The 100 most-cited articles in Chemistry - A European Journal, 2023

Selenium, originally described as a toxin, turns out to be a crucial trace element for life that appears as selenocysteine and its dimer, selenocystine. From the point of view of drug developments, selenium-containing drugs are isosteres of sulfur and oxygen with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. In this article, we have focused on the relevant features of the selenium atom, above all, the corresponding synthetic approaches to access a variety of organoselenium molecules along with the proposed reaction mechanisms. The preparation and biological properties of selenosugars, including selenoglycosides, selenonucleosides, selenopeptides, and other selenium-containing compounds will be treated. We have attempted to condense the most important aspects and interesting examples of the chemistry of selenium into a single article.

(Hetero)arenes continue to prove their indispensability in pharmaceuticals, materials science, and synthetic chemistry. As such, the controllable modification of biologically significant (hetero)arenes towards diverse more-potent complex molecular scaffolds through peripheral and skeletal editing has been considered a challenging goal in synthetic organic chemistry. Despite many excellent reviews on peripheral editing (i. e., C-H functionalization) of (hetero)arenes, their skeletal editings via single atom insertion, deletion, or transmutations have received less attention in the review literature. In this review, we systematically summarize the state-of-the-art skeletal editing reactions of (hetero)arenes using carbenes, with a focus on general mechanistic considerations and their applications in natural product syntheses. The potential opportunities and inherent challenges encountered while developing these strategies are also highlighted.

The use of metalated (aza)bicyclo[1.1.0]butanes in synthesis is currently experiencing a renaissance, as evidenced by the numerous reports in the last 5 years that have relied on such intermediates to undergo unique transformations or generate novel fragments. Since their discovery, these species have been demonstrated to participate in a wide range of reactions with carbon and heteroatom electrophiles, as well as metal complexes, to facilitate the rapid diversification of (aza)bicyclo[1.1.0]butane-containing compounds. Key to this is the relative acidity of the bridgehead C-H bonds which promotes facile deprotonation and subsequent functionalization of an unsubstituted position on the carbon framework via the intermediacy of a metalated (aza)bicyclo[1.1.0]butane. Additionally, the late-stage incorporation of deuterium atoms in strained fragments has led to the elucidation of numerous reaction mechanisms that involve strained bicycles. The continued investigation into the inimitable reactivity of metalated bicycles will cement their importance within the field of organometallic…

Abstract Gain of aromaticity or relief of antiaromaticity along a reaction path are important factors to consider in mechanism studies. Analysis of such changes along potential energy surfaces has historically focused on reactions in the electronic ground state (S 0 ), but can also be used for excited states. In the lowest ππ* states, the electron counts for aromaticity and antiaromaticity follow Baird's rule where 4 n π‐electrons indicate aromaticity and 4 n +2 π‐electrons antiaromaticity. Yet, there are also cases where Hückel's rule plays a role in the excited state. The electron count reversals of Baird's rule compared to Hückel's rule explain many altered physicochemical properties upon excitation of (hetero)annulene derivatives. Here we illustrate how the gain of excited‐state aromaticity (ESA) and relief of excited‐state antiaromaticity (ESAA) have an impact on photoreactivity and photostability. Emphasis is placed on recent findings supported by the results of quantum chemical calculations, and photoreactions in a wide variety of areas are covered.

Abstract Circularly polarized luminescence (CPL) has attracted much interest due to its potential applications on chiral photonic techniques and optoelectronic materials science. As known, dissymmetry factor ( g em ) of CPL is one essential factor for evaluating the features of CPL‐active materials. Much attention has focused on how to increase the g em value, which is one of the most important issues for CPL practical applications. Recently, more and more works have demonstrated that chiral supramolecular could provide the significant strategy to improve the g em value through the orderly helical superstructure of chiral building blocks. Normally, this kind of chiral supramolecular assembly process can be accompanied by chirality transfer and induction mechanism, which can promote the amplification effect on the induced CPL of achiral dyes. In this review, we fully summarized recent advances on the induced CPL‐active materials of chiral supramolecular co‐assemblies, their applications in circularly polarized organic light‐emitting diodes (CP‐OLEDs) and current challenges.

Bioorthogonal chemistry involves selective biocompatible reactions between functional groups that are not normally present in biology. It has been used to probe biomolecules in living systems, and has advanced biomedical strategies such as diagnostics and therapeutics. In this review, the challenges and opportunities encountered when translating in vitro bioorthogonal approaches to in vivo settings are presented, with a focus on methods to deliver the bioorthogonal reaction components. These methods include metabolic bioengineering, active targeting, passive targeting, and simultaneously used strategies. The suitability of bioorthogonal ligation reactions and bond cleavage reactions for in vivo applications is critically appraised, and practical considerations such as the optimum scheduling regimen in pretargeting approaches are discussed. Finally, we present our own perspectives for this area and identify what, in our view, are the key challenges that must be overcome to maximise the impact of these approaches.

Abstract Sulfur(VI)‐fluoride exchange linkage as a next generation of click chemistry was introduced by Sharpless and coworkers in 2014. Distinguished from CuAAC, the SuFEx reaction proceeds under metal‐free conditions, and the reactive linkers are variable, enabling access to a diverse class of linkage compounds. Therein, a series of SuFEx linkers emerged has been widely prevalent in diverse fields. The S VI −F bond in comparison to S VI −Cl bond features excellent stability and chemoselectivity. The linkage chemistry primarily involves the formation of S−O and S−N bonds via commercially available phenols and amines, yet less study on C ‐SuFEx linkage. This review will focus on three types of linkage for SuFEx linkers comprising S−O, S−N, and S−C bonds, and we hope to provide a practical guidance for SuFEx linkage chemistry.

Recently, it has become imperative to develop high energy density as well as high safety lithium-ion batteries (LIBS) to meet the growing energy demand. Among the anode materials used in LIBs, the currently used commercial graphite has low capacity and is a safety hazard due to the formation of lithium dendrites during the reaction. Among the transition metal oxide (TMO) anode materials, TMO based on the intercalation reaction mechanism has a more stable structure and is less prone to volume expansion than TMO based on the conversion reaction mechanism, especially the niobium-based oxide in it has attracted much attention. Niobium-based oxides have a high operating potential to inhibit the formation of lithium dendrites and lithium deposits to ensure safety, and have stable and fast lithium ion transport channels with excellent multiplicative performance. This review summarizes the recent developments of niobium-based oxides as anode materials for lithium-ion batteries, discusses the special structure and electrochemical reaction mechanism of the materials, the synthesis methods and…

Chalcogen bonding (ChB) is the non-covalent interaction occurring between chalcogen atoms as Lewis acid sites and atoms or groups of atoms able to behave as Lewis bases through their lone pair or π electrons. Analogously to its sister halogen bonding, the high directionality of this interaction was implemented for precise structural organizations in the solid state and in solution. Regarding catalysis, ChB is now accepted as a new mode of activation as demonstrated by the increased number of examples in the last five years. In the family of ChB catalysts, those based on tellurium rapidly appeared to overcome their lighter sulfur and selenium counterparts. In this review, we highlight the Lewis acid properties of tellurium-based derivatives in solution and summarize the start-of-the-art of their applications in catalysis.

The separation of actinides from lanthanides in spent nuclear fuel reprocessing is a vital step of nuclear fuel cycle process. As one class of mature industrial extractants, the organophosphorus extractants have been widely used for the extraction and separation of actinides and lanthanides in spent fuel reprocessing due to their strong extraction ability and low-cost acquisition. In this concept, the application scope of tributyl phosphate (TBP), bis(2-ethylhexyl) phosphate (HDEHP), octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO), trialkyl phosphine oxide (TRPO), and purified Cyanex 301 (bis(2,4,4-trimethylpentyl) dithiophosphinic acid, HA301) are introduced, and their extraction mechanism, as well as structure-function relationships for separation of actinides over lanthanides are also discussed. Furthermore, the design criteria, extraction properties and mechanism of several typical newly developed organophosphorus extractants (CMPO-modified calixarene/pillarene, phenanthroline-derived organophosphorus extractants, and phosphate-modified carborane) based on…

Invited for the cover of this issue are Zhao Chen at Jiangxi Science and Technology Normal University and Yue Sun at Tiangong University. For this cover picture, yellow ball containing character "D" represents donor, green ball containing character "A" represents acceptor. The image depicts eight donor-donor-acceptor-type carbazole derivatives that display full-color emission, and a luminogen that shows red to near-infrared mechano-fluorochromism and a photodynamic therapy effect. Read the full text of the article at 10.1002/chem.202203797.

Carbon dots (CDs) smaller than 10 nm constitute a new type of fluorescent carbon-based nanomaterial. They have attracted much attention owing to their unique structures and excellent photoelectric properties. Primitive CDs usually comprise carbon and oxygen and are synthesized in one step from various natural products or synthetic organic compounds, usually via microwave or hydrothermal methods. However, the uniformity of surface functional groups often make CDs lack the diversity of active sites required for specific applications. Therefore, the functionalization of CDs by specific groups is a powerful strategy for improving their photophysical and photochemical properties. This paper reviews surface modification strategies to overcome these shortcomings. Functionalizing CDs using covalent or non-covalent modification can give them unique properties and broaden their applicability.

Covalent organic frameworks (COFs) are a type of crystalline porous polymer composed of light elements through strong covalent bonds. COFs have attracted considerable attention due to their unique designable structures and excellent material properties. Currently, COFs have shown outstanding potential in various fields, including gas storage, pollutant removal, catalysis, adsorption, optoelectronics, and their research in the sensing field is also increasingly flourishing. In this review, we focus on COF-based sensors. Firstly, we elucidate the fundamental principles of COF-based sensors. Then, we present the primary application areas of COF-based sensors and their recent advancements, encompassing gas, ions, organic compounds, and biomolecules sensing. Finally, we discuss the future trends and challenges faced by COF-based sensors, outlining their promising prospects in the field of sensing.

Liquid crystal elastomers (LCEs) are active soft matter-based materials with strong stimulus responsiveness and reversible, large-shape morphing capabilities. LCEs have demonstrated broad and growing applications in soft robotics, wearable devices, artificial muscles, and optical machines. The actuation intelligence and advanced functionality of LCEs depend on the smartness and properties of structures. In this review, we discuss recent advances in structure-induced intelligence of LCEs, specifically the integration of structural properties with the alignment and processing of LCEs. The structural design principles for three categories consisting of common structures (film, fiber, and tubule), smart structures (origami, kirigami, mechanical metamaterial, topology, and topography), and complex structures (monolithic and integrated) are presented. Various alignment controls of LCEs, including mechanical, surface, field-assisted, and shear alignment, are capable of inducing structural properties. The coupling and collaboration mechanisms of the LCE structures and the generated…

The regio-, site-, stereo- or chemoselective homogeneous catalytic transformations are extremely important for the growth/success of the current chemical industry. Based on empirical, theoretical or intuitive knowledge, several synthetic strategies, such as ligand design, transient directing group, metal node alternation, metal-ligand cooperation, pore decoration, biomimetic, have already been developed for the selective functionalization of organic substrates. In comparison to the other tactics, the use of noncovalent interactions for the control of selectivity in catalytic transformations of organic compounds may avoid multi-steps, reduce time of synthetic procedure, decrease cost of operation, and increase reactivity of catalyst. In fact, enzymes achieve a high selectivity through noncovalent interactions in biochemical processes in Nature. Guided by the impressive performance of enzymes in biosynthesis and biodegradation reactions, various types of synthetic metal complex or organocatalysts have already been developed, in which the catalyst-substrate noncovalent interactions…

With the increasing demand for low-cost and high-safety portable batteries, aqueous zinc-ion batteries (ZIBs) have been regarded as a potential alternative to the lithium-ion batteries, bringing about extensive research dedicated in the exploration of high-performance and highly reversible ZIBs. Although separators are generally considered as non-active components in conventional research on ZIBs, advanced separators designs seem to offer effective solutions to the majority of issues within ZIBs system. These issues encompass concerns related to the zinc anode, cathode, and electrolyte. Initially, we delve into the origins and implications of various inherent problems within the ZIBs system. Subsequently, we present the latest research advancements in addressing these challenges through separators engineering. This includes a comprehensive, detailed exploration of various strategies, coupled with instances of advanced characterizations to provide a more profound insight into the mechanisms that influence the separators. Finally, we undertake a multi-criteria evaluation, based on…

Eukaryotic transcription factors (TFs) are the final integrators of a complex molecular feedback mechanism that interfaces with the genome, consolidating information for transcriptional regulation. TFs consist of both structured DNA-binding domains and long intrinsically disordered regions (IDRs) embedded with motifs linked to transcriptional control. It is now well established that the dynamic multifunctionality of IDRs is the basis for a wide spectrum of TF functions necessary to navigate and regulate the human genome. This review dissects the chemical features of TF IDRs that endow them with structural plasticity that is central to their functions in the nucleus. Sequence analysis of a set of over 1600 human TFs through AlphaFold was used to identify key features of their IDRs. Recent studies were then highlighted to illustrate IDR involvement in processes such as protein interactions, DNA binding and specificity, chromatin opening, and phase separation. To expand our understanding of TF functions, future directions are suggested for integrating experiments and simulations, from…

Skeletal editing via single-atom insertion reactions involving nitrogen heterocycles have been reported by two innovative and complementary methods for the conversion of pyrroles and indoles to pyridines, quinolines and quinazolines. The use of electrophilic carbonyl cation equivalents and in situ generated nitrenes enables molecular editing to transform heterocycles forming the foundation of best-selling pharmaceuticals. Considering the importance of heterocycles in medicinal chemistry, biology and natural products, these methods offer innovative approach to complex molecular structures by heterocycle diversification and peripheral editing.

Coinage metal (gold, silver, and copper) complexes are attractive candidates to substitute the widely studied noble metal complexes, such as, iridium(III) and platinum(II), as luminescent materials in organic light-emitting diodes (OLEDs). However, the development of coinage metal complexes exhibiting high emission quantum yields and short exciton lifetimes is still a formidable challenge. In the past few years, coinage metal complexes featuring a carbene-metal-amide (CMA) motif have emerged as a new class of luminescent materials in OLEDs. Thanks to the coinage metal-bridged linear geometry, coplanar conformation, and the formation of excited states with dominant ligand-to-ligand charge transfer character and reduced metal d-orbital participation, most CMA complexes have high radiative rates via thermally activated delayed fluorescence. Currently, the family of CMA complexes have rapidly evolved and remarkable progresses in CMA-based OLEDs have been made. Here, a Concept article on CMA complexes is presented, with a focus on molecular design principles, the correlation between…

Abstract The synthesis and characterisation of two series of low molar mass mesogens, the (4‐nitrophenyl) 2‐alkoxy‐4‐(4‐methoxybenzoyl)oxybenzoates (NT3. m ) and the (3‐fluoro‐4‐nitrophenyl) 2‐alkoxy‐4‐(4‐methoxybenzoyl)oxybenzoates (NT3F. m ), are reported in order to investigate the effect of changing the position of a lateral alkoxy chain from the methoxy‐substituted terminal ring to the central phenyl ring in these two series of materials based on RM734. All members of the NT3. m series exhibited a conventional nematic phase, N, which preceded the ferroelectric nematic phase, N F , whereas all the members of the NT3F. m series exhibited direct N F ‐I transitions except for NT3F.1 which also exhibited an N phase. These materials cannot be described as wedge‐shaped, yet their values of the ferroelectric nematic‐nematic transition temperature, T , exceed those of the corresponding materials with the lateral alkoxy chain located on the methoxy‐substituted terminal ring. In part, this may be attributed to the effect that changing the position of the lateral alkoxy chain has on the…

Abstract Here we describe the development of a sustainable and cost‐effective approach for catalytic cross‐coupling reactions in mechanochemistry. It is found that the substrate‘s impact with the vessel wall alone is sufficient to initiate the reaction, thus indicating that milling balls function primarily as a mixing agent for direct mechanocatalytic Suzuki coupling. The absence of milling balls can be offset by adjusting the rheology using liquid‐assisted grinding (LAG). The LAG sweet spot of 0.25 μL mg −1 is confirmed for both resonance acoustic mixers (RAMs) and ball‐free mixer mills, and is higher than in the presence of milling balls. RAMs exhibit excellent performance in the Suzuki reaction, achieving yields of 90 % after 60 min and complete conversion after 90 min. The longevity of the milling vessel is significantly improved in a RAM, allowing for at least 20 reactions without deterioration.

Abstract The activation and functionalization of carbon dioxide entails great interest related to its abundance, low toxicity and associated environmental problems. However, the inertness of CO2 has posed a challenge towards its efficient conversion to added‐value products. In this review we discuss one of the strategies that have been widely used to capture and activate carbon dioxide, namely the use of donor‐acceptor interactions by partnering a Lewis acidic and a Lewis basic fragment. This type of CO2 activation resembles that found in metalloenzymes, whose outstanding performance in catalytically transforming carbon dioxide encourages further bioinspired research. We have divided this review into three general sections based on the nature of the active sites: metal‐free examples (mainly formed by frustrated Lewis pairs), main group‐transition metal combinations, and transition metal heterobimetallic complexes. Overall, we discuss one hundred compounds that cooperatively activate carbon dioxide by donor‐acceptor interactions, revealing a wide range of structural motifs.

Indigo, one of the most ancient and abundant dyes in human history, has recently emerged as a potential functional motif due to its intriguing photochemical properties. This review aims to provide insights into both the preparation of these molecules and their utilization in molecular systems. First, the synthesis of the indigo core as well as available methods to derivatize indigo are described to outline synthetic strategies to build the desired molecular structures. Then, the photochemical behavior of indigos is discussed, with particular focus on E-Z photoisomerization and photoinduced electron transfer. Connections between the molecular structures and their photochemical properties are highlighted and serve as guiding principles for designing indigos to be applied as photoresponsive tools.

Abstract Plastics are indispensable materials in modern society; however, their extensive use has contributed to the depletion of finite natural resources and caused severe environmental issues. One end‐of‐use solution for plastics involves the chemical recycling of polymers back to monomers for repolymerization to virgin polymers without changing the material properties, allowing the establishment of a circular material economy. This concept focuses on the critical advantages of chemically recyclable polymers in terms of monomer design, material properties, and the feasibility of bulk depolymerization. The recyclability via bulk thermolysis of various polyesters, CO2‐based polycarbonates, and polyacetals produced via ring‐opening polymerization is highlighted through discussions regarding rational monomer design and efficient catalyst development. An outlook and perspective are provided to delineate the future challenges in the rational design of monomer and polymer structures that deliver the desired materials performance while being suitable for bulk thermolysis with high…

Alkaline hydrogen-electricity energy conversion technologies, involving anion exchange membrane fuel cells (AEMFCs) and anion exchange membrane water electrolyzers (AEMWEs) are more appealing than the acidic counterparts due to the elimination of precious metal catalysts. However, the physicochemical properties of anion exchange membrane (AEMs), i.e., ionic conductivity, mechanical strength, stability, etc., are inferior to that of proton exchange membranes (PEMs), thus hindering these alkaline technologies from practical employment. To promote their development, we summarize the main challenges and the corresponding strategies of AEMs for the application of AEMFCs and AEMWEs in this review. The hydroxide transportation mechanism, ion exchange capacity, hydration and microscopic morphology that are relevant to the ionic conductivity are discussed firstly. Following the ionic conductivity, another obstacle, stability of AEMs is comprehensively described in terms of alkaline stability, mechanical stability and electrochemical stability. Upon integrating into the devices, water…

Silanols are valuable and important compounds, which have found widespread applications in the field of materials science, synthetic chemistry, and medicinal chemistry. Although a handful of approaches have been developed for the synthesis of various silanols, access to enantioenriched silicon-stereogenic silanols remains underdeveloped. This Concept article intends to summarize and highlight recent advances in the construction of silicon-stereogenic silanols and endeavors to encourage further research in this area.

Abstract We describe an operationally simple and user‐friendly protocol that allows the site‐selective hydrogenation and deuteration of di‐, tri‐ and tetrasubstituted benzylic olefins by electroreduction while other groups prone to hydrogenation are present. The radical anionic intermediates react with the most inexpensive hydrogen/deuterium source H2O/D2O. Our method overcomes many limitations that arise from previously reported electroreductive hydrogenations. The applicability of this reaction is demonstrated by a broad substrate scope (>50 examples) that focuses on functional group tolerance and sites that are affected by metal‐catalyzed hydrogenation (alkenes, alkynes, protecting groups).

Asymmetric [3+2] cycloaddition reactions are fascinating and powerful methods for the synthesis of enantioenriched pyrrolidines up to four stereocentres. Pyrrolidines are important compounds for both biology and organocatalytic applications. This review summarizes the most recent advances in the enantioselective synthesis of pyrrolidines by [3+2] cycloadditions of azomethine ylides using metal catalysis. It has been organized by the type of metal catalysis used and further arranged by the complexity nature of dipolarophile. The presentation of each reaction type highlights their advantages and limitations.

Abstract Aqueous zinc‐ion batteries (ZIBs) are gaining significant attention for their numerous advantages, including high safety, high energy density, affordability, and environmental friendliness. However, the development of ZIBs has been hampered by the lack of suitable cathode materials that can store Zn2+ with high capacity and reversibility. Currently, vanadium‐based materials with tunnel or layered structures are widely researched owing to their high theoretical capacity and diversified structures. However, their long‐term cycling stability is unsatisfactory because of material dissolution, phase transformation, and restrictive kinetics in aqueous electrolytes, which limits their practical applications. Different from previous reviews on ZIBs, this review specifically addresses the critical issues faced by vanadium‐based cathodes for practical aqueous ZIBs and proposes potential solutions. Focusing on vanadium‐based cathodes, their ion storage mechanisms, the critical parameters affecting their performance, and the progress made in addressing the aforementioned problems are…

Abstract Herein, the electronic structure and bonding character of the stable cyclo[18]carbon (C18) precursor, C18Br6, are thoroughly characterized by molecular orbital (MO), density of states (DOS), bond order (BO), and interaction region indicator (IRI) analyses. The delocalization characters of out‐of‐plane and in‐plane π‐electrons (labeled as πout‐ and πin‐electrons, respectively) in bonding regions were examined using localized orbital locator (LOL) and electron localization function (ELF). The aromaticity was investigated, studying the molecular magnetic response to external magnetic field by computing the magnetically induced current density (Jind), iso‐chemical shielding surface (ICSS), anisotropy of the induced current density (AICD), and the induced magnetic field (Bind). All these analyses indicate that C18Br6 is a globally aromatic species with lower aromaticity than C18, and the blocking of in‐plane π‐conjugation (labeled as πin‐conjugation) by the presence of ‐Br substituents in it is the underlying cause for the weakening of molecular aromaticity.

In contrast to the rapid growth of electrophotocatalysis in recent years, enantioselective catalytic reactions powered by this unique methodology remain rare. In this work, we report an electrophotochemical metal-catalyzed protocol for direct asymmetric decarboxylative cyanation of aliphatic carboxylic acids. The synergistic merging of electrophotochemical cerium catalysis and asymmetric electrochemical copper catalysis permits mild reaction conditions for the formation and utilization of the key carbon centered radicals by combining the power of light and electrical energy. Electrophotochemical cerium catalysis enables radical decarboxylation to produce alkyl radicals, which could be effectively intercepted by asymmetric electrochemical copper catalysis for the construction of C-CN bonds in a highly stereoselective fashion. This environmentally benign method smoothly converts a diverse array of arylacetic acids into the corresponding alkyl nitriles in good yields and enantioselectivities without using chemical oxidants or pre-functionalization of the acid substrates and can be…

Abstract Aqueous zinc‐ion batteries (AZIBs) have attracted considerable attention. However, due to the uneven distribution of charge density at Zn anode‐electrolyte interface, severe dendrites and corrosion are generated during cycling. In this work, a facile and scalable strategy to address the above‐mentioned issues has been proposed through regulating the charge density at Zn anode‐electrolyte interface. As a proof of concept, amidinothiourea (ATU) with abundant lone‐pair electrons is employed as an interfacial charge modifier for Zn anode‐electrolyte interface. The uniform and increased interfacial charge distribution on Zn anode‐electrolyte interface has been obtained. Moreover, the unique Zn‐bond constructed between N atoms and Zn2+ as well as the hydrogen bonds are formed among ATU and Ac− anion/active H2O, which promote the migration and desolvation behavior of Zn2+ at anode‐electrolyte interface. Accordingly, at a trace concentration of 0.01 mg mL−1 ATU, these features endow Zn anode with a long cycling life (more than 800 h), and a high average Columbic efficiency (99.52…

Atropisomers have emerged as important structural scaffolds in natural products, drug design, and asymmetric synthesis. Recently, N-N biaryl atropisomers have drawn increasing interest due to their unique structure and relatively stable axes. However, its asymmetric synthesis remains scarce compared to its well-developed C-C biaryl analogs. In this concept, we summarize the asymmetric synthesis of N-N biaryl atropisomers including N-N pyrrole-pyrrole, N-N pyrrole-indole, N-N indole-indole, and N-N indole-carbazole, during which a series synthetic strategies are highlighted. Also, a synthetic evolution is briefly reviewed and an outlook of N-N biaryl atropisomers synthesis is offered.

Atropisomeric heterobiaryls play a vital role in natural products, chiral ligands, organocatalysts, and other research fields, which have aroused great interest from chemists in recent years. Until now, a growing number of optically active heterobiaryls based on indole, quinoline, isoquinoline, pyridine, pyrrole, azole, and benzofuran skeletons have been successfully synthesized through metal or organic catalytic cross-coupling, functionalization of prochiral or racemic heterobiaryls, and ring formation. Among different strategies for the atroposelective synthesis of heterobiaryls, the strategy of ring formation has become a vital tool toward this goal. In this review, we summarize the enantioselective synthesis of axially chiral heterobiaryls through ring formation approaches, such as cycloaddition, cyclization, and chirality conversion. Meanwhile, the reaction mechanism and the corresponding applications of the chiral heterobiaryls are also discussed.

Abstract Zinc‐based energy storage has lately gained popularity due to natural abundance, operational safety, high energy density. Unfortunately, dendrite growth is a common and intractable issue faced in existing zinc‐ion batteries to shorten cycle lifespan/stability. This review summarizes recent progress in assembly component (e. g., anode, electrolyte, separator) engineering for dendrite‐free zinc‐ion batteries. First, diversiform strategies of Zn surface modification and Zn host design are presented to shield the fundamental adverse effect aroused by uneven zinc deposition on the anode. Then, subtle deployments of electrolyte constituents are illustrated to optimize the Zn2+ solvation structure for ultimate dendrite control and Coulombic efficiency elevation in aqueous systems and beyond (e. g., eutectic electrolytes). Furthermore, rational manipulation of advanced separators and the upgrade of zinc metal‐free Zn2+‐storage devices are briefly discussed to explore the dendrite‐free and high‐level Zn2+‐storage. Finally, challenges and perspectives are proposed to offer research…

Abstract In recent years, the synthesis of C‐aryl glycosides hrough C−H functionalization has attracted extensive attention of organic synthesis chemists due to its steps and atomic economy. In this concept, we systematically summarizes the synthesis of C‐aryl glycosides with diverse regioselectivity and diastereoselectivity from the perspective of C−H arylation of glycosides and C−H glycosylation of arenes. It can be found that a series of recently developed C−H glycosylation reactions have higher site‐selectivity and diastereomeric selectivity than Friedel–Crafts glycosylation reaction. The reaction conditions are milder, which can be compatible with acid‐sensitive protective groups, such as acetals or ketals, and the deprotection is more convenient. It can be seen that there are few reports on remote C−H glycosylation of aromatic hydrocarbons, which is a new field and needs further research. In addition, C−H glycosylation has a lot of shortcomings, which need to be further explored: a) the precise regulation of stereoselectivity in the reaction process also needs further…

Caffeine is a natural compound found in plant seeds that after consumption by humans effects the central nervous system as well as the cardiovascular system. In general, the cytochrome P450 enzymes in the liver are involved in the biodegradation of caffeine, which gives paraxanthine, theobromine and theophylline products. There has been debate for many years why multiple products are obtained and how their distributions are determined. To this end we performed a high-level computational study using a combination of molecular dynamics and quantum mechanical approaches. A series of quantum chemical cluster models on the mechanism of caffeine activation by P450 model complexes give hydrogen atom abstraction barriers that predicts the correct ordering and statistical distribution of products. Our studies highlight that second-coordination sphere effects and thermochemical properties of the substrate determine the product distributions.

Thioamides are naturally occurring isosteres of amide bonds in which the chalcogen atom of the carbonyl is changed from oxygen to sulfur. This substitution gives rise to altered nucleophilicity and hydrogen bonding properties with importance for both chemical reactivity and non-covalent interactions. As such, thioamides have been introduced into biologically active compounds to achieve improved target affinity and/or stability towards hydrolytic enzymes but have also been applied as probes of protein and peptide folding and dynamics. Recently, a series of new methods have been developed for the synthesis of thioamides as well as their utilization in peptide chemistry. Further, novel strategies for the incorporation of thioamides into proteins have been developed, enabling both structural and functional studies to be performed. In this Review, we highlight the recent developments in the preparation of thioamides and their applications for peptide modification and study of protein function.

New developments in the field of Lewis acidity are highlighted, with the focus of novel Lewis acids and Lewis superacids of group 2, 13, 14, and 15 elements. Several important basics, illustrated by modern examples (classification of Donor-Acceptor (DA) complexes, amphoteric nature of any compound in terms of DA interactions, reorganization energies of main group Lewis acids and the role of the energies of frontier orbitals) are presented and discussed. It is emphasized that the Lewis acidity phenomena are general and play vital role in different areas of chemistry: from weak "atomophilic" interactions to the complexes of Lewis superacids.

Abstract The industrial ammonia synthesis process consumes a lot of energy and causes serious environmental pollution. As a sustainable approach for ammonia synthesis, photocatalytic nitrogen reduction employing water as the reducing agent has a lot of potential. A simple surfactant‐assisted solvothermal method is used to synthesize g‐C 3 N 4 nanotubes with flower‐like spherical BiOBr grown inside and outside (BiOBr/g‐C 3 N 4 , BC). The hollow tubular structure realizes the full use of visible light by the multi‐scattering effect of light. Large surface areas and more active sites for N 2 adsorption and activation are present in the distinctive spatially dispersed hierarchical structures. Particularly, the quick separation and transfer of electrons and holes are facilitated by the sandwich tubular heterojunctions and tight contact interface of BiOBr and g‐C 3 N 4 . The maximal NH 3 generation rate of the BiOBr/g‐C 3 N 4 composite catalysts can reach 255.04 μmol⋅ g −1 ⋅ h −1 , and it is 13.9 and 5.8 times that of pure BiOBr and g‐C 3 N 4 . This work provides a novel method for…

Abstract The reaction of the Ru(PPh3)3Cl2 with HL1−3−OH (−OH stands for the oxime hydroxyl group; HL1−OH=diacetylmonoxime‐S‐benzyldithiocarbazonate; HL2−OH=diacetylmonoxime‐S‐(4‐methyl)benzyldithiocarbazonate; and HL3−OH=diacetylmonoxime‐S‐(4‐chloro)benzyl‐dithiocarbazonate) gives three new ruthenium complexes [RuII(L1−3−H)(PPh3)2Cl] (1–3) (−H stands for imine hydrogen) coordinated with dithiocarbazate imine as the final products. All ruthenium(II) complexes (1–3) have been characterized by elemental (CHNS) analyses, IR, UV‐vis, NMR (1H, 13C, and 31P) spectroscopy, HR‐ESI‐MS spectrometry and also, the structure of 1–2 was further confirmed by single crystal X‐ray crystallography. The solution/aqueous stability, hydrophobicity, DNA interactions, and cell viability studies of 1–3 against HeLa, HT‐29, and NIH‐3T3 cell lines were performed. Cell viability results suggested 3 being the most cytotoxic of the series with IC50 6.9±0.2 μM against HeLa cells. Further, an apoptotic mechanism of cell death was confirmed by cell cycle analysis and Annexin V‐FITC/PI double staining techniques. In…

Abstract Electrophilic double bond functionalization – intramolecular enolate alkylation sequence was used to obtain a series of bridged and fused bicyclo[m.n.k]alkane derivatives (i. e., bicyclo[4.1.1]octanes, bicyclo[2.2.1]heptanes, bicyclo[3.2.1]octanes, bicyclo[3.1.0]hexanes, and bicyclo[4.2.0]heptanes). The scope and limitations of the method were established, and applicability to the multigram synthesis of target bicyclic compounds was illustrated. Using the developed protocols, over 50 mono‐ and bifunctional building blocks relevant to medicinal chemistry were prepared. The synthesized compounds are promising isosteres of benzene and cycloalkane rings, which is confirmed by their physicochemical and structural characterization (p K a , Log P , and exit vector parameters (EVP)). “Rules of thumb” for the upcoming isosteric replacement studies were proposed.

Exploiting effective non-noble metal electrocatalysts for oxygen reduction reaction (ORR) is crucial for fuel cells and metal-air batteries. Herein, we designed and fabricated Co nanoparticles confined in Mo/N co-doped polyhedral carbon frameworks (Co-NP/MNCF) derived from polyoxometalate-encapsuled metal-organic framework, which showed comparable ORR performance with commercial Pt/C and a larger diffusion-limited current density. Moreover, the Co-NP/MNCF also exhibited excellent ORR stability and methanol tolerance. These appealing performances can be attributed to the porosity regulation and heteroatom doping of metal-organic framework derived polyhedral carbon frameworks, which could be beneficial for the exposure of more active sites, the optimization of electronic structure and the mass transfer of electrolyte/electron/ion.

Abstract Strained compounds constitute a highly topical area of research in chemistry. Borirene and borirane both feature a BC 2 three‐membered ring. They can be viewed as the structural analogues of cyclopropane and cyclopropene, where a CH 2 unit of the carbonaceous counterparts is replaced with BH, respectively. Indeed, this structural variation introduces numerous intriguing aspects. For instance, borirane and borirene are both Lewis acidic due to the presence of a tricoordinate borane center. In addition, borirene is 2π aromatic according to Hückel's rule. In addition to their ability to form adducts with Lewis bases and the capacity of borirenes to act as ligands in coordination with metals, both borirenes and boriranes exhibit ring‐opening reactivity due to the considerable ring strain. Under specific conditions, coordinated boriranes can even cleave two BC bonds to serve as formal borylene sources (although the reaction mechanisms are quite complex). On the other hand, recent successful syntheses of benzoborienes and their carborane‐based three‐dimensional analogues (also…

The field of anion supramolecular chemistry has received more and more attention in recent years. Anions with diverse types and geometries have been widely used for the synthesis of ionic spin crossover (SCO) complexes. This review is devoted to anion effects on the molecular, supramolecular structures and magnetic properties of discrete SCO compounds. Firstly, typical anions used in the synthesis of these compounds are briefly summarized according to their various geometries. This is followed by a collection of representative examples of anion-based SCO compounds, whose SCO properties are analyzed in terms of supramolecular interactions, geometry and charge of anions. In the third part, anion effects on SCO complexes of different kinds of metal centers and ligands are outlined and finally remarks on the synthesis new type of ionic SCO complexes in the future are described.

Abstract The alkaline‐earth metals Mg and Ca are too inert for the direct metalation of primary and secondary amines. Consequently, activation prior to use is required. Alternatively, the Grignard reagents RMgX (R=alkyl, aryl, X=halide) can be applied in metalation of amines. However, such a straightforward procedure for the synthesis of alkylcalcium reagents is disadvantageous due to diverse side reactions, including Wurtz‐type C−C coupling and ether degradation reactions. Therefore, suspensions of magnesium or calcium with amine can be treated in a smooth reaction with ethyl bromide in an ethereal solvent at room temperature. Intermediately formed RAeX (Ae=alkaline‐earth metal, i. e., Mg, Ca) either metalates amines yielding the corresponding amides in an in situ Grignard metalation method (iGMM) or adds across C=N bonds of imines in an in situ Grignard addition method (iGAM). The amides R’2N‐AeX (Ae=Mg: Hauser bases) undergo Schlenk‐type ligand exchange reactions yielding homoleptic Ae(NR’2)2 and potentially sparingly soluble AeX2.

Carbon dots (CDs) are an emerging class of carbon nanoparticles, which for their characteristics have found applications in many fields such as catalysis, materials and biomedicine. Within this context, the application of CDs as antibacterial agents has received much attention in very recent years, while their use as antifungal nanoparticles has been scarcely investigated. Here we report a systematic investigation of the surface functional groups of CDs to study their influence on these nanoparticles' against Candida albicans. Three classes of CDs have been synthesised and fully characterized. A thorough in vitro and in vivo biological screening against C. albicans was performed to test their antifungal, antiadhesion and antibiofilm formation activities. Moreover, the interaction with C. albicans cells was investigated by microscopic analysis. Our results evidence how the presence of a positively polarised surface results crucial for the internalization into COS-7 cells. Positively charged nanoparticles were also able to inhibit adhesion and biofilm formation, to interact with the…

Abstract Lithium‐sulfur batteries demonstrate enormous energy density are promising forms of energy storage. Unfortunately, the slow redox kinetics and polysulfides shuttle effect are some of the factors that prevent the its development. To address these issues, the hybrid membrane with combination of nickel diselenide nanosheets modified carbon nanotubes (NSN@CNTs) and utilized Li2S6 catholyte for lithium sulfur battery. The conductive CNTs facilitates fast electronic/ionic transport, while the polarity of NSN as a strong affinity to lithium polysulfides, effectively anchoring them, facilitating the redox conversion of polysulfide species, and effectively diminishing reaction barriers. The cell with NSN@CNTs delivers the first discharge capacity of 1123.8 mAh g−1 and maintains 786.5 mAh g−1 after 300 cycles (0.2 C) at the sulfur loading 5.4 mg. Its rate capability is commendable, enabling it to sustain a capacity of 559.8 mAh g−1 even at a high discharge rate of 2 C. In addition, its initial discharge capacity can remain 8.33 mAh even at 10.8 mg for duration of 100 cycles. This…

Abstract The dearomatization reaction is a powerful method for transformation of simple aromatic compounds to unique chemical architectures rapidly in synthetic chemistry. Over the past decades, the chemistry in this field has evolved significantly and various important organic compounds such as crucial bioactive molecules have been synthesized through dearomatization. In general, photochemical conditions or assistance by transition metals are required for dearomatization of rigid arenes. Recently, main‐group elements, especially naturally abundant elements in the Earth's crust, have attracted attention as they have low toxicity and are cost‐effective compared to the late transition metals. In recent decades, a variety of low‐valent main‐group molecules, which enable the activation of stable aromatic compounds under mild conditions, have been developed. This minireview highlights the developments in the chemistry of dearomatization of C 6 aromatic hydrocarbons by main‐group compounds leading to the formation of seven‐membered EC 6 (E=main‐group elements) ring or cycloaddition…

Asymmetric catalysis has long been recognized as a powerful tool for the synthesis of enantioenriched molecules. In addition to precise enantiocontrol, high-atom economy, which is crucial for practicality, has always been pursued by chemists in the development of methodologies. Consequently, deracemization, the direct conversion of a racemic compound to one of its enantiomers, and thus characterized by a 100 % atom efficiency, has attracted increasing interest. Recently, visible-light-driven photocatalysis has been demonstrated to be a promising platform for the development of deracemization. Central to its success is its ability to efficiently overcome the prevailing kinetic issues in chemical transformations and the intrinsic thermodynamic challenges, which typically require the use of additional stoichiometric reagents, thus undermining the original advantages. In this review, the advances in this attractive area are systematically summarized and discussed, with examples organized according to the different modalities of energy transfer and single-electron transfer in…

Podophyllotoxin is an aryltetralin lignan lactone derived from different plants of Podophyllum. It consists of five rings with four chiral centers, one trans-lactone and one aryl tetrahydronaphthalene skeleton with multiple modification sites. Moreover, podophyllotoxin and its derivatives showed lots of bioactivities, including anticancer, anti-inflammatory, antiviral, and insecticidal properties. The demand for podophyllotoxin and its derivatives is rising as a result of their high efficacy. As a continuation of our previous review (Chem. Eur. J., 2017, 23, 4467-4526), herein, total synthesis, biotransformation, structural modifications, bioactivities, and structure-activity relationships of podophyllotoxin and its derivatives from 2017 to 2022 are summarized. Meanwhile, a piece of update information on the origin of new podophyllotoxin analogues from plants from 2014 to 2022 was compiled. We hope that this review will provide a reference for future high value-added applications of podophyllotoxin and its analogues in the pharmaceutical and agricultural fields.

Abstract Achieving a planar hypercoordinate arrangement of s‐block metals through covalent bonding with ligands is challenging due to the strong ionicity involved. Herein, we report the first case of a neutral binary global minimum containing a planar hexacoordinate beryllium atom. The central Be atom is coordinated by six active Be atoms, the latter in turn are enclosed by an equal number of more electronegative chlorine atoms in the periphery, forming a star‐like phBe cluster (Be©Be 6 Cl 6 ). Importantly, the cluster exhibits dynamically stabilized stemming geometrically from the appropriate matching of metal‐ligand size and electronically from adherence to the octet rule as well as possessing a 6σ/2π double aromaticity. Remarkably, energy decomposition analysis‐natural orbitals for chemical valence (EDA‐NOCV) analysis reveals a significant covalent interaction between the ligand and the central metal beryllium atoms, a fact further supported by a large Wiberg bond index. This cluster is a promising synthetic as its excellent electronic, dynamic and thermodynamic stability.

In recent years, the strategy of merging visible light photocatalysis and organocatalysis has been utilized and applied in a wide range of reactions. Taking advantage of synergistic visible light photocatalysis with organocatalysis, remarkable progress has recently been achieved in modern chemical synthesis. In these dual catalytic systems, photocatalysts or photosensitizers absorb visible light to induce their photo-excited states which can activate unreactive substrates via electron or energy transfer mechanisms, and organocatalysts are usually employed to control the chemical reactivities of the other substrates. This review mainly focuses on the recent development of cooperative catalysis by the combination of organocatalysis and photocatalysis in recent organic synthesis.

Abstract Three synthesis procedures for the covalent‐organic framework (COF) TpPa‐1 are studied with the purpose of setting up the most promising one in a fast and green way, leading to a more environmentally friendly and sustainable process. With conventional heating, good crystallinity and a high BET specific surface area (SSA) of up to 1007 m 2 ⋅ g −1 are achieved at 170 °C for 3 days using water as the quintessential green solvent. However, the application of microwave radiation in the synthesis for this crystalline porous polymer allows reaction times to be shortened to 30 min while maintaining structural and textural properties (BET SSA of 928 m 2 ⋅ g −1 ) and obtaining yields close to 98 % (vs. 90 % in the hydrothermal synthesis). The water‐assisted mechanochemical synthesis is also an environmentally friendly synthetic approach; with heating at 170 °C in a two‐step process (10+10 min), high crystallinity is achieved, a BET SSA of 960 m 2 ⋅ g −1 and a yield of 98 % for TpPa‐1.

Dual-state emission luminogens (DSEgens) are receiving research interest in the construction of multifunctional materials due to their inherent advantage of high emission efficiency in both the molecularly dispersed solution state and the solid state. However, it remains challenging in synthesizing DSEgens via a delicate manipulation of the molecular structures. This work presents an example of bright DSEgen synthesis by tuning the molecular electronic structures and conformations. Three coumarin-tetraphenylethylene (TPE) molecules with a donor-acceptor electronic structure and highly twisting conformations have been synthesized. While compound resulting from direct conjugation of coumarin with a TPE unit shows aggregation-induced emission, compound with an N,N-diaminoethyl modification on the 7-position of coumarin and compound with a further phenyl linker between coumarin and TPE units feature strong dual-state emission. Benefiting from their strong solid emission and twisting conformations, these fluorophores display reversible mechanofluorochromism. Finally, applications for…

Abstract Bodipy (BDP)‐perylenebisimide (PBI) donor–acceptor dyads/triad were prepared to study the spin–orbit charge‐transfer intersystem crossing (SOCT‐ISC). For BDP‐PBI‐3, in which BDP was attached at the imide position of PBI, higher singlet oxygen quantum yield (ΦΔ=85 %) was observed than the bay‐substituted derivative BDP‐PBI‐1 (ΦΔ=30 %). Femtosecond transient absorption spectra indicate slow Förster resonance energy transfer (FRET; 40.4 ps) and charge separation (CS; 1.55 ns) in BDP‐PBI‐3, while for BDP‐PBI‐1, CS takes 2.8 ps. For triad BDP‐PBI‐2, ultrafast FRET (149 fs) and CS (4.7 ps) process were observed, the subsequent charge recombination (CR) takes 5.8 ns and long‐lived 3PBI* (179.8 μs) state is populated. Nanosecond transient absorption spectra of BDP‐PBI‐3 show that the CR gives upper triplet excited state (3BDP*) and subsequently, via a slow intramolecular triplet energy transfer (14.5 μs), the 3PBI* state is finally populated, indicating that upper triplet state is involved in SOCT‐ISC. Time‐resolved electron paramagnetic resonance spectroscopy revealed that both…

Abstract The overall photocatalytic CO 2 reduction reaction (PCRR), which uses solar energy to convert CO 2 and H 2 O into chemical feedstocks or fuels without sacrificial reagents, plays a momentous role in CO 2 utilization and solar energy conversion. However, significant challenges remain in achieving efficient conversion. Researchers have explored various strategies to realize the overall PCRR efficiently. In this Review, we first explain the criteria for evaluating the overall PCRR and then summarize the following strategies developed over the past decade to promote it: self‐driving material development, Z‐scheme heterojunction construction, cocatalyst loading, heteroatom doping, surface vacancy creation, and carrier‐material matching. Finally, we discuss essential future research directions in the field. Through this comprehensive Review, we aim to provide strategic guidance for the development of efficient overall PCRR systems.

This paper reports a photochemical C-N coupling of abundant, but less reactive aryl chlorides, with structurally diverse primary and secondary amides by Ni-mediated without an external photocatalyst. Under the irradiation of light (390-395 nm) with a soluble organic amine as the base, the reaction allows for the successful transformation of (hetero)aryl chlorides to a wide range of N-aryl amides. More than 60 examples are shown, demonstrating the feasibility and applicability of this protocol in organic synthesis. Mechanic studies indicate that this amidation proceeds via a Ni(I)-Ni(III) catalytic cycle.

Abstract Plasmonic photocatalysis for CO2 reduction is attracting increasing attention due to appealing properties and great potential for real applications. In this review, the fundamentals of plasmonic photocatalysis and the most recent developments regarding its application in driving CO2 reduction are reported. Firstly, we present the review on the mechanism of plasmonic photocatalytic CO2 reduction, the energy transfer of plasmon, and the CO2 reduction process on the catalyst surface. Then, the modulation on the plasmonic nanostructures and also the semiconductor counterpart to regulate CO2 photoreduction is discussed. Next, the influence of the core‐shell structure and the interface between the plasmonic metal and semiconductor on the CO2 photoreduction performance is also outlined. In addition, the latest progress on the emerging direction regarding the plasmonic photocatalysis for methane dry reforming with CO2 is especially emphasized. Finally, a summary on the challenges and prospects of this promising field are provided.

This review comprehensively analyses representative examples of Pd(II)-catalyzed late-stage C-H activation reactions and demonstrates their efficacy in converting C-H bonds at multiple positions within drug (derivative) molecules into diverse functional groups. These transformative reactions hold immense potential in medicinal chemistry, enabling the efficient and selective functionalization of specific sites within drug molecules, thereby enhancing their pharmacological activity and expanding the scope of potential drug candidates. Although notable articles have focused on late-stage C-H functionalization reactions of drug-like molecules using transition-metal catalysts, reviews specifically focusing on late-stage C-H functionalization reactions of drug (derivative) molecules using Pd(II) catalysts are required owing to their prominence as the most widely utilized metal catalysts for C-H activation and their ability to introduce a myriad of functional groups at specific C-H bonds. The utilization of Pd-catalyzed C-H activation methodologies demonstrates impressive success in…

Abstract Two novel nona‐coordinated Eu(III) complexes [Eu(btfa)3(Ph‐TerPyr)] (Eu‐1) and [Eu(NTA)3(Ph‐TerPyr)] (Eu‐2) have been synthesized and characterized. The structure of the complexes was elucidated by density functional theory (DFT) methods. The experimental photophysical properties of the complexes were investigated and complemented with theoretical calculations. Effective energy transfer (ET) pathways for the sensitized red luminescence is discussed. The complexes were tested as emitting layers (EML) in organic light emitting diodes (OLEDs). At the optimum doping concentration of 4 wt.%, the double‐EML OLEDs of Eu‐1 exhibited red electroluminescence (EL) with an EQE of 4.0 % and maximum brightness (B)=1179 cd/m2, maximum current efficiency (ηc)=5.64 cd/A, and maximum power efficiency (ηp)=4.78 lm/W at the current density (J) of 10 mA/cm2. Interestingly, the double‐EML OLEDs of Eu‐2 at the optimum concentration of 3 wt.%, displayed an outstanding EL performance with EQE of 7.32 % and B=838 cd/m2, ηc=10.19 cd/A and ηp=10.33 lm/W at J=10 mA/cm2. The EL performance of this…

Chiral organoselenium compounds have shown an important role as intermediates in many areas, such as drug discovery, organic catalysis, and nanomaterials. A lot of different methods have been developed to synthesize chiral compounds which contain selenium, because they have interesting properties and can be used in real life. Over the last few decades, a lot of progress has been made in synthesizing chiral organoselenium compounds. This work gives an overview of the progress made in creating new ways to synthesize chiral organoselenium compounds by categorizing them into groups based on the reactions they undergo. In addition, the use of chiral organoselenium compounds is also discussed.

Self-assembling features, chiroptical activity, and spin filtering properties are reported for 2,15- and 4,13-disubstituted [6]helicenes decorated in their periphery with 3,4,5-tris(dodecyloxy)-N-(4-ethynylphenyl)benzamide moieties. The weak non-covalent interaction between these units conditions the corresponding circularly polarized luminescence and spin polarization. The self-assembly is overall weak for these [6]helicene derivatives that, despite the formation of H-bonding interactions between the amide groups present in the peripheral moieties, shows very similar chiroptical properties both in the monomeric or aggregated states. This effect could be explained by considering the steric effect that these groups could generate in the growing of the corresponding aggregate formed. Importantly, the self-assembling features also condition chiral induced spin selectivity (CISS effect), with experimental spin polarization (SP) values found between 35-40 % for both systems, as measured by magnetic-conducting atomic force microscopy (AFM) technique.

Electrochemistry offers a sustainable platform for discovering reactions involving single-electron transfer (SET) that generates highly reactive and synthetically versatile radical species. Compared with photochemistry similarly specializing in SET which requires expensive photocatalysts, electrochemistry employs low-cost electricity to drive the electron flow. Paired electrolysis makes use of both half-reactions, thus obviating the need for sacrificial reactions and maximizing the atom and energy economy. In convergent paired electrolysis, anodic oxidation and cathodic reduction occur simultaneously to generate two intermediates, which are then coupled to furnish the product. It represents a distinctive approach to challenging redox-neutral reactions. However, the gap between the two electrodes makes it hard for a reactive intermediate to come across the other coupling partner. This concept article summarizes recent state-of-the-art advances on radical-based convergent paired electrolysis, which adopted different strategies to overcome the difficulty.

Abstract In the field of π‐conjugated nanohoops, the size of the macrocycle has a strong impact on its structural characteristics, which in turn affect its electronic properties. In this work, we report the first experimental investigations linking the size of a nanohoop to its charge transport properties, a key property in organic electronics. We describe the synthesis and study of the first example of a cyclocarbazole possessing five constituting building units, namely [5]‐cyclo‐N‐butyl‐2,7‐carbazole, [5]C‐Bu‐Cbz. By comparison with a shorter analogue, [4]‐cyclo‐N‐butyl‐2,7‐carbazole, [4]C‐Bu‐Cbz, we detail the photophysical, electrochemical, morphological and charge transport properties, highlighting the key role played by the hoop size. In particular, we show that the saturated field effect mobility of [5]C‐Bu‐Cbz is four times higher than that of its smaller analogue [4]C‐Bu‐Cbz (4.22×10−5 vs 1.04×10−5 cm2 V−1 s−1). However, the study of the other organic field‐effect transistor characteristics (threshold voltage VTH and subthreshold slope SS) suggest that a small nanohoop is…

Abstract Short and ultra‐short peptides have been recently envisioned as excellent building blocks for the formulation of hydrogels with appealing properties. Due to its simplicity and capability to gel under physiological conditions, Fmoc‐FF (Nα‐fluorenylmethoxycarbonyl‐diphenylalanine), remains one of the most studied low molecular‐weight hydrogelators. Since its first identification in 2006, a plethora of its analogues were synthetized and investigated for the fabrication of novel supramolecular materials. Here we report a description of the Fmoc‐FF analogues in which the aromatic Fmoc group is replaced with other substituents. These analogues are distinguished into five different classes including derivatives: i) customized with solid phase peptide synthesis protecting groups; ii) containing non‐aromatic groups, iii) containing aromatic groups, iv) derivatized with metal complexes and v) containing stimuli‐responsive groups. The morphological, mechanical, and functional effects caused by this modification on the resulting material are also pointed out.

Bioorthogonal click chemistry has become an indispensable part of the biochemist's toolbox. Despite the wide variety of applications that have been developed in recent years, only a limited number of bioorthogonal click reactions have been discovered so far, most of them based on (substituted) azides. In this work, we present a computational workflow to discover new candidate reactions with promising kinetic and thermodynamic properties for bioorthogonal click applications. Sampling only around 0.05 % of an overall search space of over 10,000,000 dipolar cycloadditions, we develop a machine learning model able to predict DFT-computed activation and reaction energies within ∼2-3 kcal/mol across the entire space. Applying this model to screen the full search space through iterative rounds of learning, we identify a broad pool of candidate reactions with rich structural diversity, which can be used as a starting point or source of inspiration for future experimental development of both azide-based and non-azide-based bioorthogonal click reactions.

We show that mechanochemically driven polymorphic transformations can require extremely long induction periods, which can be tuned from hours to days by changing ball milling energy. The robust design and interpretation of ball milling experiments must account for this unexpected kinetics that arises from energetic phenomena unique to the solid state. Detailed thermal analysis, combined with DFT simulations, indicates that these marked induction periods are associated with processes of mechanical activation. Correspondingly, we show that the pre-activation of reagents can also lead to marked changes in the length of induction periods. Our findings demonstrate a new dimension for exerting control over polymorphic transformations in organic crystals. We expect mechanical activation to have a much broader implication across organic solid-state mechanochemistry.

Instrumental techniques able to identify and structurally characterize the aggregation states in thin films of chiral organic π-conjugated materials, from the first-order supramolecular arrangement up to the microscopic and mesoscopic scale, are very helpful for clarifying structure-property relationships. Chiroptical imaging is currently gaining a central role, for its ability of mapping local supramolecular structures in thin films. The present review gives an overview of electronic circular dichroism imaging (ECDi), circularly polarized luminescence imaging (CPLi), and vibrational circular dichroism imaging (VCDi), with a focus on their applications on thin films of chiral organic dyes as case studies.

Narrowband emitters based on the multiple resonance (MR) effect have shown great promises for applications in high-definition displays. Though most reported MR emitters adopt the boron- and nitrogen-doped triangulene-like skeleton following the design of the DABNA series, MR materials with the nitrogen-only indolocarbazole structures have recently emerged and demonstrated good color tunability from violet to deep red and impressive electroluminescence performances in terms of both efficiency and stability. Herein, we will summarize indolocarbazole-based MR materials in recent reports, with emphasis on their molecular design, synthesis, photophysical and electroluminescence properties as well as some future research directions to unlock the full potential of this fascinating class of materials.

Membrane protein purification by means of detergents is key to isolating membrane-bound therapeutic targets. The role of the detergent structure in this process, however, is not well understood. Detergents are optimized empirically, leading to failed preparations, and thereby raising costs. Here we evaluate the utility of the hydrophilic-lipophilic balance (HLB) concept, which was introduced by Griffin in 1949, for guiding the optimization of the hydrophobic tail in first-generation, dendritic oligoglycerol detergents ([G1] OGDs). Our findings deliver qualitative HLB guidelines for rationalizing the optimization of detergents. Moreover, [G1] OGDs exhibit strongly delipidating properties, regardless of the structure of the hydrophobic tail, which delivers a methodological enabling step for investigating binding strengths of endogenous lipids and their role for membrane protein oligomerization. Our findings will facilitate the analysis of challenging drug targets in the future.

Abstract Catalytic hydrogen peroxide (H2O2) generation from oxygen and water enables a sustainable environment to operate in an effective and green energy‐to‐chemical conversion way, which has attracted increasing interest in the fields of energy production and environment treatment. In light of this, tremendous progresses and developments have been made during the past decades in catalytic H2O2 production for pollutant removal from three perspectives including photocatalysis, electrocatalysis or chemical activation. Herein, we critically review the state‐of‐the‐art developments over various procedures of H2O2 generation and its further application, with the existence of photocatalysts, electrocatalysts, and catalysts, respectively. Benefiting from extensively experimental and theoretical investigations, the performance and stability of H2O2 generation and its utilization can be maneuvered by devising catalytic platform based on numerous catalysts with predominant electronic, chemical and physical properties, which endow the catalysts with efficient electrons transportation,…

Abstract Carbon dioxide electroreduction reaction (CO 2 RR) can take full advantage of sustainable power to reduce the continuously increasing carbon emissions. Recycling CO 2 to produce formic acid or formate is a technologically and economically viable route to accomplish CO 2 cyclic utilization. Developing efficient and cost‐effective electrocatalysts with high selectivity towards formate is prioritized for the industrialized applications of CO 2 RR electrolysis. From the previous explored CO 2 RR catalysts, Sn, Bi and In based materials have drawn increasing attentions due to the high selectivity towards formate. However, there are still confronted with several challenges for the practical applications of these materials. Therefore, a rational design of the catalysts for formate is urgently needed for the target of industrialized applications. Herein, we comprehensively summarized the recent development in the advanced electrocatalysts for the CO 2 RR to formate. Firstly, the reaction mechanism of CO 2 RR is introduced. Then the preparation and design strategies of the highly…

A non-solvated alkyl-substituted Al(I) anion dimer was synthesized by a reduction of haloalumane precursor using a mechanochemical method. The crystallographic and theoretical analysis revealed its structure and electronic properties. Experimental XPS analysis of the Al(I) anions with reference compounds revealed the lower Al 2p binding energy corresponds to the lower oxidation state of Al species. It should be emphasized that the experimentally obtained XPS binding energies were reproduced by delta SCF calculations and were linearly correlated with NPA charges and 2p orbital energies.

In recent years, layered double hydroxides (LDH) nanosheets have garnered substantial attention as intriguing inorganic anionic layered clay materials. These nanosheets have captured the attention of researchers due to their unique physicochemical properties. This review aims to showcase the latest advancements in laboratory research concerning LDH nanosheets, with a specific emphasis on their methods of preparation. This review provides detailed insights into the factors influencing the anionic conductivity of LDH, along with delineating the applications of LDH nanosheets in the realm of energy conversion. Notably, the review highlights the crucial role of LDH nanosheets in the oxygen evolution reaction (OER), a vital process in water splitting and diverse electrochemical applications. The review emphasizes the significant potential of LDH nanosheets in enhancing supercapacitor technology, owing to their high surface area and exceptional charge storage capacity. Additionally, it elucidates the prospective application of LDH nanosheets as anion exchange membranes in anion exchange…

Abstract N‐heterocyclic olefin (NHO) derivatives have an electron‐rich as well as highly polarized carabon‐carbon (C=C) double bond because of the electron‐donating nature of nitrogen and sulphur atoms. While NHOs have been developing as novel organocatalysts and ligands for transition‐metal complexes in various organic compound syntheses, different research groups are currently interested in preparing imidazole and triazolium‐based chiral NHO catalysts. Some of them have been used for enantioselective organic transformations, but were still elusive. N‐heterocyclic olefins, the alkylidene derivatives of N‐heterocyclic carbenes (NHC), have shown promising results as effective promoters for numerous organic syntheses such as asymmetric catalysis, hydroborylation, hydrosilylation, reduction, CO2 sequestration, alkylation, cycloaddition, polymerization and the ring‐opening reaction of aziridine and epoxides, esterification, C−F bond functionalization, amine coupling, trifluoromethyl thiolation, amination etc. NHOs catalysts with suitable structures can serve as a novel class of…

Abstract Light‐activated treatments, such as photodynamic therapy (PDT), provide temporal and spatial control over a specific cytotoxic response by exploiting toxicity differences between irradiated and dark conditions. In this work, a novel strategy for developing near infrared (NIR)‐activatable Ru(II) polypyridyl‐based photosensitizers (PSs) was successfully developed through the incorporation of symmetric heptamethine cyanine dyes in the metal complex via a phenanthrimidazole ligand. Owing to their strong absorption in the NIR region, the PSs could be efficiently photoactivated with highly penetrating NIR light (770 nm), leading to high photocytotoxicities towards several cancer cell lines under both normoxic and hypoxic conditions. Notably, our lead PS (Ru‐Cyn‐1), which accumulated in the mitochondria, exhibited a good photocytotoxic activity under challenging low‐oxygen concentration (2 % O2) upon NIR light irradiation conditions (770 nm), owing to a combination of type I and II PDT mechanisms. The fact that the PS Protoporphyrin IX (PpIX), the metabolite of the clinically…

Abstract Electrochemical CO 2 reduction reaction (CO 2 RR) provides a promising approach for sustainable chemical fuel production of carbon neutrality. Neutral and alkaline electrolytes are predominantly employed in the current electrolysis system, but with striking drawbacks of (bi)carbonate (CO 3 2− /HCO 3 − ) formation and crossover due to the rapid and thermodynamically favourable reaction between hydroxide (OH − ) with CO 2 , resulting in low carbon utilization efficiency and short‐lived catalysis. Very recently, CO 2 RR in acidic media can effectively address the (bi)carbonate issue; however, the competing hydrogen evolution reaction (HER) is more kinetically favourable in acidic electrolytes, which dramatically reduces CO 2 conversion efficiency. Thus, it is a big challenge to effectively suppress HER and accelerate acidic CO 2 RR. In this review, we begin by summarizing the recent progress of acidic CO 2 electrolysis, discussing the key factors limiting the application of acidic electrolytes. We then systematically discuss addressing strategies for acidic CO 2 electrolysis,…

β-Amino sulfones are commonly found structural motifs in biologically active compounds. Herein, we report a direct photocatalyzed amino-sulfonylation reaction of alkenes for the efficicient production of important compounds by simple hydrolysis without the need for additional oxidants and reductants. In this transformation, the sulfonamides worked as bifunctional reagents, simultaneously generating sulfonyl radicals and N-centered radicals which were added to alkene in a highly atom-economical fashion with high regioselectivity and diastereoselectivity. This approach showed high functional group tolerance and compatibility, facilitating the late-stage modification of some bioactive alkenes and sulfonamide molecules, thereby expanding the biologically relevant chemical space. Scaling up this reaction led to an efficient green synthesis of apremilast, one of the best-selling pharmceuticals, demonstrating the synthetic utility of the applied method. Moreover, mechanistic investigations suggest that an energy transfer (EnT) process was in operation.

Abstract To meet the requirements for industrial water splitting to generate hydrogen, it is urgent, but still quite challenging to develop highly active and stable electrocatalysts for large‐current‐density hydrogen evolution reaction (HER). Herein, Ru‐incorporated NiSe2 (Ru‐NiSe2) was designed and synthesized. The introduction of Ru results in the formation of hierarchically structured Ru‐NiSe2 with large electrochemical active surface area, and well‐modified electronic structure. As expected, the as‐fabricated Ru‐NiSe2 displays impressive HER activity in 1.0 M KOH, with a low overpotential of 180.8 mV to reach the current density of 1000 mA cm−2. Ru‐NiSe2 also presents outstanding long‐term stability at high current densities, owing to its high intrinsic chemical stability, and strong catalyst‐support interface. Notably, when performed at a certain current density of 1000 mA cm−2, the overpotential increase after 90 h is only 13 mV. Such excellent HER performance of Ru‐NiSe2 demonstrates its great potential for practical use in industrial water splitting.

Analyses of the Cambridge Structural Database and theoretical calculations (PBE0-D3/def2-TZVP level, atoms-in-molecules, natural bond orbital studies) prove the formation of net attractive noncovalent interactions between group 5 elements and electron-rich atoms (neutral or anionic). These kinds of bonding are markedly different from coordination bonds formed by the same elements and possess the distinctive features of σ-hole interactions. The term erythronium bond is proposed to denote these bonds. X-ray structures of vanadate-dependent bromoperoxidases show that these interactions are present also in biological systems.

The prominent role of gold-N-heterocyclic carbene (NHC) complexes in numerous research areas such as homogeneous (photo)catalysis, medicinal chemistry and materials science has prompted organometallic chemists to design gold-based synthons that permit access to target complexes through simple synthetic steps under mild conditions. In this review, the main gold-NHC synthons employed in organometallic synthesis are discussed. Mechanistic aspects involved in their synthesis and reactivity as well as applications of gold-NHC synthons as efficient pre-catalysts, antitumor agents and/or photo-emissive materials are presented.

Abstract Steroids are highly prevalent structures in small‐molecule therapeutics, with the level of oxidation being key to their biological activity and physicochemical properties. These C(sp3)‐rich tetracycles contain many stereocentres, which are important for creating specific vectors and protein binding orientations. Therefore, the ability to hydroxylate steroids with a high degree of regio‐, chemo‐ and stereoselectivity is essential for researchers working in this field. This review will cover three main methods for the hydroxylation of steroidal C(sp3)−H bonds: biocatalysis, metal‐catalysed C−H hydroxylation and organic oxidants, such as dioxiranes and oxaziridines.

N-protonation for numerous fluorophores is widely known as an efficient switch for the fluorescence turn-on/off in acidic conditions, which has been applied in various scenarios that involve pH monitoring. Yet the universal mechanism for fluorescence regulation through N-protonation is still elusive. Herein, the excited state deactivation processes are systematically investigated for a series of nitrogen-containing fluorescent probes through theoretical approaches. Two types of mechanisms for the complex fluorescent phenomena by N-protonation are concluded: one is through the regulation for the transition to a ππ* twisted intramolecular charge transfer (TICT) state; the other one applies for the case when nonradiative decay pathway is predominant by a dark nπ* state, which is also accompanied by an evident structural twisting and can be regarded as another kind of TICT state. More generally, the formation of the TICT state is closely related to the conjugated π-electrons on the single bond that links the acceptor and donor part of fluorophores, which provides a simple strategy for…

Abstract The steric tuning of a tridentate acridane‐derived NNN pincer ligand allows for the isolation of a strictly T‐shaped phosphine that exhibits ambiphilic reactivity. Well‐defined phosphorus‐centered reactivity towards nucleophiles and electrophiles is reported, contrasting with prior reports on this class of compounds. Reactions towards oxidants are also described. The latter result in the two‐electron oxidation of the phosphorus atom from +III to +V and are accompanied by a strong geometric distortion of the NNN pincer ligand. By contrast, cooperative activation of E−H (HCl, HBcat, HOMe) bonds proceeds with retention of the phosphorus redox state. When using H2O as a substrate, the reaction results in the full disassembly of H2O to its constituent atoms, highlighting the potential of this platform for small molecule activation reactions.

Abstract Herein, we have utilized 2‐(2‐hydroxyphenyl)benzimidazole (HBI) to synthesize 3‐(1H‐benzoimidazol‐2‐yl)‐2‐hydroxy‐5‐methyl‐benzaldehyde (HBIA) followed by three Schiff bases by using –ortho (H2BIo), ‐meta (H3BIdm) and ‐para (H2BIp) substituted amino benzoic acids and studied their photophysical properties. We have successfully derived molecular structures of HBI, HBIA and H3BIdm which reveals that in HBI and HBIA, the phenolic −OH is intramolecularly hydrogen bonded with sp2 N of benzimidazole group whereas in H3BIdm, it is hydrogen bonded with imine C=N of Schiff base moiety, which is responsible for different solid state emission properties of the reported compounds. Extensive experimental and theoretical studies show that for all three Schiff bases, in solution due to activation of C=N isomerization, ESIPT operates through benzimidazole site and displays different emission from the solid state. Furthermore, H2BIo, H3BIdm and H2BIp selectively sense Cu2+ in semi aqueous medium with nano‐molar detection limit and in HuH‐7 cells through the inhibition of ESIPT of process.

Abstract We report the formation of metal‐organic cage‐crosslinked polymer hydrogels. To enable crosslinking of the cages and subsequent network formation, we used homodifunctionalized poly(ethylene glycol) (PEG) chains terminally substituted with bipyridines as ligands for the Pd6L4 corners. The encapsulation of guest molecules into supramolecular self‐assembled metal‐organic cage‐crosslinked hydrogels, as well as ultrasound‐induced disassembly of the cages with release of their cargo, is presented in addition to their characterization by nuclear magnetic resonance (NMR) techniques, rheology, and comprehensive small‐angle X‐ray scattering (SAXS) experiments. The constrained geometries simulating external force (CoGEF) method and barriers using a force‐modified potential energy surface (FMPES) suggest that the cage‐opening mechanism starts with the dissociation of one pyridine ligand at around 0.5 nN. We show the efficient sonochemical activation of the hydrogels HG3–6, increasing the non‐covalent guest‐loading of completely unmodified drugs available for release by a factor of ten…

Abstract Methylenedianiline (MDA) is a secondary, undesired, product of the glycolysis process of polyurethane (PU) scraps due to hydrolysis and pyrolysis side reactions. As an aromatic and carcinogen amine, MDA poses different problems in handling, transporting, and labelling recycled polyols derived from glycolysis, hindering the closure of PU recycling loop. Aiming to provide a solution to this issue, in this work different deaminating agents (DAs) were investigated with the purpose of analyzing their reactivity with MDA. A first part of the study was devoted to the analysis of MDA formation as a function of reaction time and catalyst concentration (potassium acetate) during glycolysis. It was observed that the amount of MDA increases almost linearly with the extent of PU depolymerization and catalyst content. Among the DAs analyzed 2‐ethylhexyl glycidyl ether (2‐EHGE), and acetic anhydride (Ac2O) showed interesting performance, which allowed MDA content to be diminished below the limit for labelling prescription in 30 minutes. PU rigid foams were, therefore, synthesized from the…

Abstract The inherent challenges in using metal‐organic frameworks (MOFs) for photocatalytic CO2 reduction are the combination of wide‐range light harvesting, efficient charge separation and transfer as well as highly exposed catalytic active sites for CO2 activation and reduction. We present here a promising solution to satisfy these requirements together by modulating the crystal facet and surface atomic structure of a porphyrin‐based bismuth‐MOF (Bi‐PMOF). The series of structural and photo‐electronic characterizations together with photocatalytic CO2 reduction experiment collectively establish that the enriched Bi active sites on the (010) surface prefer to promote efficient charge separation and transfer as well as the activation and reduction of CO2. Specifically, the Bi‐PMOFs‐120‐F with enriched surface Bi active sites exhibits optimal photocatalytic CO2 reduction performance to CO (28.61 μmol h−1g−1) and CH4 (8.81 μmol h−1g−1). This work provides new insights to synthesize highly efficient main group p‐block metal Bi‐MOF photocatalysts for CO2 reduction through a…

Abstract A new organic‐inorganic hybrid open‐framework molybdovanadate with mixed‐valences of vanadium (V4+/V5+=4/3) and molybdenum (Mo5+/Mo6+=8/2) cations has been synthesized. The complex possesses the unique V/Mo ratio (7/10), fascinating 8‐C topological network and 1D 4‐MR channels (7.793 Å×6.699 Å). Importantly, its catalytic activities for the selective oxidation of benzyl alcohol to benzaldehyde (oxidant: H2O2, 30 wt %) have been well evaluated. The results indicated that it exhibited improved catalytic activities (conv.: 96.8 %) compared with the catalyst (Cpyr)5PV2Mo5W5O40 [conv.: 88.51 %, Cpyr=(C16H32C5H4N)+)], high recyclability and structural stability. Moreover, the conversions and selectivities (conv.: 82.4–92.5 %; sele.: 91.5–95.7 %) of the substrates containing electron donating groups (−OH, −CH3, −OCH3 and −Cl) were significantly higher than those of the substrate containing electron withdrawing group (−NO2) (conv. 67.4 %; sele.: 80.8 %). This is due to the fact that the −NO2 with a large Hammett substituent constant is not conducive to the generation of transition…

Electrochemiluminescence (ECL) is a rapidly growing discipline with many analytical applications from immunoassays to single-molecule detection. At the forefront of ECL research is materials chemistry, which looks at engineering new materials and compounds exhibiting enhanced ECL efficiencies compared to conventional fluorescent materials. In this review, we summarize recent molecular design strategies that lead to high efficiency ECL. In particular, we feature recent advances in the use of thermally activated delayed fluorescence (TADF) emitters to produce enhanced electrochemiluminescence. We also document how hydrogen bonding, aggregation, and crystallization can each be recruited in the design of materials showing enhanced electrochemiluminescence.

A quadruple N-heterocyclic carbene/cobalt/photoredox/Brønsted base catalysis to realize branch-selective hydroacylation of styrenes with aromatic and aliphatic aldehydes is demonstrated. This protocol allows access to branched ketones from readily available materials in an atom-economical manner. The quadruple catalysis can transfer a formyl hydrogen of aldehydes as a hydrogen radical equivalent onto the terminal carbon of an alkene by controlled electron and proton transfers.

Abstract In the past few years, there has been a significant increase in the development and production of perovskite or perovskite‐like materials that do not contain lead (Pb) for the purpose of constructing solar cells. The development and testing of lead‐free perovskite‐like structures for solar cells is crucial. In this study, we used the solar cell capacitance software (SCAPS) to simulate perovskite solar cells based on methyl ammonium bismuth iodide (MA3Bi2I9). The electron‐transport layer, hole‐transport layer, and absorber layer thickness were optimized using SCAPS. The simulated perovskite solar cells (FTO/TiO2/MA3Bi2I9/spiro‐OMeTAD/Au) performed well with a power conversion efficiency of 14.07 % and a reasonable open circuit voltage of 1.34 V, using the optimized conditions determined by SCAPS. Additionally, we conducted experiments to fabricate perovskite solar cells under controlled humidity, which showed a power conversion efficiency of 1.31 %.

Abstract The first germole‐ligated single‐molecule magnets are reported, with contrasting properties found for the near‐linear sandwich complexes [(η8‐COT)Ln(η5‐CpGe]−, where Ln=Dy (1Dy) or Er (1Er), COT is cyclo‐octatetraenyl and CpGe is [GeC4‐2,5‐(SiMe3)2‐3,4‐Me2]2−. Whereas 1Er has an energy barrier of 120(1) cm−1 in zero applied field and open hysteresis loops up to 10 K, the relaxation in 1Dy is characterized by quantum tunneling within the ground state.

Abstract The first 8‐electron Pd/Ag superatomic alloys with an interstitial hydride [PdHAg19(dtp)12] (dtp=S2P(OiPr)2−) 1 and [PdHAg20(dtp)12]+ 2 are reported. The targeted addition of a single Ag atom to 1 is achieved by the reaction of one equivalent of trifluoroacetic acid, resulting in the formation of 2 in 55 % yield. Further modification of the shell results in the formation of [PdAg21(dtp)12]+ 3 via an internal redox reaction, with the system retaining an 8‐electron superatomic configuration. The interstitial hydride in 1 and 2 contributes its 1s1 electron to the superatomic electron count and occupies a PdAg3 tetrahedron. The distributions of isomers corresponding to different dispositions of the outer capping Ag atoms are investigated by multinuclear VT NMR spectroscopy. The emissive state of 3 has a lifetime of 200 μs (λex=448; λem=842), while 1 and 2 are non‐emissive. The catalytic reduction of 4‐nitrophenol is demonstrated with 1–3 at room temperature.

N-heterocyclic carbene (NHC) monolayers are transforming electrocatalysis and biosensor design via their increased performance and stability. Despite their increasing use in electrochemical systems, the integrity of the NHC monolayer during voltage perturbations remains largely unknown. Herein, we deploy surface-enhanced Raman spectroscopy (SERS) to measure the stability of two model NHCs on gold in ambient conditions as a function of applied potential and under continuous voltammetric interrogation. Our results illustrate that NHC monolayers exhibit electrochemical stability over a wide voltage window (-1 V to 0.5 V vs Ag|AgCl), but they are found to degrade at strongly reducing (< -1 V) or oxidizing (>0.5 V) potentials. We also address NHC monolayer stability under continuous voltammetric interrogation between 0.2 V and -0.5 V, a commonly used voltage window for sensing, showing they are stable for up to 43 hours. However, we additionally find that modifications of the backbone NHC structure can lead to significantly shorter operational lifetimes. While these results highlight the…

A novel organocatalyzed [3+2] cycloaddition reaction of nitroolefins with glycosyl azides as well as organic azides has been developed for successful construction of 1,5-disubstituted triazolyl glycoconjugates. This metal-free and acid-free, regioselective synthetic protocol proceeds in the presence of only Schreiner thiourea organocatalysts, which enable the required activation of nitroolefins through double hydrogen bonding. The straightforward, operationally simple, and regioselectivity of this methodology, complementing to the classical RuAAC catalyzed synthesis of 1,5-disubstituted 1,2,3-triazoles. In the presence of catalytic amount of Schreiner thiourea organocatalyst, organic azides react with a broad array of nitroolefins producing a series of diverse 1,5-disubstituted 1,2,3- triazoles in good yields with excellent regioselectivity.

Abstract Helically folded oligoamides of 8‐amino‐2‐quinolinecarboxylic acid composed of up to 41 units were prepared using optimized manual solid‐phase synthesis (SPS). The high yield and purity of the final products places these SPS protocols among the most efficient known to date. Furthermore, analytical methods allowing for the clear identification and purity assessment of the products were validated, including 1H NMR, a seldom used method for such large molecules. Adaption of the SPS protocols, in particular using in situ acid chloride activation under Appel's conditions, made it possible to efficiently implement SPS on a commercial peptide synthesizer, leading to a dramatic reduction of the laboratory work required to produce long sequences. Automation constitutes a breakthrough for the development of helical aromatic oligoamide foldamers.

Abstract The direct amide bond formation between a carboxylic acid and an amine still constitutes a challenging reaction for both academia and industry. We demonstrate herein that several pairs of amines (halogen bond acceptors) and organohalogen sources may be used for the photochemical amidation reaction under either UVA or sunlight irradiation. Our studies led to the identification of pyridine‐CBr4 as an efficient agent to perform amide synthesis under LED 370 nm irradiation, avoiding super‐stoichiometric quantities. An extended substrate scope was demonstrated, showing that the widely used amino and carboxyl protecting groups are compatible with this photochemical protocol, while a number of industrially interesting products and bioactive compounds were synthesized. Direct infusion‐high resolution mass spectrometry studies suggest an unprecedented type of carboxylic acid activation mode upon irradiation, involving the generation of a symmetric anhydride, an active ester with pyridine N‐oxide and a mixed anhydride with hypobromous acid.

Electrochemical aptamer-based (E-AB) biosensors have demonstrated capabilities in monitoring molecules directly in undiluted complex matrices and in the body with the hopes of addressing personalized medicine challenges. This sensing platform relies on an electrode-bound, redox-reporter-modified aptamer. The electrochemical signal is thought to originate from the aptamer undergoing a binding-induced conformational change capable of moving the redox reporter closer to the electrode surface. While this is the generally accepted mechanism, it is notable that there is limited evidence demonstrating conformational change or distance-dependent change in electron transfer rates in E-AB sensors. In response, we investigate here the signal transduction of the well-studied cocaine-binding aptamer with different analytical methods and found that this sensor relies on a redox-reporter - ligand competition mechanism rather than a ligand-induced structure formation mechanism. Our results show that the covalently bound redox reporter, methylene blue, binds at or near the ligand binding site on the…