guest molecules. Confirmed by crystal structural analysis, only the solvents with molecular volume less than 22.3 Å 3 could be accommodated in 1 leading to the solvatochromic photoluminescence (PL). The mechanism of solvatochromic PL was also deeply studied, which was found to be closely related to the supramolecular interactions between solvent molecules and the host material. Different functional groups of the solvent molecule can affect its strength of hydrogen bonding with [SbCl 5 ] 2–, which is crucial for the distortion level of [SbCl 5 ] 2– unit and thus results in not only distinct…

Photocatalytic CO 2 reduction reaction is believed to be a promising approach for CO 2 utilization. In this work, a noble metal-free photocatalytic system, composed of bis (terpyridine)iron(II) complexes and an organic thermally activated delayed fluorescence compound, has been developed for selective reduction of CO 2 to CO with a maximum turnover number up to 6320, 99.4% selectivity, and turnover frequency of 127 min –1 under visible–light irradiation in dimethylformamide/H 2 O solution. More than 0.3 mmol CO was generated using 0.05 μmol catalyst after 2 h of light irradiation. The apparent quantum yield was found to be 9.5% at 440 nm (180 mW cm –2 ). Control experiments and UV–vis–NIR spectroscopy studies further demonstrated that water strongly promoted the photocatalytic cycle and terpyridine ligands rather than Fe(II) were initially reduced during the photocatalytic process.

Z-scheme g-C 3 N 4 /Ag 3 VO 4 /reduced graphene oxide (rGO) photocatalysts with multi-interfacial electron-transfer paths enhancing CO 2 photoreduction under UV–vis light irradiation were successfully prepared by a hydrothermal process. Transmission electron microscope images displayed that the prepared photocatalysts have a unique 2D–0D–2D ternary sandwich structure. Photoelectrochemical characterizations including TPR, electrochemical impedance spectroscopy, photoluminescence, and linear sweep voltammetry explained that the multi-interfacial structure effectively improved the separation and transmission capabilities of photogenerated carriers. Electron spin resonance spectroscopy and band position analysis proved that the electron-transfer mode of g-C 3 N 4 /Ag 3 VO 4 meets the Z-scheme mechanism. The introduction of rGO provided more electron-transfer paths for the photocatalysts and enhanced the stability of Ag-based semiconductors. In addition, the π–π conjugation effect between g-C 3 N 4 and rGO further improved the generation and separation efficiency of photogenerated…

A series of multichromophoric ruthenium(II) complexes with the formulation [Ru(tpy-BODIPY)(tpy-R)]Cl 2 ( 1 – 4 ), having a heteroleptic Ru(II)-bis-tpy (tpy = 4′-phenyl-2,2′:6′,2″-terpyridine) moiety covalently linked to a boron-dipyrromethene (BODIPY) pendant, have been prepared and characterized and their application as a phototherapeutic and photodetection agent in cancer therapy has been explored. Ligand L 1 with a terpyridine-BODIPY moiety and complex 1 as its PF 6 salt ( 1a ) have been structurally characterized by a single-crystal X-ray diffraction study. Complex 1a has a distorted-octahedral RuN 6 core with a Ru(II)-bis-terpyridine unit that is covalently linked to one photoactive BODIPY unit. The complexes exhibit strong absorbance near 502 nm (ε ≈ (3.7–7.8) × 10 4 M –1 cm –1 ) and high singlet oxygen sensitization ability, giving singlet oxygen quantum yield (Φ Δ ) values ranging from 0.57 to 0.75 in DMSO. An emission-based study using complex 4 and Singlet Oxygen Sensor Green (SOSG) displays the formation of singlet oxygen inside the cells and also in the buffer medium…

Five new anionic aqueous dioxidovanadium(V) complexes, [{VO 2 L 1,2 }A(H 2 O) n ] α ( 1 – 5 ), with the aroylhydrazone ligands pyridine-4-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)hydrazide (H 2 L 1 ) and furan-2-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)hydrazide (H 2 L 2 ) incorporating different alkali metals (A = Na +, K +, Cs + ) as countercation were synthesized and characterized by various physicochemical techniques. The solution-phase stabilities of 1 – 5 were determined by time-dependent NMR and UV–vis, and also the octanol/water partition coefficients were obtained by spectroscopic techniques. X-ray crystallography of 2 – 4 confirmed the presence of vanadium(V) centers coordinated by two cis -oxido-O atoms and the O, N, and O atoms of a dianionic tridentate ligand. To evaluate the biological behavior, all complexes were screened for their DNA/protein binding propensity through spectroscopic experiments. Finally, a cytotoxicity study of 1 – 5 was performed against colon (HT-29), breast (MCF-7), and cervical (HeLa) cancer cell lines and a noncancerous NIH-3T3 cell…

Molybdenum disulfide (MoS 2 ) is intrinsically inert for the hydrogen evolution reaction (HER) in alkaline media due to its electronic structures. Herein, we tune the electronic structures of MoS 2 by a combined strategy of post-N doping coupled with the synergistic effect of Ti 3 C 2 T X . The as-prepared N-doped MoS 2 /Ti 3 C 2 T X heterostructures show remarkable alkaline HER activity with an overpotential of 225 mV at 140 mA cm –2, which ranks the N-doped MoS 2 /Ti 3 C 2 T X heterostructures among the best MoS 2 /MXene-based electrocatalysts reported for alkaline HER. The first-principles calculations indicate that the N doping can enhance the activation of nearby S sites of MoS 2 /Ti 3 C 2 T X and thus promote the HER process. This strategy provides a promising way to develop high-efficiency MoS 2 /MXene heterostructure catalysts for alkaline HER.

Exploring effective electrocatalysts for oxygen evolution reaction (OER) is a crucial requirement of many energy storage and transformation systems, involving fuel cells, water electrolysis, and metal–air batteries. Transition-metal oxides (TMOs) have attracted much attention to OER catalysts because of their earth abundance, tunable electronic properties, and so forth. Defect engineering is a general and the most important strategy to tune the electronic structure and control size, and thus improve their intrinsic activities. Herein, OER performance on spinel CuCo 2 O 4 was greatly enhanced through cation substitution and size reduction. Ce-substituted spinel CuCe δ Co 2−δ O x (δ = 0.45, 0.5 and 0.55) nanoparticles in the quantum dot scale (2–8 nm) were synthesized using a simple and facile phase-transfer coprecipitation strategy. The as-prepared samples were highly dispersed and have displayed a low overpotential of 294 mV at 10 mA·cm –2 and a Tafel slope of 57.5 mV·dec –1, which outperform commercial RuO 2 and the most high-performance analogous catalysts reported. The…

A new porous copper–organic framework assembled from 12-nuclear [Cu 12 ] nanocages {[Cu 2 (L 4– )(H 2 O) 2 ]·4DMA·2H 2 O} n ( 1 ) (H 4 L = 5,5′-(butane-1,4-diyl)-bis(oxy)-diisophthalic acid) was successfully prepared and structurally characterized. Compound 1 feathering of a 3D framework with two types of 1D nanotubular channels and a large specific surface area can effectively enrich various harmful dyes. Additionally, due to the carbon dioxide (CO 2 ) interactions with open Cu(II) sites and the electron-rich ether oxygen atoms of ligand in 1, it exhibits a highly selective CO 2 uptake. Interestingly, 1 can effectively catalyze the cycloaddition reaction of CO 2 with various epoxides under mild conditions, which is ascribed to the Lewis acid Cu(II) sites in the framework of 1 . Importantly, 1 acting as a heterogeneous catalyst can be recycled at least 10 times without an obvious loss of catalytic activity, and the CO 2 cycloaddition mechanism was further uncovered by density functional theory (DFT) calculations. This study can greatly enrich the MOF catalysts system of CO 2…

The built-in electric field generated by polar materials is one of the most effective strategies to promote the separation of photogenerated electron–hole pairs in the field of photocatalysis. However, because of the complexity and diversity of the built-in electric field in polar materials, it is not clear how to enhance the photocatalytic performance and how to control the polar electric field effectively. To this end, four-layered bismuth oxyhalides, BiOX, and BiOXO 3 (X = Br, I) were synthesized by a simple hydrothermal method. X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis confirmed that they all have the structure characteristics of a sillenite phase. Scanning electron microscopy images show that they all have the morphology of nanosheets. Among them, BiOBrO 3 was successfully synthesized and characterized for the first time in the present work. The order of photocatalytic performance (including carrier’s lifetime, photocurrent density, and H 2 evolution rate) of the four compounds is listed as follows: BiOBrO 3 > BiOI…

N,O-hybrid diamide ligands with N-heterocyclic skeletons are one of the promising extractants for the selective separation of actinides over lanthanides in a highly acidic HNO 3 solution. In this work, three hard–soft donor mixed diamide ligands, pyridine-2,6-diylbis(pyrrolidin-1-ylmethanone) (Pyr-PyDA), 2,2′-bipyridine-6,6′-diylbis(pyr-rolidine-1-ylmethanone) (Pyr-BPyDA), and (1,10-phenanthroline-2,9-diyl)bis(pyrrolidin-1-ylmethanone) (Pyr-DAPhen), were synthesized and used to probe the influence of N-heterocyclic cores on the complexation and extraction behaviors with trivalent lanthanides and actinides. 1 H NMR titration experiments demonstrated that 1:1 metal-to-ligand complexes were mainly formed between the three ligands and lanthanides, but 1:2 type complexes were also formed between tridentate Pyr-PyDA and Lu(III). The stability constants (log β) of these three ligands with two typical lanthanides, Nd(III) and Eu(III), were determined through spectrophotometric titration. It is found that Pyr-DAPhen formed the most stable complexes, while Pyr-PyDA formed the most unstable…

Emission of harmful pollutants from different sources into the environment is a major problem nowadays. Organochlorine pesticides such as DDT (C 14 H 9 Cl 5 ) are toxic, bio-accumulative, and regularly seen in water bodies, air, biota, and sediments. Various systems can be considered for minimizing the DDT (dichloro-diphenyl-trichloroethane) pollution. However, due to simplicity and acceptability, the adsorption method is the most popular method. Adsorption is gradually employed for the removal of both organic and inorganic pollutants found in soil and water. Thus, in this regard, efforts are being made to design inorganic nanoclusters (B 12 N 12 ) encapsulated with late transition metals (Zn, Cu, Ni, Co, and Fe) for effective adsorption of DDT. In this context, detailed thermodynamics and quantum chemical study of all the designed systems have been carried out with the aid of density functional theory. The adsorption energy of DDT on metals cocooned in a nanocluster is found to be higher, and better adsorption energy values as compared to that of the pristine B 12 N 12 -DDT…

The efficiency of the hydrogen evolution reaction (HER) can be facilitated by the presence of proton-transfer groups in the vicinity of the catalyst. A systematic investigation of the nature of the proton-transfer groups present and their interplay with bulk proton sources is warranted. The HERs electrocatalyzed by a series of iron porphyrins that vary in the nature and number of pendant amine groups are investigated using proton sources whose p K a values vary from ∼9 to 15 in acetonitrile. Electrochemical data indicate that a simple iron porphyrin (FeTPP) can catalyze the HER at this Fe I state where the rate-determining step is the intermolecular protonation of a Fe III -H – species produced upon protonation of the iron(I) porphyrin and does not need to be reduced to its formal Fe 0 state. A linear free-energy correlation of the observed rate with p K a of the acid source used suggests that the rate of the HER becomes almost independent of p K a of the external acid used in the presence of the protonated distal residues. Protonation to the Fe III -H – species during the HER…

Silver vanadate nanorods (β-AgVO 3 ) with silver nanoparticles (Ag-NPs) decorated on the surface of the rods were synthesized by using simple hydrothermal technique and later anchored onto nitrogen-doped reduced graphene oxide (N-rGO) to make a novel nanocomposite. Experimental analyses were carried out to identify the electronic configuration by X-ray diffraction analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis, which revealed monoclinic patterns of the C 12/ m 1 space group with Wulff construction forming beta silver vanadate (β-AgVO 3 ) crystals with optical density and phase transformations. Ag nucleation showed consistent results with metallic formation and electronic changes occurring in [AgO 5 ] and [AgO 3 ] clusters. Transmission electron microscopy and field-emission scanning electron microscopy with elemental mapping and EDX analysis of the morphology reveals the nanorod structure for β-AgVO 3 with AgNPs on the surface and sheets for N-rGO. Additionally, a novel electrochemical sensor is constructed by using Ag/AgVO 3 /N-rGO…

This Viewpoint brings awareness of the challenges and subsequent breakthroughs at the intersection of different disciplines, illustrated by the example of the influence biological entities exerted on a huge class of inorganic coordination compounds, called polyoxometalates (POMs). We highlight the possible effects of biological systems on POMs that need to be considered, thereby emphasizing the depth and complexity of interdisciplinary work. We map POMs' structural, electrochemical, and stability properties in the presence of biomolecules and stress the potential challenges related to inorganic coordination chemistry carried out in biological systems. This Viewpoint shows that new chemistry is available at the intersections between disciplines and aims to guide the community toward a discussion about current as well as future trends in truly interdisciplinary work.

Different metal–organic units were introduced into the {PMo 12 } polyoxometalate (POM) system to yield three porous coordination polymers with distinct characteristics, {Cu(pra) 2 }[{Cu(pra) 2 } 3 {PMo 11 VI Mo V O 40 }] ( 1 ), [{Ag 5 (pz) 6 (H 2 O) 0.5 Cl}{PMo 11 VI Mo V O 40 }] ( 2 ), and [{Cu 3 (bpz) 5 (H 2 O)}{PMo 12 O 40 }] ( 3 ) (pra = pyrazole; pz = pyrazine; bpz = benzopyrazine), via an in situ hydrothermal method. In comparison with the maternal Keggin cluster and most reported POM electrode materials, compounds 1 – 3 exhibit larger specific capacitances (672.2, 782.1, and 765.2 F g –1 at a current density of 2.4 A g –1, respectively), superior cyclic stability (91.5%, 89.3%, and 87.8% of cycle efficiency after 5000 cycles, respectively), and boosted conductivity, which may be attributed to the introduction of metal–organic units. The result indicates that metal–organic units can effectively enhance the capacitance performance of POMs. This may be due to the fact that they provide additional redox centers, induce the formation of stable porous structures, and improve…

The development of porous materials for ethylene (C 2 H 4 ) separation and purification, a very important separation process in the chemical industry, is urgently needed but quite challenging. In particular, the realization of selectivity-reversed adsorption (namely, C 2 H 4 is not preferentially adsorbed) and the simultaneous capture of multinary coexisting impurities such as ethane (C 2 H 6 ) and acetylene (C 2 H 2 ) will significantly simplify process design and reduce energy and cost consumption, but such porous materials are quite difficult to design and have not yet been fully explored. In this work, by employing an aromatic-rich bithiophene-based tetraisophthalate ligand, we solvothermally fabricated an anionic In(III)-based framework termed ZJNU-115 featuring In(COO) 4 as an inorganic secondary building unit as well as one-dimensional channels. Due to the absence of unsaturated metallic sites, together with aromatic-rich channel surface decorated with abundant hydrogen-bonding acceptors of carboxylate oxygen and thiophene sulfur atoms, desolvated ZJNU-115 exhibited an…

The structural design of multiple functional components could integrate synergistic effects to enhance the catalytic performance of MoS 2 -based composites for catalytic applications. Herein, one-dimensional (1D) Co-MoS 2 /Pd@NCMTs composites were designed to prepare Co-doped MoS 2 /Pd nanosheets (NSs) on N-doped carbon microtubes (NCMTs) from tubular polypyrrole (PPy) as multifunctional catalysts. The Co-MoS 2 /Pd@NCMTs composites integrated the synergistic effects of Co-doping, a 1D tubular structure, and noble-metal Pd decoration. Thus, a higher catalytic activity was observed in 4-nitrophenol (4-NP) reduction and peroxidase-like catalysis than other components, such as MoS 2, MoS 2 @NCMTs, and Co-MoS 2 @NCMTs. Remarkably, the results indicated that the dissolution, diffusion, and redistribution led to the dissolution of MoO 3 @ZIF-67 cores and generation of Co-doped MoS 2 NSs. Benefiting from the synergistic effect from these components, Co-MoS 2 /Pd@NCMTs were considered as a facile colorimetric sensing platform for detecting tannic acid. Moreover, outstanding performance was…

Functionalizing metal–organic frameworks (MOFs) with amines is a commonly used strategy to enhance their performance in CO 2 capture applications. As such, in this work, a two-step strategy to covalently functionalize NH 2 -containing MOFs with short chain polyamines was developed. In the first step, the parent MOF, Zn 4 O(NH 2 -BDC) 3, was exposed to bromoacetyl bromide (BrAcBr), which readily reacts with pendant -NH 2 groups on the 2-amino-1,4-benzenedicarboxylate (NH 2 -BDC 2– ) ligand. 1 H NMR of the digested MOF sample revealed that as much as 90% of the MOF ligands could be functionalized in the first step. Next, the MOF samples 60% of the ligands functionalized with acetyl bromide, Zn 4 O(NH 2 -BDC) 1.2 (BrAcNH-BDC) 1.8, was exposed to several short chain amines including ethylenediamine (ED), diethylenetriamine (DETA), and tris(2-aminoethyl)amine (TAEA). Subsequent digested 1 H NMR analysis indicated that a total of 30%, 28%, and 19% of the MOF ligands were successfully grafted to ED, DETA, and TAEA, respectively. Next, the CO 2 adsorption properties of the amine grafted…

We report a series of seven cationic heteroleptic copper(I) complexes of the form [Cu(P^P)(dmphen)]BF 4, where dmphen is 2,9-dimethyl-1,10-phenanthroline and P^P is a diphosphine chelate, in which the effect of the bite angle of the diphosphine ligand on the photophysical properties of the complexes was studied. Several of the complexes exhibit moderately high photoluminescence quantum yields in the solid state, with Φ PL of up to 35%, and in solution, with Φ PL of up to 98%. We were able to correlate the powder photoluminescence quantum yields with the % V bur of the P^P ligand. The most emissive complexes were used to fabricate both organic light-emitting diodes and light-emitting electrochemical cells (LECs), both of which showed moderate performance. Compared to the benchmark copper(I)-based LECs, [Cu(dnbp)(DPEPhos)] + (maximum external quantum efficiency, EQE max = 16%), complex 3 (EQE max = 1.85%) showed a much longer device lifetime ( t 1/2 = 1.25 h and >16.5 h for [Cu(dnbp)(DPEPhos)] + and complex 3, respectively). The electrochemiluminescence (ECL) properties of several…

Color-tunable phosphors can be obtained through codoping strategies and energy transfer regulation. Ce 3+ and Eu 2+ are the most common and effective activator ions used in phosphor materials. However, the energy transfer from Eu 2+ to Ce 3+ is rarely reported. In this work, Y 2 Mg 2 Al 2 Si 2 O 12 (YMAS):Eu 2+,Ce 3+ phosphors were successfully synthesized, which was confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Rietveld refinement, scanning electron microscopy (SEM) and element mapping images, and spectral information. The luminescent color of YMAS:Eu 2+,Ce 3+ phosphors could be tuned from blue to cyan to light green to yellow-green and finally to green-yellow, which was achieved by adjusting the energy transfer between different dopants. The energy transfer from Eu 2+ to Ce 3+ was confirmed by photoluminescence spectra and fluorescence decay curves. Within the experimental gradient, the energy transfer efficiency could reach up to 48%. At 373 K, the Y 1.99 Mg 1.99 Al 2 Si 2 O 12:0.01Eu 2+,0.01Ce 3+ (YMAS:0.01Eu 2+,0.01Ce 3+ ) phosphor exhibited a…

High Resolution Image Download MS PowerPoint Slide The development of cost-effective, functional materials that can be efficiently used for sustainable energy generation is highly desirable. Herein, a new molecular precursor of bismuth (tris(selenobenzoato)bismuth(III), [Bi(SeOCPh) 3 ]), has been used to prepare selectively Bi or Bi 2 Se 3 nanosheets via a colloidal route by the judicious control of the reaction parameters. The Bi formation mechanism was investigated, and it was observed that the trioctylphosphine (TOP) plays a crucial role in the formation of Bi. Employing the vapor deposition method resulted in the formation of exclusively Bi 2 Se 3 films at different temperatures. The synthesized nanomaterials and films were characterized by p-XRD, TEM, Raman, SEM, EDX, AFM, XPS, and UV–vis spectroscopy. A minimum sheet thickness of 3.6 nm (i.e., a thickness of 8–9 layers) was observed for bismuth, whereas a thickness of 4 nm (i.e., a thickness of 4 layers) was observed for Bi 2 Se 3 nanosheets. XPS showed surface oxidation of both materials and indicated an uncapped surface of…

Fast-charged energy-storage technologies have become important nowadays as they are required by many applications, including automobiles. This inspires the exploitation of hybrid supercapacitors (HSCs) with the advantages of fast charge offered by the capacitor characters and high energy density from the property of battery technology. The challenges lay in the construction of advanced materials with high pseudocapacitive activity. Herein, a metal–organic framework derivative is utilized to address the problems. Specifically, polyhedral CoNi layered double hydroxide (CoNi-LDH x ) cages assembled in the form of nanosheet arrays are prepared from ZIF-67 using a facile ion-exchange approach. Based on the control over the mass ratio of ZIF-67 to Ni salt, the optimal CoNi-LDH 2 is attained. It exhibits ultrahigh capacities ranging from 1031.4 to 667.3 C g –1 under 1–25 A g –1, thanks to rich Faradaic active spots and the accelerated kinetics provided by the synergy between nanosheet arrays and the hollow structure. The CoNi-LDH 2 -based HSC with the gel electrolyte shares remarkable…

The exquisite combination of Ba 2+ and Zn 2+ with the aid of 2,4,6-tri(2,4-dicarboxyphenyl)pyridine (H 6 TDP) under the condition of solvothermal self-assembly generates one highly robust [Ba 3 Zn 4 (CO 2 ) 12 (HCO 2 ) 2 (OH 2 ) 2 ]–organic framework of {[Ba 3 Zn 4 (TDP) 2 (HCO 2 ) 2 (OH 2 ) 2 ]·7DMF·4H 2 O} n ( NUC-27 ), in which adjacent 2D layers are interlaced via hydrogen-bonding interactions to form a 3D skeleton with peapod-like channels and nano-caged voids. It is worth emphasizing that both Ba 2+ and Zn 2+ ions in NUC-27 display the extremely low coordination modes: hexa-coordinated [Ba(1)] and tetra-coordinated [Ba(2), Zn(1), and Zn(2)]. Furthermore, to the best our knowledge, NUC-27 is one scarcely reported 2D-based nanomaterial with an unprecedented Z-shaped hepta-nuclear heterometallic cluster of [Ba 3 Zn 4 (CO 2 ) 12 (HCO 2 ) 2 (OH 2 ) 2 ] as SBUs, which not only has plentiful low-coordinated open metal sites but also has the excellent physicochemical properties including omni-directional opening pores, ultrahigh porosity, larger specific surface area, and the…

Development of a low-cost transition metal-based catalyst for water splitting is of prime importance for generating green hydrogen on an industrial scale. Recently, various transition metal-based oxides, hydroxides, sulfides, and other chalcogenide-based materials have been synthesized for developing a suitable anode material for the oxygen evolution reaction (OER). Among the various transition metal-based catalysts, their oxides have received much consideration for OER, especially in lower pH condition, and MnO 2 is one of the oxides that have widely been used for the same. The large variation in the structural disorder of MnO 2 and internal resistance at the electrode–electrolyte interfaces have limited its large-scale application. By considering the above limitations of MnO 2, here in this work, we have designed Ni-doped MnO 2 via a simple wet-chemical synthetic route, which has been successfully applied for OER application in 0.1 M KOH solution. Doping of various quantities of Ni into the MnO 2 lattices improved the OER properties, and for achieving 10 mA/cm 2 current density,…

Catalytic transformation of levulinic acid (LA) to γ-valerolactone (γ-GVL) is an important route for biomass upgradation. Because both Bro̷nsted and Lewis acidic sites are required in the cascade reaction, herein we fabricate a series of H 3 PW 12 O 40 @Zr-based metal–organic framework ( [email protected] ) by a facile impregnation method. The synthesized [email protected] is active for the conversion of LA to γ-GVL using isopropanol as a hydrogen donor. Interestingly, with the increase in the HPW loading amount, the yield of γ-GVL increases first and then decreases, and 14% [email protected] gave the highest γ-GVL yield (86%). The excellent catalytic performance was ascribed to the synergistic effect between the accessible Lewis acidic Zr 4+ sites in MOF-808 and Bro̷nsted acidic HPW sites. Based on the experimental results, a plausible reaction mechanism was proposed: the Zr 4+ sites catalyze the transfer hydrogenation of carbonyl groups and the HPW clusters promote the esterification of LA with isopropanol and lactonization to afford γ-GVL. Moreover, [email protected] is resistant…

Uniform, well-defined cadmium sulfide@cadmium selenide core/shell quantum dots (CdS@CdSe QDs) were, for the first time, successfully synthesized by a solvothermal method and chemical bath growth for photoelectrochemical activities. The as-synthesized CdS@CdSe QDs not only exhibit superior self-powered photoresponse behavior and excellent stability under ambient conditions but also display significantly improved current densities and photoresponsivity compared to those of individual CdS QDs or CdSe QDs, mainly due to the built-in electric field, and thus have great potential in the fields of renewable energy and renewable energy consumption for carbon neutrality target achievement.

A systematic high-pressure study of the CdN x ( x = 2, 3, 4, 5, and 6) system is performed by using the first-principles calculation method in combination with the particle swarm optimization algorithm. We proposed four stable high-pressure phases ( P 4 mbm -CdN 2, Cmmm -CdN 4, I 4̅2 d -CdN 4, and C 2/ c -CdN 5 ) and one metastable high-pressure phase ( C 2/ m -CdN 6 ), for which the structural frames are composed of a diatomic quasi-molecule N 2, standard armchair N-chain, S-type bent armchair N-chain, zigzag–antizigzag N-chain, and N 14 network structure. Among them, the novel zigzag–antizigzag N-chain and N 14 network structure are reported for the first time. More importantly, Cmmm -CdN 4 and C 2/ m -CdN 6 possess high stability under ambient conditions, which may be quenched to ambient conditions once they are synthesized at high-pressure conditions. The high decomposition energy barrier (1.14 eV) results in a high decomposition temperature (2500 K) of Cmmm -CdN 4, while a low decomposition energy barrier (0.19 eV) results in a mild decomposition temperature (500 K) of C 2/ m…

The construction of a phase junction photocatalyst can significantly enhance the photocatalytic performance with high selectivity for CO 2 reduction. In this study, an S-scheme junction Cd 0.5 Zn 0.5 S/CoWO 4 semiconductor with the coupling of a twin crystal Cd 0.5 Zn 0.5 S homojunction and CoWO 4 was designed through a hydrothermal method, which could convert CO 2 to CO with high efficiency under visible-light illumination. Cd 0.5 Zn 0.5 S–10%CoWO 4 exhibited the optimal performance and its CO yield and selectivity were up to 318.68 μmol·g –1 and 95.90%, respectively, which were 4.54 and 1.62 times higher than that of twin crystal Cd 0.5 Zn 0.5 S. Moreover, the Cd 0.5 Zn 0.5 S homojunction with a zinc-blende and wurtzite phase and the S-scheme phase junction of Cd 0.5 Zn 0.5 S/CoWO 4 enhanced the property of CO 2 adsorption and accelerated the detachment of photogenerated carriers. The combination of photogenerated holes in Cd 0.5 Zn 0.5 S and the electrons of CoWO 4 can retain the reduction sites to improve photocatalytic performance. This study provides a neoteric concept and…

Transition-metal phosphides and sulfides are considered as promising cocatalysts for the photocatalytic hydrogen evolution reaction (HER), and the cocatalytic effect can be improved by directed heterostructure engineering. In this study, a novel lattice-matched CoP/CoS 2 heterostructure having a nanosheet morphology was developed as an HER cocatalyst and integrated in situ onto graphitic carbon nitride (g-C 3 N 4 ) nanosheets via a successive phosphorization and vulcanization route. First-principles density functional theory calculations evidenced that the construction of the lattice-matched CoP/CoS 2 heterostructure resulted in the redistribution of interface electrons, enhanced metallic characteristics, and improved H* adsorption. As a result of these effects, the CoP/CoS 2 heterostructure cocatalyst formed a 2D/2D Schottky junction with the g-C 3 N 4 nanosheets, thus promoting photoelectron transfer to CoP/CoS 2 and realizing fast charge-carrier separation and good HER activity. As expected, the CoP/CoS 2 heterostructure exhibited excellent cocatalytic activity, and the optimal…

On the basis of the global warming effect, it is of great significance to convert CO 2 into the high value-added products oxazolidinones, but investigations on main-group-based metal–organic frameworks (MOFs) as heterogeneous catalysts still have not been reported so far. In this work, a quadruple-interpenetrated porous indium-based MOF, {[NH 2 (CH 3 ) 2 ][In(CPT) 2 ]·3CH 3 CN·3DMA} n ( 1 ), is constructed from the organic ligand 3,5-bis(4′-carboxyphenyl)-1,2,4-triazole through solvothermal reactions, and N 2 adsorption proves that the framework has a high Brunauer–Emmett–Teller surface areas with 2024 m 2 /g. The catalytic research on CO 2 conversion reveals that compound 1 has high reactivity for the cycloaddition of CO 2 with aziridines, and the product 3-ethyl-5-phenyloxazolidin-2-one can be obtained with a yield of 99% under mild conditions. In addition, 1 exhibits excellent activity for different kinds of substrates and can be reused at least five cycles without any significant deactivation, suggesting that 1 is a potential candidate for the chemical conversion of CO 2 and…

The generation of smart responsive materials that can perform multiple drastic optical outputs upon different triggers provides a good platform to encode and hide the information and create multilevel security. In this paper, a smart multiresponsive MOF-on-MOF material was reported using one MOF ( HPU-14 ) as a platform to grow ZIF-8 on the outer layer, combining different emitter centers such as anthracene (ANT) and lanthanide ions (Ln 3+ ) confined into two MOFs. Due to the existence of ANT in the pores of ZIF-8, this composite material can exhibit reversible photoswitching behavior under a 365 nm ultraviolet (UV) lamp and enable “resetting and reusing” dynamic anticounterfeiting application. Meanwhile, when treated by an acid/alkali gas, this material can also display reversible switching behavior under 254 nm UV irradiation, which is attributed to the loading of Ln 3+ on HPU-14 . We demonstrated that this excellent practical anticounterfeiting material can decipher the right information only by following a strict stimuli sequence. Therefore, this MOF-on-MOF material synthesis…

The coupling reaction of propargylic amines and carbon dioxide (CO 2 ) to synthesize 2-oxazolidinones is an important reaction in industrial production, and yet harsh reaction conditions and noble-metal catalysts are often required to achieve high product yields. Herein, one novel noble-metal-free three-dimensional framework, [Mg 3 Cu 2 I 2 (IN) 4 (HCOO) 2 (DEF) 4 ] n ( 1 ), assembled by magnesium and copper clusters was synthesized and applied to this reaction. Compound 1 displays excellent solvent stability. Importantly, 1, acting as heterogeneous catalyst, can highly catalyze the cyclization of propargylic amines with CO 2 under atmospheric pressure at room temperature, which can be recycled at least five times without an obvious decrease of the catalytic activity. NMR spectroscopy, coupled with 13 C-isotope- and deuterium-labeling experiments, clearly clarifies the mechanism of this catalytic system: CO 2 was successfully captured and converted to the product of 2-oxazolidinones, the C≡C bond of propargylic amines can be effectively activated by 1, and proton transfer was…

The search for nonlinear optical (NLO) crystals with excellent comprehensive properties is a formidable challenge. In this work, two guanidine antimony fluorides, C(NH 2 ) 3 Sb 2 F 7 and C(NH 2 ) 3 SbF 4, were obtained by conjunction of [C(NH 2 ) 3 ] groups with π-conjugated configuration and stereochemically active Sb 3+ cations. Due to the different coordination modes of Sb–F bonds and H–F hydrogen bonds, the crystal structure of C(NH 2 ) 3 Sb 2 F 7 is centrosymmetric (CS), while C(NH 2 ) 3 SbF 4 is noncentrosymmetric (NCS). Optical measurements show that the UV cutoff wavelengths of the title compounds were both less than 240 nm. Thermal studies indicate that these crystals are stable up to 250 °C. In addition, the second harmonic generation (SHG) response of C(NH 2 ) 3 SbF 4 is 2 times that of KH 2 PO 4 (KDP) with the phase-matchable capacity. Theoretical calculations reveal that the large SHG effects of C(NH 2 ) 3 SbF 4 were attributed to the synergy between the planar [C(NH 2 ) 3 ] units and the distorted [SbF 4 ] groups. These results demonstrate that the guanidine antimony…

Plasmonics, especially the localized surface plasmon resonance (LSPR) in non-noble metal bismuth nanoparticles (Bi NPs), and its spectral features and applications have stimulated increasing research interest in recent years. However, the lack of mature methods to prepare Bi NPs with a well-controlled size and/or shape significantly limits the experimental investigations concerning the LSPR optical properties. Herein, we realize the size-tunable synthesis of nearly monodisperse spherical Bi NPs through a thiolate pyrolysis reaction in solution. The instantaneous thermolysis of a layered molecular intermediate, bismuth dodecanethiolate [Bi(SC 12 H 25 ) 3 ], results in a classical LaMer mechanism for the nucleation and growth of Bi NPs, allowing for a precise size control from 65 to 205 nm in the average diameter. The diameter tunability enables a systematic study on the size dependence of LSPR optical properties of Bi NPs, and we observe rich ultraviolet–visible–near-infrared spectral responses arising from the LSPR absorption and scattering of Bi NPs as their size varies, which will…

Bi 3+ /Te 4+ co-doped Cs 2 SnCl 6 with dual emission spectrum (i.e., 450 and 575 nm) was achieved by a modified solution method, which can overcome the phase separation in the previous method for Cs 2 SnCl 6 crystal growth. The two emission peaks arising from the two dopants Bi 3+ and Te 4+ have distinct photoluminescence (PL) lifetimes. Thus, the control of dopant ratio or PL delay time will regulate the PL intensity ratio between 450 and 575 nm peaks leading to adjustable emission color. The energy transfer between the two emission centers, which is confirmed by the optical spectra and PL lifetime, has a critical distance around 7.8 nm with a maximum of 50% transfer efficiency. The Bi 3+ /Te 4+ co-doped Cs 2 SnCl 6 with superior stability in water and aqua regia was fabricated into a single-phase white light-emitting diode. In the meantime, various luminescent heterostructures were obtained by epitaxial Cs 2 SnCl 6 crystal growth with different dopants, which can broaden the study of composition engineering in halide perovskites.

Metal–organic framework (MOF)-based materials have attracted attention in recent times owing to their remarkable properties such as regulatable pore size, high specific surface area, and elasticity in their network topology, geometry, dimension, and chemical functionality. It is believed that the incorporation of a MOF network into a fibrous matrix results in the improvement of the electrocatalytic properties of the material. Herein, we have synthesized a Co-incorporated MOF-5-based fibrous material by a simple wet-chemical method, followed by an electrospinning (ES) process. The as-prepared Co-incorporated MOF-5 microfibers were employed as an electrocatalyst for the oxygen evolution reaction (OER) in 1 M KOH electrolyte. The catalyst demands a lower overpotential of 240 mV to attain a current density of 10 mA/cm 2 with a lower Tafel slope value of 120 mV/dec along with a charge transfer resistance value of 2.9 Ω from electron impedance spectroscopy (EIS) analysis. From these results, it has been understood that the incorporation of Co metal into the MOF-5 microfibrous network has…

Ammonia (electro)oxidation with molecular catalysts is a rapidly developing topic with wide practical applications ahead. We report here the catalytic ammonia oxidation reaction (AOR) activity using [Ru(tda-κ-N 3 O)(py) 2 ], 2, (tda 2– is 2,2′:6′,2′′-terpyridine-6,6′′-dicarboxylate; py is pyridine) as a catalyst precursor. Furthermore, we also describe the rich chemistry associated with the reaction of Ru-tda and Ru-tPa (tPa –4 is 2,2′:6′,2′′-terpyridine-6,6′′-diphosphonate) complexes with NH 3 and N 2 H 4 using [Ru II (tda-κ-N 3 O)(dmso)Cl] (dmso is dimethyl sulfoxide) and [Ru II (tPa-κ-N 3 O)(py) 2 ], 8, as synthetic intermediates, respectively. All the new complexes obtained here were characterized spectroscopically by means of UV–vis and NMR. In addition, a crystal X-ray diffraction analysis was performed for complexes trans -[Ru II (tda-κ-N 3 )(py) 2 (NH 3 )], 4, trans -[Ru II (tda-κ-N 3 )(N-NH 2 )(py) 2 ], 5, cis -[Ru II (tda-κ-N 3 )(py)(NH 3 ) 2 ], 6 (30%), and cis -[Ru II (tda-k-N 3 )(dmso)(NH 3 ) 2 ], 7 (70%). The AOR activity associated with 2 and 8 as catalyst precursors…

Antibiotics are the most important drugs for people and animals to fight bacterial illnesses. Overuse of antibiotics has had unintended consequences, such as antibiotic resistance and ecosystem eradication owing to toxic chemical discharge, which have a negative influence on the biome. Herein, we report the synthesis of a hollow ellipsoid-shaped yttrium vanadate/graphitic carbon nitride (YVO 4 @CN) nanocomposite by a hydrothermal approach followed by a sonochemical method for the effective detection of dimetridazole (DMZ). The synergic and coupling effect between both the phases offer non-linear cumulative ramifications which can positively enhance the individual properties of the materials under consideration. This positive hybrid effect increases the conductivity, shortens the ion-diffusion pathway, enhances the electron/ion transportation, and provides more active sites and electron-conducting channels. The accurate optimization of the experimental conditions proposes good electrocatalytic activity for the YVO 4 @CN catalyst, exhibiting a good response toward DMZ detection. It…

It is necessary to develop stable and fast multistimuli responsive materials due to the growing demand in our daily life. In this work, a new viologen-based Cd-complex ( 1 ) exhibits multiple thermochromic and photochromic behaviors through 10 states with 7 colors. For example, it responds to both Cu Kα/Mo Kα X-ray sources and UV dual light quickly with a color change from colorless to dark blue ( 1X ) (Cu Kα/Mo Kα X-ray sources) and cyan ( 1-UV ) (UV light), respectively. Interestingly, it exhibits a three-step coloration phenomenon when heated, which is unprecedented in viologen compounds. Crystal 1 undergoes a color change to pink, blue, and brown under 130, 180, and 240 °C, respectively. In addition, upon fumigation, both 1P and 1Q undergo a decoloration process to colorless ( 1K ) and yellow ( 1T ), respectively. Four more states ( 1P, 1K, 1T, and 1O ) obtained via dehydration–hydration treatment are all photochromic. More importantly, via single-crystal–single-crystal transformation (SC–SC), the photochromic and thermochromic behaviors of 1 were investigated from the molecular…

In this study, two substituent-group-modifying tetracarboxylate ligands, 2′,5′-dimethoxy-[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid (H 4 TPTC-2OMe) and 2′,5′-dimethyl-[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid (H 4 TPTC-2Me), with similar geometries were used as the organic linkers to construct isostructural lanthanide metal–organic frameworks (LnMOFs). The as-prepared LnTPTC-2OMe and LnTPTC-2Me were structurally elucidated by means of single-crystal and powder X-ray diffraction in addition to thermogravimetric analysis and were assessed as luminescence ratiometric thermometers by obtaining the temperature dependence of the luminescence behaviors. We found that both the single lanthanide EuTPTC-2OMe and the dual lanthanide Eu 0.05 Tb 0.95 TPTC-2Me exhibited a distinct S-type luminescence response to temperatures in the range from 313 to 473 K, and their ratiometric parameters can be understood on the basis of the classic Mott–Seitz model. Energy transfers from the ligand to Tb 3+ (or Eu 3+ ) and from Tb 3+ to Eu 3+ in these two systems were investigated…

A polyoxovanadate-based nickel–organic framework, [Ni(bib) 2 ]{V 2 O 6 }({V 6 }-MOF, bib = 1,4-bis(1 H -imidazoly-1-yl)benzene), was facilely prepared under gentle hydrothermal conditions and structurally characterized. Single-crystal X-ray diffraction analysis indicates that the {V 6 } cluster in the {V 6 }-MOF is constructed of two VO 5 tetragonal pyramids and four VO 4 tetrahedrons via the apex sharing of O atoms, presenting a hollow Linqvist-like structure, which is different from these reported hexanuclear vanadium clusters. The {V 6 }-MOF not only expands the structure of polyoxovanadates (POVs) but also catalyzes the rapid detoxification of mustard gas simulant (2-chloroethyl ethyl sulfide, CEES) at 25 °C. The catalytic results were determined by means of GC, GC–MS, and 1 H NMR. Using {V 6 }-MOF as a heterogeneous catalyst, CEES underwent catalyzed oxidation to only nontoxic product 2-chloroethyl ethyl sulfoxide (CEESO) within 40 min, and the conversion and selectivity were almost 100%. In addition, {V 6 }-MOF exhibits high sustainability, and no obvious reductions in…

On account of the strong oxidizing property of the europium(III) ion, its charge transfer band (CTB) can be easily formed in many inorganic compounds. In this work, the Eu 3+ ions were singly doped into the K 3 LuSi 2 O 7 compound with a hexagonal structure, and two kinds of Eu 3+ -O 2– CTBs were detected by monitoring at specific wavelengths. The qualitative analysis of Eu 3+ ion site occupation was illuminated by combining Eu 3+ -O 2– CTBs with the corresponding cell volume. Furthermore, the two kinds of Eu 3+ sites are eventually assigned to the K(2) and Lu sites, which means that Eu 3+ ions selectively occupy the site with a low coordination number, according to the calculated CT energy by the dielectric theory of complex crystals and the magnitude of CT energy in the excitation spectra. Meanwhile, at high temperatures, the CTB does not show the traditional thermal quenching like f–f transitions but demonstrates thermal enhancement; thus, by using this opposite variation in excitation spectra, a noninvasive optical thermometer is presented, and this opposite variation tendency…

It remains a challenge to exploit dual-functional metal–organic frameworks (MOFs) for applications, including luminescence detection and proton conduction. With the deliberate selection of the bifunctional organic ligand 5-sulfoisophthalic acid monosodium salt (NaH 2 bts), and the phosphonic acid ligand N, N ′-piperazine (bismethylenephosphonic acid; H 4 L), a robust three-dimensional (3D) noninterpenetrating dual-functional MOF, [Tb(H 2 L)(H 2 bts)(H 2 O)]·H 2 O ( 1 ), has been synthesized hydrothermally. On the basis of the excellent thermal and chemical as well as superior luminescence stabilities in water and solutions with different pHs, 1 can serve as the simple, rapid, and highly selective and sensitive luminescence detection of the carcinoid biomarkers 5-hydroxytryptamine (HT) and its metabolite 5-hydroxyindole-3-acetic acid (HIAA) with detection limits of nanomolar magnitude in water and in simulated blood plasma and urine systems. Due to the change in the signals that could be readily differentiated by the naked eye under a UV lamp, a portable test paper has been…

A phase-pure nickel bismuth tantalate with pyrochlore structure was synthesized by a solid-phase synthesis method for the first time. The crystal structure of pyrochlore (refined formula Bi 1.58 Ni 0.60 Ta 1.40 O 7, sp. gr. Fd -3 m, a = 10.5343 Å, Z = 8) was clarified by the Rietveld method on the basis of X-ray powder diffraction (XRD) data. The crystallite size determined by the Scherrer method is ∼46 nm. The sample has an atypical pink-purple color. The electronic state of the atoms was investigated by XPS. According to XPS analysis, bismuth atoms have an effective charge of +3; nickel atoms, +(2 + δ); tantalum ions, +(5 – δ). The thermal expansion coefficient of the cell is calculated from high-temperature X-ray measurements in the range of 30–1200 °C. The thermal expansion coefficient (TEC) increases monotonically from 3.79 × 10 –6 °C –1 (30 °C) to 8.32 × 10 –6 °C –1 (990 °C). Above 1080 °C, the TEC decreases due to the thermal dissociation of pyrochlore with new NiTa 2 O 6 phase formation. Ni-doped bismuth tantalate refers to dielectrics and exhibits a moderately high…

Bismuth ion-doped phosphate crystals have shown rich luminescence phenomena. However, the complexity and variety of Bi 3+ -related transitions bring great challenges to the understanding of the underlying mechanisms, rendering it hard to rationally design new phosphors and optimize their performance. In this work, we perform first-principles calculations based on the generalized gradient approximation of density functional to obtain the excited state equilibrium geometric structures and then calculate the electronic structures for various Bi 3+ -related excited states in phosphates RPO 4:Bi 3+ (R = Y, Lu, La) by utilizing the hybrid density functional method. The experimentally measured excitation and emission features are well interpreted by our theoretical calculations. Specifically, we reveal that the emission in LaPO 4:Bi 3+ is of charge transfer nature, whereas the dominant emission in YPO 4:Bi 3+ or LuPO 4:Bi 3+ is the characteristic A band emission. Trapped holes above the valence band maximum due to intrinsic defects are deemed to play a role in the charge-transfer emission…

Introducing stereochemically active lone-pair Sb 3+ cations into sulfates, two three-dimensional (3D) antimony-sulfates, Sb 4 O 5 SO 4 ( 1 ) and Sb 4 O(SO 4 )(OH) 2 ( 2 ), were achieved under moderate hydrothermal conditions. Both structures are constructed by tetranuclear-{Sb 4 }-clusters-based layers and SO 4 tetrahedra. However, owing to the different packing patterns of the layers, they display different characteristics: 1 exhibits a centrosymmetric structure while 2 possesses a noncentrosymmetric structure. UV–vis spectra show that they possess wide band gaps. Sb 4 O(SO 4 )(OH) 2 is nonlinear optical (NLO) active with a second-harmonic generation (SHG) response of ∼1.2 times of KH 2 PO 4, together with the phase-matchable capacity, endowing it a promising UV NLO material. The first-principle calculations were performed to elucidate the structure–property relationships. The results indicate that the lone pair stereoactivity of Sb 3+ provides the large contribution to the macroscopic SHG effect.

Herein, we reported a facile strategy for the preparation of trifunctional ionic metal–organic frameworks (MOFs) incorporating imidazolium cation functionalities. This strategy exploits the Debus–Radziszewski reaction to create the cationic imidazole ring by postsynthetic modification, meanwhile introducing exchangeable counteranions. On the basis of this strategy, MIL-101-IMOH-Br – has been synthesized, which combines Lewis acidic sites, Brønsted acidic sites, and nucleophilic centers to achieve catalysis for the carbon dioxide–epoxide cycloaddition into cyclocarbonate without any cocatalyst and solvent.

8-Arylnaphthyl substituents are privileged motifs frequently integrated into late-transition-metal catalysts, endowing them with an ability to retard chain transfer in ethylene polymerization. In this contribution, we disclose a sort of novel α-diiminenickel and -palladium complexes containing flexible 8-alkylnaphthyl in lieu of rigid 8-arylnaphthyl and their catalytic performance in ethylene polymerization. An interesting feature of these 8-alkylnaphthyl-substituted α-(diimine)PdMeCl complexes is that they present as a mixture of syn and anti isomers (syn:anti = ca. 1:1 ratio, determined by 1 H and 13 C NMR spectroscopy). In ethylene polymerization, these nickel complexes displayed high activity (up to 3.37 × 10 6 g mol –1 h –1 ) and generated branched polyethylenes with broad or bimodal molecular weight distributions (4.6–29.3), while the corresponding palladium complexes exhibited moderate activity, producing highly branched polyethylenes with unimodal and narrow molecular weight distributions (<1.8). In ethylene (E)/methyl acrylate (MA) copolymerization, highly branched E-MA…

Inexpensive and efficient electrocatalysts are crucial for the development and practical application of energy conversion and storage technologies. Layered-double-hydroxide (LDH) materials have attracted much attention due to the special layered structure, but their electrocatalytic activity and stability are still limited. Herein, we propose to tune Co 2+ occupancy and coordination in cobalt-based LDH nanosheets via Fe 3+ doping for efficient and stable electrocatalysis for oxygen evolution reaction (OER). It is found that Fe doping regulates the occupancy and coordination of Co 2+ in CoO 4 tetrahedrons and CoO 6 octahedrons of Co-LDHs. Through density functional theory calculation, we also clarified that Fe 3+ not only modulated the Co 2+ coordination but also functioned as an added catalytic active site. LDH nanosheets with a Co/Fe ratio of 5:1 show a low OER overpotential, much better than the commercial IrO 2, owing to the modulation of Fe 3+ doping on the crystal and electronic structures. After appropriate incorporation of Fe 3+, the almost inactive octahedral coordinated Co…

The front-end of the nuclear fuel cycle encompasses several chemical and physical processes used to acquire and prepare uranium for use in a nuclear reactor. These same processes can also be used for weapons or nefarious purposes, necessitating the need for technical means to help detect, investigate, and prevent the nefarious use of nuclear material and nuclear fuel cycle technology. Over the past decade, a significant research effort has investigated uranium compounds associated with the front-end of the nuclear fuel cycle, including uranium ore concentrates (UOCs), UF 4, UF 6, and UO 2 F 2 . These efforts have furthered uranium chemistry with an aim to expand and improve the field of nuclear forensics. Focus has been given to the morphology of various uranium compounds, trace elemental and chemical impurities in process samples of uranium compounds, the degradation of uranium compounds, particularly under environmental conditions, and the development of improved or new techniques for analysis of uranium compounds. Overall, this research effort has identified relevant chemical and…

Apart from perovskites, the development of different types of pyrochlore oxides is highly focused on various electrochemical applications in recent times. Based on this, we have synthesized pyrochlore-type praseodymium stannate nanoparticles (Pr 2 Sn 2 O 7 NPs) by using a coprecipitation method and further investigated by different analytical and spectroscopic techniques such as X-ray diffraction, Raman spectroscopy, field emission-scanning electron microscopy, high resolution-transmission electron microscopy, and X-ray photoelectron spectroscopy analysis. Followed by this, we have designed a unique and novel electrochemical sensor for nitrofurazone detection, by modifying the glassy carbon electrode (GCE) with the prepared Pr 2 Sn 2 O 7 NPs. For that, the electrochemical experiments were performed by using cyclic voltammetry and differential pulse voltammetry techniques. The Pr 2 Sn 2 O 7 NPs modified GCE exhibits high sensitivity (2.11 μA μM –1 cm –2 ), selectivity, dynamic linear ranges (0.01–24 μM and 32–332 μM), and lower detection limit (4 nM). Furthermore, the Pr 2 Sn 2 O 7…