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This study presents the exploration of sequence‐defined polyurethanes (PUs) as a new class of heteropolymers capable of precise conformational control. Utilizing molecular dynamics simulations, the folding behavior of polyurethane chains is investigated of varying lengths (11, 20, and 50 monomers) in both vacuum and aqueous environments. The simulations reveal that the heterogeneous chains systematically refold to approach the designed target structures better than non‐designed chains or chains with artificially disrupted hydrogen‐bond networks. The subsequent synthesis of an optimized 11‐mer sequence (P1) is achieved through solid‐phase chemistry, with thorough characterization via NMR, MS, and SEC confirming the accuracy of the predicted sequence and its controlled chain length. Solubility tests showed favorable results across multiple solvents, highlighting the versatility of the designed polymer. This research underscores the potential of sequence‐defined polyurethanes to emulate the structural and functional attributes of biological macromolecules, opening new pathways for their application in catalysis, drug delivery, and advanced material design. The findings illustrate a promising direction for the development of synthetic polymers with tailored properties, emphasizing the transformative impact of sequence control in polymer chemistry. [ABSTRACT FROM AUTHOR]

Digitally‐encoded poly(phosphodiesters) (d‐PPDE) with highly complex primary structures are evaluated for layer‐by‐layer (LbL) assembly. To be easily decoded by mass spectrometry (MS), these digital polymers contain many different monomers: 2 coding units allowing binary encryption, 1 cleavable spacer allowing controlled MS fragmentation, and 3 mass tags allowing fragment identification. These complex heteropolymers are therefore composed of 6 different motifs. Despite this strong sequence heterogeneity, it is found that they enable a highly controlled LbL film formation. For instance, a regular growth is observed when alternating the deposition of negatively‐charged d‐PPDE and positively‐charged poly(allyl amine hydrochloride) (PAH). Yet, in this approach, the interdistance between consecutive coded d‐PPDE layers remains relatively small, which may be an issue for data storage applications, especially for the selective decoding of the stored information. Using poly(sodium 4‐styrene sulfonate) (PSS) as an intermediate non‐coded polyanion, it is shown that a controlled interdistance between d‐PPDE layers can be easily achieved, while still maintaining a regular LbL growth. Last but not least, it is found in this work that d‐PPDE of relatively small molecular weight (i.e., significantly smaller than those of PAH and PSS) still enables a controlled LbL assembly. [ABSTRACT FROM AUTHOR]

This article explores the impact of different types of mycorrhizal symbiosis on the chemical composition of roots and leaves in temperate woody species. The study found that plants associated with ectomycorrhizal (EcM) fungi had slower decomposition rates and exhibited chemical traits that suppress decomposition compared to plants associated with arbuscular mycorrhizal (AM) fungi. The study also suggests that mycorrhizal associations can influence plant defense responses and the abundance of defense-related phenolic compounds. Another study conducted at the University of Minnesota found that different plant-fungus combinations had significant effects on plant growth and chemical composition. However, the results may not be generalizable to other environmental settings. Another study found that mycorrhizal colonization generally improved plant growth and increased nitrogen content, but the effects on lignin and condensed tannins varied depending on the plant species and type of mycorrhizal fungi. The study also found that mycorrhizal colonization had different effects on lignin molecular composition in gymnosperms and angiosperms. Overall, mycorrhizal colonization can influence the chemical traits and lignin composition of plants, but more research is needed to understand the ecological implications. [Extracted from the article]

Membrane polymers are a promising technology for use in many challenging gas separation applications. The techniques of computer‐aided molecular design can be used to search through the massive molecular space of heteropolymers and develop a set of likely candidate repeat units matching specific physical property targets. However, reasonably accurate property prediction algorithms are needed, but these algorithms must be very fast in order to be combined with an optimization framework. Artificial neural networks (ANNs), a branch of machine learning, are applied in this work to predict the physical properties of polymers. All of the physical properties investigated were found to be predicted by ANNs with R2 scores exceeding 0.82. [ABSTRACT FROM AUTHOR]

This work demonstrates the remodeling of single‐chain nanoparticles (SCNPs) upon a transition to organic solvent through molecular dynamics simulations. Methacrylate‐based random heteropolymers (RHPs), assembled via transient noncovalent linkages in water, have shown promise in an assortment of applications that harness their bio‐inspired properties. While their molecular behavior has been broadly characterized in aqueous environments, many newer applications include the use of organic solvent rather than bio‐mimetic conditions. The polymer assemblies, typically driven by the hydrophobic effect in water, are less well understood in nonaqueous solution. Here, a specific RHP system is examined which forms compact globular morphologies in highly polar or highly nonpolar environments while adopting extended conformations in solvents of intermediate polarity. The pivotal role of electrostatic interactions between charge groups in low dielectric mediums is also observed. Finally, high temperature anneal cycles are compared to room temperature transformations to illuminate barriers to remodeling upon environmental changes. [ABSTRACT FROM AUTHOR]

The flagellar filament is a helical propeller for bacterial locomotion. In external flagellates, the filaments are mostly homopolymers of a single flagellin protein. By contrast, the flagellar filaments of spirochetes are mostly heteropolymers of multiple flagellin proteins. This report seeks to investigate the role of multiple flagellin proteins using the oral spirochete Treponema denticola as a model. First, biochemical and genetic studies uncover that the flagellar filaments of T. denticola mainly comprise four proteins, FlaA, FlaB1, FlaB2, and FlaB3, in a defined stoichiometry. Second, transcriptional analyses reveal that the genes encoding these four proteins are regulated by two different transcriptional factors, sigma28 and sigma70. Third, loss‐of‐function studies demonstrate that each individual flagellin protein contributes to spirochete motility, but none of them is absolutely required. Last, we provide genetic and structural evidence that FlaA forms a "seam"‐like structure around the core and that deletion of individual flagellin protein alters the flagellar homeostasis. Collectively, these results demonstrate that T. denticola has evolved a unique mechanism to finely regulate its flagellar filament gene expression and assembly which renders the organelle with the right number, shape, strength, and structure for its distinct motility. [ABSTRACT FROM AUTHOR]

K‐ion batteries (KIBs) have attracted tremendous attention and seen significant development because of their low price, high operating voltage, and properties similar to those of Li‐ion batteries. In the field of development of full batteries, exploring high‐performing and low‐cost anode materials for K‐ion storage is a crucial challenge. Owing to their excellent cost effectiveness, abundant precursors, and environmental benignancy, hard carbons (HCs) are considered promising anode materials for KIBs. As a result, researchers have devoted much effort to quantify the properties and to understand the underlying mechanisms of HC‐based anodes. In this review, we mainly introduce the electrochemical reaction mechanism of HCs in KIBs, and summarize approaches to further improve the electrochemical performance in HC‐based materials for K‐ion storage. In addition, we also highlight some advanced in situ characterization methods for understanding the evolutionary process underlying the potassiation–depotassiation process, which is essential for the directional electrochemical performance optimization of KIBs. Finally, we raise some challenges in developing smart‐structured HC anode materials for KIBs, and propose rational design principles and perspectives serving as the guidance for the targeted optimization of HC‐based KIBs. [ABSTRACT FROM AUTHOR]

Most of the presently known thermosensitive shape‐memory polymers suitable for 4D printing have insufficient mechanical strength and thermal stability that restricts their potential areas of application. Here, new photosensitive compositions (PSCs) based on aromatic heterochain polymers – poly‐N,N′‐(m‐phenylene)isophthalamide (MPA) or poly‐2,2′‐(p‐oxydiphenylene)‐5,5′‐dibenzimidazole (OPBI) – for DLP printing are proposed. Thermal post‐curing and supercritical carbon dioxide (scCO2) are used for post‐processing of the structures. During the scCO2 treatment the removal of unreacted monomeric component (N,N‐dimethylacrylamide) and its uncrosslinked oligomers is accompanied by the preservation of the initial degree of crosslinking. The more stable shrinkage is observed for the combined post‐processing method (T°+scCO2) in the case of OPBI‐PSC and after the heat treatment for MPA‐PSC specimens. The method of post‐processing and the nature of the heterochain polymer strongly affect the mechanical properties and thermal resistance of the structures. The tensile strength has the maximum value after the thermal post‐treatment (101.1 ± 7.1 and 78.4 ± 5.1 MPa of OPBI‐PSC and MPA‐PSC, respectively). The intense destruction of the materials is observed at 393 and 408 °C for MPA‐PSC and OPBI‐PSC, respectively. Moreover, the 4D‐printed structures exhibit excellent shape memory performance at transition temperatures >100 °C, thus have a great potential for the use in aerospace, robotics, sensorics. [ABSTRACT FROM AUTHOR]

Molybdenum carbide (MoxC) with variable phase structure possesses flexible hydrogen‐binding energy (HBE), which is a promising hydrogen evolution reaction (HER) catalyst. Herein, a hybrid multiphase MoxC freestanding film coupled with Co3Mo (CM/MoxC@NC) is synthesized through the electrospinning method supplemented by the heteroatom incorporation. CM/MoxC@NC surpasses its pure phase counterparts and exhibits remarkable catalytic activity at 114 mV to deliver a current density of 10 mA cm−2 in acid, which is among the first‐rate level performance reported for MoxC‐based catalysts. The subsequent ex situ and in situ characterizations reveal a phase transition mechanism based on self‐catalysis that CoOx depletes the coordinated C of α‐MoC via the interaction, which realizes the assembly of weak HBE α‐MoC and strong HBE β‐Mo2C, and the enhanced utilization of active materials as well. The multiple structures with optimal HBE are in favor of the stepwise reactions of HER, as the study of the correlation between HBE and phase structure revealed. This study discloses the underlying phase transition mechanism and highlights the HBE–structure relationship that should be considered for catalyst design. [ABSTRACT FROM AUTHOR]

Polymerizing and filament‐forming proteins are instrumental for numerous cellular processes such as cell division and growth. Their function in stabilization and localization of protein complexes and replicons is achieved by a filamentous structure. Known filamentous proteins assemble into homopolymers consisting of single subunits – for example, MreB and FtsZ in bacteria – or heteropolymers that are composed of two subunits, for example, keratin and α/β tubulin in eukaryotes. Here, we describe two novel coiled‐coil‐rich proteins (CCRPs) in the filament‐forming cyanobacterium Anabaena sp. PCC 7120 (hereafter Anabaena) that assemble into a heteropolymer and function in the maintenance of the Anabaena multicellular shape (termed trichome). The two CCRPs – Alr4504 and Alr4505 (named ZicK and ZacK) – are strictly interdependent for the assembly of protein filaments in vivo and polymerize nucleotide independently in vitro, similar to known intermediate filament (IF) proteins. A ΔzicKΔzacK double mutant is characterized by a zigzagged cell arrangement and hence a loss of the typical linear Anabaena trichome shape. ZicK and ZacK interact with themselves, with each other, with the elongasome protein MreB, the septal junction protein SepJ and the divisome associate septal protein SepI. Our results suggest that ZicK and ZacK function in cooperation with SepJ and MreB to stabilize the Anabaena trichome and are likely essential for the manifestation of the multicellular shape in Anabaena. Our study reveals the presence of filament‐forming IF‐like proteins whose function is achieved through the formation of heteropolymers in cyanobacteria. [ABSTRACT FROM AUTHOR]

The rapid development of science and technology has brought urgent demand for diversity in polymer structures and functionalities, and the pursuit of new polymerizations and new polymer structures is the constant goal in polymer chemistry. Multicomponent polymerizations and multicomponent reaction involving polymer synthesis have been demonstrated to be a very powerful tool for the construction of functional polymers with diversified structures and advanced functionalities, which have become a prosperous branch of polymer chemistry. Calvo, Wagener, Sumerlin, and co-workers have prepared hyperbranched aminobisphosphonic acid polymers via reversible addition-fragmentation chain transfer self-condensing vinyl polymerization of an acrylamide-functional chain transfer monomer, followed by the introduction of the aminobisphosphonate functional group through a three-component Kabachnick-Fields reaction (2000578). [Extracted from the article]

Heterochain polymers such as DNA and proteins are abundant in nature, but they are not ubiquitous in man‐made polymers due to the synthetic difficulties. Traditional polymerization methodologies including chain polymerization, step‐growth polymerization, and coordination polymerization all show obvious drawbacks in synthesizing heterochain polymers. The alkyne multicomponent polymerizations (MCPs) developed in the early 2000s open a new door for the synthesis of conjugated heterochain polymers with diverse structures and unique properties. This review presents the progress in novel heterochain polymers constructed by alkyne‐based MCPs in the last three years. The unique properties and high‐tech applications brought by heteroatoms and MCPs are summarized and perspectives on future directions are also discussed. [ABSTRACT FROM AUTHOR]

Summary: Fine roots of trees exhibit varying degree of plasticity to adapt to environmental stress. Although the morphological and physiological plasticity of roots has been well studied, less known are the accompanying changes in the chemical composite (chemical plasticity) of fine roots, which regulates both root function and soil carbon sequestration.We investigated the changes in quantity, composition and localization of phenolic compounds in fine root orders of Quercus alba and Quercus rubra subjected to drought stress.In both species the total quantity of lignins varied only by root orders, where the distal (first and second) root orders had lower lignin compared to higher orders. Despite a lower lignin content, the distal root orders had higher content of guaiacyl lignin and bound phenolics that would provide a greater meshing of lignocellulosic matrix, and thus a higher tissue integrity. Unlike lignins, drought altered the quantity and composition of tannins. In Q. alba, the ellagitannins decreased in the distal root orders exposed to drought, while the fiber‐bound condensed tannnins increased. The lower content of ellagitannins with antimicrobial properties under drought reveals an adaptive response by fine roots to promote symbiotic association, as evidenced by the higher colonization of ectomycorrhizal fungi.Our study revealed that, when exposed to drought, the composition of heteropolymers are strategically varied across fine root orders, so as to provide a greater root function without compromising the tissue protection. [ABSTRACT FROM AUTHOR]

The charge density mismatch concept was applied to the synthesis of high‐charge‐density silicoaluminophosphate SAPO‐69 (OFF) and SAPO‐79 (ERI) and zincoaluminophosphate PST‐16 (CGS), PST‐17 (BPH), PST‐19 (SBS), and ZnAPO‐88 (MER) molecular sieves. Combined alkali‐organoammonium structure direction in these systems is thus enabled. Structure direction is treated from the perspective of stabilizing an ionic framework, the relationships between reaction charge density (OH−/H3PO4), alkali and organoammonium content, and ionicity of tetrahedral framework atoms in successful structure direction are presented. [ABSTRACT FROM AUTHOR]

The design of carbon‐based materials with a high mass density and large porosity has always been a challenging goal, since they fulfill the demands of next‐generation supercapacitors and other electrochemical devices. We report a new class of high‐density heteroatom‐doped porous carbon that can be used as an aqueous‐based supercapacitor material. The material was synthesized by an in situ dehalogenation reaction between a halogenated conjugated diene and nitrogen‐containing nucleophiles. Under the given conditions, pyridinium salts can only continue to perform the dehalogenation if there is residue water remaining from the starting materials. The obtained carbon materials are highly doped by various heteroatoms, leading to high densities, abundant multimodal pores, and an excellent volumetric capacitive performance. Porous carbon tri‐doped with nitrogen, phosphorous, and oxygen exhibits a high packing density (2.13 g cm−3) and an exceptional volumetric energy density (36.8 Wh L−1) in alkaline electrolytes, making it competitive to even some Ni‐MH cells. [ABSTRACT FROM AUTHOR]

In this work, unique structures of mulberry‐like Fe/N/S‐doped nanoporous carbon materials (NCMs) are synthesized via a simple self‐assembly assisted process. The Fe2+‐mediated polymerization of dopamine (DA) and further interaction with triblock copolymer F127 micelles induce the formation of mulberry‐like Fe/PDA/F127 structures. After carbonization, the Fe/N/S‐doped NCMs are obtained with a highly porous structure and large Brunauer‐Emmett‐Teller (BET) surface area of 913.2 m2 g−1. Moreover, DA and iron salt introduce active sites, such as Sp2 C, graphitic N, pyridinic N, Fe−Nx, C−S−C, etc. Benefiting from these unique structural features and chemical compositions, the optimized Fe/N/S‐doped NCMs exhibit enhanced electrocatalytic activity and excellent durability for oxygen reduction reaction (ORR) compared with commercial Pt/C catalyst. These studies provide not only a new synthesis method for heteroatom‐doped NCMs, but also a platform for various applications. Nanoporous mulberry‐like Fe/N/S‐doped carbon materials were synthesized using a facile and green self‐assembly synthesis method. The atomic iron and high effective N/S‐doping synergistically enhanced the ORR activity. The obtained catalysts possess a high BET surface area of 913.2 m2 g−1 and exhibit higher activity, stability, and methanol resistance than commercial Pt/C for ORR. [ABSTRACT FROM AUTHOR]

There are various nonplanar heteroatom analogues of benzene—cyclic 6π electron systems—and among them, hexasilabenzene (Si6H6) is well known as a typical example. To determine the factors that control their planarity, quantum chemical calculations and an energy component analysis were performed. The results show that the energy components mainly controlling the planarity of benzene and hexasilabenzene are different. For hexasilabenzene, electron repulsion energy was found to be significantly important for the planarity. The application of the pseudo Jahn–Teller effect and the Carter–Goddard–Malrieu–Trinquier model for the interpretation of the planarity of the benzene analogues was also investigated. Furthermore, based on the quantitative results, it was revealed that the planarization of hexasilabenzene is realized by introducing substituents with π‐accepting ability, such as the boryl group, that bring about a reduction of the π‐electron repulsion on the silicon skeleton. © 2018 Wiley Periodicals, Inc. Hexasilabenzene (Si6H6) is well‐known as a typical example of nonplanar heteroatom analogues of benzene. The present study shows that the energy factors mainly controlling the planarity of benzene and hexasilabenzene are different. Based on the quantitative results, some strategies to systematically control the planarity of hexasilabenzene, such as utilizing the substituent effect, are suggested. [ABSTRACT FROM AUTHOR]

Nickel‐heteroatoms bridge sites are important reaction descriptors for many catalytic and electrochemical processes. Herein we report the controllable surface modification of nickel–nitrogen (Ni−N) bridge sites on metallic Ni particles via a simplified vapor‐assisted treatment approach. X‐ray absorption spectroscopy (XAS) and Operando Raman spectroscopy verifies the interaction between Ni and surface‐anchored N, which leads to distorted Ni lattice structure with improved wettability. The Ni−N bridge sites with appropriate N coverage level plays a critical role in the enhanced hydrogen evolution reaction (HER) and the optimized electrode (Ni−N0.19) has demonstrated superior HER performances with low overpotential merely of 42 mV for achieving a current density of 10 mA cm−2, as well as favorable reaction kinetics and excellent durability in alkaline electrolyte. DFT calculations revealed that the appropriate N‐coverage level can lead to the most favorable ΔGH* kinetics for both adsorption of H* and release of H2, while high N coverage (Ni−N0.59) results in weaker H* adsorption, thus a decreased HER activity, corresponding well to our experimental observations. Furthermore, this generic synthetic approach can also be applied to prepare S‐modified Ni HER catalyst by generating hydrogen sulfide vapor. [ABSTRACT FROM AUTHOR]

Diketopyrrolopyrrole (DPP) derivatives are promising compounds for application in organic electronics. Here, we investigate several symmetrical N‐unsubstituted and N‐methyl substituted DPPs which differ in the heteroatom in the aromatic flanks. The conformational, electronic, and optical properties are characterized for single molecules in vacuum or a solvent. The intermolecular interactions are evaluated for interacting dimers. Here, a number of stacking geometries is tested, and dimers with mutual orientation of the molecules corresponding to the minimal binding energies are determined. The predicted charge carrier mobilities for stacks having minimal binding energies corroborate experimentally measured values. We conclude that DFT prediction of such stacks is a promising and computationally inexpensive approach to a rough estimation of transport properties. Additionally, the super‐cell of the experimentally resolved crystal structure is used to study the dynamics and to compute the charge transport along the hopping pathways. We discuss obtained high mobilities and relate them to the symmetry of DPP core. © 2018 Wiley Periodicals, Inc. Small symmetric conjugated molecules with diketopyrrolopyrrole core decorated by thiophene or furan aromatic rings are modeled with atomistic details in DFT/MD simulations. The calculation of stacks of two identical molecules characterizing by the lowest binding energy is considered as a promising, computationally inexpensive approach to a rough estimation of the electronic coupling. The molecular dynamics simulation of DPP crystal at room temperature provides the carrier mobilities in all possible hopping pathways. [ABSTRACT FROM AUTHOR]

The structural diversity and tenability observed in POMs has encouraged extensive investigations into their catalytic activity. Based on the structural classification of POMs, this review summarizes recent advances relating to POM-catalyzed selective oxidation and places most emphasis on dynamic developments from 2015 onwards. Work which contributes to comparing the catalytic performance of POMs with delicate structural differences (e.g. the same type of POM structure with differences of the heteroatom, addenda, protonated state or counter-ion) and in elucidating the origin/distinction of catalytic activity, as well as reasonable mechanisms, are especially highlighted. [ABSTRACT FROM AUTHOR]

Cycloparaphenylenes (CPPs) have attracted significant attention from theoretical, synthetic, supramolecular and material chemists owing to their aesthetical structures. Since Jasti and co‐workers reported the landmark synthesis of [9]CPP, [12]CPP and [18]CPP, the past ten years have witnessed a remarkable burst in the development of CPP research, from synthetic methodologies to the applications in optoelectronic devices. In this Focus Review, we highlight the representative synthetic strategies to CPPs and attempts on bottom‐up synthesis of carbon nanotubes (CNTs), and mainly focus on the optoelectronic properties studies of functionalized CPPs as well as heteroatoms doped CPP derivatives. Additionally, the potential applications of CPP derivatives in material science are discussed. Carbon nanohoops: Cycloparaphenylenes (CPPs) have attracted significant attention from theoretical, synthetic, supramolecular and material chemists in the past decade. This Focus Review highlights the representative synthetic strategies to CPPs, providing an overview of recent advances in the synthesis and property investigations of CPPs and its derivatives. The potential applications of CPPs have been discussed as well. [ABSTRACT FROM AUTHOR]

In this work, we introduce an approximate method for the multicenter index calculation that is very simple in implementation and has the same computational cost as the pseudo‐π approach. In contrast to the latter, however, the newly proposed method does not require additional single‐point calculations and is capable of quantifying multicenter electron sharing in aromatic rings containing heteroatoms and transition metals. [ABSTRACT FROM AUTHOR]

Abstract: Palladium nanoparticles stabilized by heteroatom donor‐modified polystyrene‐based polymer immobilized ionic liquids (PdNP@HAD‐PIILP; HAD‐PPh2, OMe, NH2, CN, pyrrolidone) are highly efficient catalysts for the Suzuki‐Miyaura cross‐coupling in aqueous media under mild conditions. Catalyst modified with phosphine was consistently the most efficient as it gave high yields across a range of substrates under mild conditions at low catalyst loadings. Incorporation of polyethylene glycol into the phosphine modified immobilised ionic liquid support improved catalyst efficacy by improving dispersibility and facilitating access to the active site. Moreover, each of the heteroatom modified catalysts was more active than the corresponding unsubstituted imidazolium‐based polystyrene benchmark as well as commercial samples of Pd/C. Catalyst generated in situ from either [PdCl4]@PPh2‐PIILP or its PEGylated counterpart [PdCl4]@PPh2‐PEGPIILP, by reduction with phenylboronic acid, outperformed their pre‐formed counterparts for the vast majority of substrates examined. The turnover frequency of 16,300 h−1 obtained at room temperature is one of the highest to be reported for palladium nanoparticle‐catalysed Suzuki‐Miyaura cross‐coupling between 4‐bromoacetophenone and phenylboronic acid in aqueous media under such mild conditions. [ABSTRACT FROM AUTHOR]

The effective dehydration of glucose to 5‐hydroxymethylfurfural (HMF) has attracted increasing attention. Herein, a series of sulfonic‐acid‐functionalized ionic liquid (IL)–heteropolyacid (HPA) hybrid catalysts are proposed for the conversion of glucose to HMF. A maximum total yield of HMF and levoglucosan (LGA; ≈71 %) was achieved in the presence of pyrazine IL‐HPA hybrid catalyst [PzS]H2PW in THF/H2O–NaCl (v/v 5:1). The mechanism of glucose dehydration was studied by tailoring the Brønsted/Lewis acid sites of the hybrid catalysts and altering the solvent composition. It was found that water and heteropolyanions have a significant effect on the reaction kinetics. Heteropolyanions are able to stabilize the intermediates and promote the direct dehydration of glucose and intermediate LGA to HMF. A small amount of water could facilitate the conversion of glucose to LGA and suppress the dehydration of LGA to levoglucosenone. In addition, the synergetic effect of Brønsted/Lewis acid sites and a little water was conducive to accelerated proton transfer, which improved the yield of HMF from glucose dehydration. Go direct to HMF: A small amount of water and heteropolyanions affect the reaction pathways of glucose dehydration to 5‐hydroxymethylfurfural (HMF) with heteropolyacid (HPA)‐based ionic hybrid catalysts (see scheme). Hydrogen bonds between the substrate, water, and the catalyst and ionic interactions in the catalyst stabilize the reaction intermediates and accelerate proton transfer, which results in direct conversion of glucose and levoglucosan (LGA) into HMF. [ABSTRACT FROM AUTHOR]

Abstract: This report widens the repertoire of emerging PdI catalysis to carbon–heteroatom, that is, C−S bond formation. While Pd0‐catalyzed protocols may suffer from the formation of poisonous sulfide‐bound off‐cycle intermediates and lack of selectivity, the mechanistically diverse PdI catalysis concept circumvents these challenges and allows for C−S bond formation (S–aryl and S–alkyl) of a wide range of aryl halides. Site‐selective thiolations of C−Br sites in the presence of C−Cl and C−OTf were achieved in a general and a priori predictable fashion. Computational, spectroscopic, X‐ray, and reactivity data support dinuclear PdI catalysis to be operative. Contrary to air‐sensitive Pd0, the active PdI species was easily recovered in the open atmosphere and subjected to multiple rounds of recycling. [ABSTRACT FROM AUTHOR]

Abstract: A key challenge of photoregulated living radical polymerization is developing efficient and robust photocatalysts. Now carbon dots (CDs) have been exploited for the first time as metal‐free photocatalysts for visible‐light‐regulated reversible addition–fragmentation chain‐transfer (RAFT) polymerization. Screening of diverse heteroatom‐doped CDs suggested that the P‐ and S‐doped CDs were effective photocatalysts for RAFT polymerization under mild visible light following a photoinduced electron transfer (PET) involved oxidative quenching mechanism. PET‐RAFT polymerization of various monomers with temporal control, narrow dispersity (Đ≈1.04), and chain‐end fidelity was achieved. Besides, it was demonstrated that the CD‐catalyzed PET‐RAFT polymerization was effectively performed under natural solar irradiation. [ABSTRACT FROM AUTHOR]

Abstract: The insertion of heteroatoms with different electronegativity into carbon materials can tune their chemical, electronic, and optical properties. However, in traditional solid‐state synthesis, it is challenging to control the reactivity of monomers, and therefore, the amount and position of heteroatoms in the final materials. Herein, a simple, scalable, and general molten‐state route to synthesize boron–nitrogen–carbon–oxygen (BNCO) materials with tunable boron–nitrogen–carbon composition, as well as electronic and optical properties, is reported. The new synthetic approach consists of polycyclic aromatic hydrocarbons (PAHs) and ammonia–borane as reactants that form a clear liquid‐state stage spanning a wide temperature range, before the solid‐state reaction. The molten‐state stage enhances the control over the synthetic intermediates and final materials, owing to improved monomer miscibility and reactivity. The BNCO composition and optical properties are tuned by the PAH selection and final reaction temperature. The advantages of this method are demonstrated herein through the tunable optical properties, excellent stability to oxidization, facile deposition on substrates, and good activity as an anode material in lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Thiourea‐modified wood‐based activated carbon materials were evaluated as catalysts for the CO2 electrochemical reduction reaction (CO2ERR). The materials obtained at 950 °C showed long‐term stability. The results indicated that thiophenic sulfur provides the catalytic activity for CO formation. However, it was not as active for CH4 formation as was pyridinic N. Tafel plots suggested that the nanoporous structure enhanced the kinetics for CO2 reduction. The electric conductivity limited the activity for CO2ERR in the materials modified at 600, 800, and 900 °C. The effect of visible light on CO2ERR was also investigated in this study. Upon irradiation, photocurrent was generated, and the current density increased during the CO2 reduction process. Combined with a band‐gap alignment, the results indicate that thiophenic S in the carbon matrix contributed to the sample's photoactivity in visible light. These species enhance the overall reduction process, promoting both the hydrogen evolution reaction and CO2 reduction to CO. [ABSTRACT FROM AUTHOR]

Abstract: We have developed an efficient ligand‐free copper‐catalyzed regio‐ and stereoselective carbo‐borylation of heteroatom‐substituted internal alkynes using bis(pinacolato)diboron as boron source and alkyl halides as an electrophile. Both chemical yields and functional group tolerance are excellent. Our method provides an efficient synthesis of tri‐ and tetra‐substituted alkenylboronates which could be further transformed to highly substituted alkenes via subsequent cross‐coupling reactions in one pot. [ABSTRACT FROM AUTHOR]

Abstract: Most of compounds containing more than one reactive groups may produce several byproducts during the coupling process. Selective carbon‐heteroatom coupling reactions, which have merits of high synthetic efficiency and step economy, are the best choice to resolve the problem. Although they have made great progress, they deserve further exploration. This review discusses their recent advances and intend to inspire the research in the future. It is organized on the basis of selective carbon‐heteroatom coupling reaction types, including selective C−N and C−N, C−N and C−O, C−O and C−O, C−C and C−N coupling reactions. [ABSTRACT FROM AUTHOR]

Abstract: An activation step is essential for yielding nitrogen‐doped mesoporous carbon (NMCs) oxygen reduction reaction (ORR) electrocatalysts from biomass. Though many solely KOH or ZnCl2 activated carbon materials have been synthesized with fine ORR activity, there a deep discussion of activated‐carbon‐based electrocatalysts obtained from different activation processes is still lacking. In this paper, we systemically compare radish‐derived NMCs that underwent different activation processes, and reveal the relationship between structure and activity of these activated carbons. We showed that though ZnCl2 is not an effective porogen compared with KOH, owing to a more open pore structure along with effective preservation of nitrogen heteroatoms, ZnCl2 assisted activated carbon could show significantly improved ORR activity, with an onset potential of 0.91 V (vs. RHE), close to benchmark Pt/C catalysts and even better extended operation stability and stronger tolerance to methanol crossover compared with commercial Pt/C catalysts. Thus we proved that ZnCl2 assisted activation is better than exclusively self‐activation or KOH assisted activation in preparing biomass‐derived ORR catalysts. [ABSTRACT FROM AUTHOR]

Abstract: The growing energy and environmental crisis calls for renewable systems for energy production and conversion. Herein, polyaniline‐derived porous carbon nanorods tri‐doped with N, P, and S (NPSC) are directly fabricated by the one‐pot polymerization of aniline and diphenylamine‐4‐sulfonic acid induced by organophosphonic acid and subsequent pyrolysis at 900 °C. The nanorods exhibit high‐efficiency electrochemical oxygen reduction and oxygen evolution activity in alkaline electrolyte, along with strong durability and methanol tolerance. The synergistic effect among the tri‐doped elements and the related porosity can account for the superior electrocatalytic capacity of the fabricated catalysts. Particularly, a Zn–air battery assembled with the fabricated NPSC as the cathode shows a peak power density of 122 mW cm−2 and superior stability, presenting a promising potential for sustainable energy devices, particularly regenerative metal–air batteries and fuel cells. [ABSTRACT FROM AUTHOR]

Abstract: Three new star‐shaped hole‐transporting materials (HTMs) incorporating benzotripyrrole, benzotrifuran, and benzotriselenophene central cores endowed with three‐armed triphenylamine moieties (BTP‐1, BTF‐1, and BTSe‐1, respectively) are designed, synthesized, and implemented in perovskite solar cells (PSCs). The impact that the heteroatom‐containing central scaffold has on the electrochemical and photophysical properties, as well as on the photovoltaic performance, is systematically investigated and compared with their sulfur‐rich analogue (BTT‐3). The new HTMs exhibit suitable highest‐occupied molecular orbitals (HOMO) levels regarding the valence band of the perovskite, which ensure efficient hole extraction at the perovskite/HTM interface. The molecular structures of BTF‐1, BTT‐3, and BTSe‐1 are fully elucidated by single‐crystal X‐ray crystallography as toluene solvates. The optimized (FAPbI3)0.85(MAPbBr3)0.15‐based perovskite solar cells employing the tailor‐made, chalcogenide‐based HTMs exhibit remarkable power conversion efficiencies up to 18.5%, which are comparable to the devices based on the benchmark spiro‐OMeTAD. PSCs with BTP‐1 exhibit a more limited power conversion efficiency of 15.5%, with noticeable hysteresis. This systematic study indicates that chalcogenide‐based derivatives are promising HTM candidates to compete efficiently with spiro‐OMeTAD. [ABSTRACT FROM AUTHOR]

ABSTRACT: A new approach to making a photopolymeric composition was first elaborated in this work based on the use of poly‐N,N′‐(m‐phenylene)isophtalamide as the heterochain polymer matrix together with 4,4′‐diphenyl oxide diacrylamide as the crosslinking agent. Reproducible three‐dimensional (3D) objects have been formed using a laser stereolithograph completed with a laser with wavelength of 405 nm. According to the thermogravimetric analysis, the thermal stability of the formed objects could be changed through a control from 260 to 405 °C. Moreover, it was proven that the tensile strength of samples of the crosslinked films reached 90.1 ± 3.2 MPa at the elongation at break of 12.4 ± 2.3%, depending on the forming parameters of such samples. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46463. [ABSTRACT FROM AUTHOR]

Abstract: Transition metal‐catalyzed decarbonylative coupling reactions have emerged as a powerful alternative to conventional cross‐coupling protocols due to the advantages associated with the use of carbonyl‐containing functionalities as coupling electrophiles instead of commonly used organohalides or sulfates. A wide variety of novel transformations based on this concept have been successfully achieved, including decarbonylative carbon–carbon and carbon–heteroatom bond forming reactions. In this Review, we summarize the recent progress in this field and present a comprehensive overview of metal‐catalyzed decarbonylative coupling reactions with carbonyl derivatives. [ABSTRACT FROM AUTHOR]

Abstract: Pybox ligands have found widespread application in organic synthesis and catalysis ever since their discovery, and their involvement in various C−C and C–heteroatom bond‐forming reactions is rapidly increasing. In this Focus Review, we summarise the reactions involving various Pybox–metal combinations used for forming C−C bonds, such as cross‐coupling reactions, carbonyl–ene reactions, three‐component reactions, allylation reactions, Diels–Alder reactions and other C−C bond‐forming reactions. The literature from 2006 to 2017 is covered. [ABSTRACT FROM AUTHOR]

Pt/Co and Au are organized into well-defined nanostructures by a simple and mild method, such as dumbbell-like nanorods and core-shell nanorods. The resultant dumbbell-like nanorods show a superior performance in the electrooxidation of formic acid, as compared with core-shell nanorods, Pt-tipped gold nanorods, and commercial Pt/C. This result can be attributed to electronic effect between Au and Pt, heteroatom effect of Co, irregular surface at the tips, and the interface effect. [ABSTRACT FROM AUTHOR]

Abstract: π‐Coordinating ligands are commonly found in intermediate structures in homogeneous catalysis, and are gaining interest as supporting ligands for the development of cooperative catalysts. Herein, we systematically investigate the binding of the ketone group, a strongly accepting π ligand, to mid‐to‐late metals of the first transition series. To this end, the coordination of 2,2′‐bis(diphenylphosphino)benzophenone (Phdpbp), which features a ketone moiety flanked by two strongly binding P‐donor groups, to Fe, Co, Ni, and Cu was explored. The ketone moiety does not bind to the metal in MII complexes, whereas MI complexes (Fe, Co, Ni) adopt an η2(C,O) coordination. A structural and computational investigation of periodic trends in this series was performed. These data suggest that the coordination of the ketone to MI can mostly be described by the resonance extremes of the Dewar–Chatt–Duncanson model, that is, the π complex and the metallaoxacycle extreme, with a possible minor contribution from a ketyl radical resonance structure in the case of the iron complex. [ABSTRACT FROM AUTHOR]

Abstract: On‐surface synthesis shows significant potential in constructing novel nanostructures/nanomaterials, which has been intensely studied in recent years. The formation of acetylenic scaffolds provides an important route to the fabrication of emerging carbon nanostructures, including carbyne, graphyne, and graphdiyne, which feature chemically vulnerable sp‐hybridized carbon atoms. Herein, we designed and synthesized a tribromomethyl‐substituted compound. By using a combination of high‐resolution scanning tunneling microscopy, non‐contact atomic force microscopy, and density functional theory calculations, we demonstrated that it is feasible to convert these compounds directly into C−C triple‐bonded structural motifs by on‐surface dehalogenative homocoupling reactions. Concurrently, sp3‐hybridized carbon atoms are converted into sp‐hybridized ones, that is, an alkyl group is transformed into an alkynyl moiety. Moreover, we achieved the formation of dimer structures, one‐dimensional molecular wires, and two‐dimensional molecular networks on Au(111) surfaces, which should inspire further studies towards two‐dimensional graphyne structures. [ABSTRACT FROM AUTHOR]

Abstract: Boron‐graphdiyne (BGDY), which has a unique π‐conjugated structure comprising an sp‐hybridized carbon skeleton and evenlydistributed boron heteroatoms in a well‐organized 2D molecular plane, is prepared through a bottom‐up synthetic strategy. Excellent conductivity, a relatively low band gap and a packing mode of the planar BGDY are observed. Notably, the unusual bonding environment of the all sp‐carbon framework and the electron‐deficient boron centers generates affinity to metal atoms, and thus provides extra binding sites. Furthermore, the expanded molecule pores of the BGDY molecular plane can also facilitate the transfer of metal ions in the perpendicular direction. The practical effect of the all sp‐carbon structure and boron heteroatoms on the properties of BGDY are demonstrated in its performance as the anode in sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Sodium‐ion batteries are attracting much interest due to their potential as viable future alternatives for lithium‐ion batteries, in view of the much higher earth abundance of sodium over that of lithium. Although both battery systems have basically similar chemistries, the key celebrated negative electrode in lithium battery, namely, graphite, is unavailable for the sodium‐ion battery due to the larger size of the sodium ion. This need is satisfied by “hard carbon”, which can internalize the larger sodium ion and has desirable electrochemical properties. Unlike graphite, with its specific layered structure, however, hard carbon occurs in diverse microstructural states. Herein, the relationships between precursor choices, synthetic protocols, microstructural states, and performance features of hard carbon forms in the context of sodium‐ion battery applications are elucidated. Derived from the pertinent literature employing classical and modern structural characterization techniques, various issues related to microstructure, morphology, defects, and heteroatom doping are discussed. Finally, an outlook is presented to suggest emerging research directions. [ABSTRACT FROM AUTHOR]

Abstract: In this Concept article, we will scrutinize different approaches devoted to the mechanistic understanding of catalytic processes, paying special attention to the successful use of triazamacrocyclic aryl‐halide or arene‐containing substrates used for Cu‐, Ag‐, Au‐, Co‐ and Ni‐catalysis. The importance of designing model substrate platforms to unravel mechanistic details at a molecular level of C−C or C‐heteroatom bond‐forming processes catalyzed by transition metals will be highlighted. This fundamental mechanistic knowledge will serve as a foundation for the catalyst design for a desired transformation. [ABSTRACT FROM AUTHOR]

Abstract: The properties of graphene nanoribbons are highly dependent on structural variables such as width, length, edge structure, and heteroatom doping. Therefore, atomic precision over all these variables is necessary for establishing their fundamental properties and exploring their potential applications. An iterative approach is presented that assembles a small and carefully designed molecular building block into monodisperse N‐doped graphene nanoribbons with different lengths. To showcase this approach, the synthesis and characterisation of a series of nanoribbons constituted of 10, 20 and 30 conjugated linearly‐fused rings (2.9, 5.3, and 7.7 nm in length, respectively) is presented. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of SFE‐type borosilcate zeolite was successfully carried out using a commercially available low‐cost organic structure directing agent (OSDA) with ultra‐low OSDA and water contents within a short crystallization time. Heteroatom (Al, Ti, V, or Fe)‐substituted SFE‐type zeolite analogues were also directly synthesized for the first time. The obtained Al containing zeolites exhibited promising catalytic performances in the disproportionation of isopropylnaphthalene. [ABSTRACT FROM AUTHOR]

Boron and copper heteroatoms were successfully incorporated into the frameworks of high-silica RHO zeolite by adopting a bulky alkali-metal-crown ether (AMCE) complex as the template. These heteroatom-doped zeolites show both larger micropore surface areas and volumes than those of their aluminosilicate analogue. Proton-type RHO zeolites were then applied for the separation of CO2/CH4/N2 mixtures, as these zeolites have weaker electric fields and, thus, lower heats of adsorption. The adsorption results showed that a balance between working capacity and adsorption heat could be achieved for these heteroatom-doped zeolites. Ideal adsorbed solution theory predictions indicate that these zeolites should have high selectivities even for remarkably dilute sources of CO2. Finally, the heteroatom-substituted zeolites, especially the boron-substituted one, could be thermally regenerated rapidly at 150 °C after full hydration and maintained high regenerability for up to 30 cycles; therefore, they are potential candidates for trace CO2 removal under humid conditions. [ABSTRACT FROM AUTHOR]

Various advanced catalysts based on sulfur-doped Fe/N/C materials have recently been designed for the oxygen reduction reaction (ORR); however, the enhanced activity is still controversial and usually attributed to differences in the surface area, improved conductivity, or uncertain synergistic effects. Herein, a sulfur-doped Fe/N/C catalyst (denoted as Fe/SNC) was obtained by a template-sacrificing method. The incorporated sulfur gives a thiophene-like structure (C−S−C), reduces the electron localization around the Fe centers, improves the interaction with oxygenated species, and therefore facilitates the complete 4 e− ORR in acidic solution. Owing to these synergistic effects, the Fe/SNC catalyst exhibits much better ORR activity than the sulfur-free variant (Fe/NC) in 0.5 m H2SO4. [ABSTRACT FROM AUTHOR]

Hard carbon is the leading candidate anode for commercialization of Na-ion batteries. Hard carbon has a unique local atomic structure, which is composed of nanodomains of layered rumpled sheets that have short-range local order resembling graphene within each layer, but complete disorder along the c-axis between layers. A primary challenge holding back the development of Na-ion batteries is that a complete understanding of the structure-capacity correlations of Na-ion storage in hard carbon has remained elusive. This article presents two key discoveries: first, the characteristics of hard carbons structure can be modified systematically by heteroatom doping, and second, that these structural changes greatly affect Na-ion storage properties, which reveals the mechanisms for Na storage in hard carbon. Specifically, via P or S doping, the interlayer spacing is dilated, which extends the low-voltage plateau capacity, while increasing the defect concentrations with P or B doping leads to higher sloping sodiation capacity. The combined experimental studies and first principles calculations reveal that it is the Na-ion-defect binding that corresponds to the sloping capacity, while the Na intercalation between graphenic layers causes the low-potential plateau capacity. The understanding suggests a new design principle of hard carbon anode: more reversibly binding defects and dilated turbostratic domains, given that the specific surface area is maintained low. [ABSTRACT FROM AUTHOR]

The heteroatoms such as nitrogen, oxygen, and sulfur of organic inhibitor play a crucial role on its corrosion inhibition behavior. In order to reveal their adsorption behavior and inhibition performance under illumination condition on steel surface, this study selects L-cysteine as study object. On the basis of electrochemical measurement, surface analysis, and theoretical calculation, a promising increase in corrosion inhibition efficiency is observed when visible-light is impinged on steel surface in sodium chloride solution with L-cysteine. The enhanced performance is attributed to the sample surface photovoltaic effect, thereby facilitating both the thiol and the amino groups to tilt toward the surface. [ABSTRACT FROM AUTHOR]

Fuel cells, water electrolyzers, and metal-air batteries are important energy systems that have started to play some roles in our renewable energy landscapes. However, despite much research works carried out on them, they have not yet found large-scale applications, mainly due to the unavailability of sustainable catalysts that can catalyze the reactions employed in them. Currently, noble metal-based materials are the ones that are commonly used as catalysts in most commercial fuel cells, electrolyzers, and metal-air batteries. Hence, there has been considerable research efforts worldwide to find alternative noble metal-free and metal-free catalysts composed of inexpensive, earth-abundant elements for use in the catalytic reactions employed in these energy systems. In this concept paper, a brief introduction on catalysis in renewable energy systems, followed by the recent efforts to develop sustainable, heteroatom-doped carbon and non-noble metal-based electrocatalysts, the challenges to unravel their structure-catalytic activity relationships, and the authors' perspectives on these topics and materials, are discussed. [ABSTRACT FROM AUTHOR]

Macrocycle ligands have three or more donor sites. Selective replacement of skeleton carbon atoms by heteroatoms and vacancies in C60 could lead to various macrocycle ligands with a cage-shaped backbone. Theoretical calculations indicate that such C60-based macrocycle ligands are as stable as C60 thermodynamically according to their similar HOMO-LUMO gaps. The synthesis of these ligands is a challenging task. Nevertheless important progresses have been reported. This concept article focuses on the structures of possible C60-based macrocycle ligands and related synthetic results. [ABSTRACT FROM AUTHOR]