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    1 OF 86

    Multiscale and Multistep Ordering of Flow-Induced Nucleation of Polymers.
    Chem Rev 2018 Jan 19. Epub 2018 Jan 19.
    National Synchrotron Radiation Laboratory, Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry, and Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film, University of Science and Technology of China , 96 Jinzhai Road, Baohe District, Hefei 230026, People's Republic of China.
    Flow-induced crystallization (FIC) is a typical nonequilibrium phase transition and a core industry subject for the largest group of commercially useful polymeric materials: semicrystalline polymers. A fundamental understanding of FIC can benefit the research of nonequilibrium ordering in matter systems and help to tailor the ultimate properties of polymeric materials. Concerning the crystallization process, flow can accelerate the kinetics by orders of magnitude and induce the formation of oriented crystallites like shish-kebab, which are associated with the major influences of flow on nucleation, that is, raised nucleation density and oriented nuclei. Read More

    Oxygen Activation and Energy Conservation by Cytochrome c Oxidase.
    Chem Rev 2018 Jan 19. Epub 2018 Jan 19.
    Institute of Biotechnology, University of Helsinki , P.O. Box 56, Helsinki FI-00014, Finland.
    This review focuses on the type A cytochrome c oxidases (CcO), which are found in all mitochondria and also in several aerobic bacteria. CcO catalyzes the respiratory reduction of dioxygen (O2) to water by an intriguing mechanism, the details of which are fairly well understood today as a result of research for over four decades. Perhaps even more intriguingly, the membrane-bound CcO couples the O2 reduction chemistry to translocation of protons across the membrane, thus contributing to generation of the electrochemical proton gradient that is used to drive the synthesis of ATP as catalyzed by the rotary ATP synthase in the same membrane. Read More

    Bright Side of Lignin Depolymerization: Toward New Platform Chemicals.
    Chem Rev 2018 Jan 16. Epub 2018 Jan 16.
    Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
    Lignin, a major component of lignocellulose, is the largest source of aromatic building blocks on the planet and harbors great potential to serve as starting material for the production of biobased products. Despite the initial challenges associated with the robust and irregular structure of lignin, the valorization of this intriguing aromatic biopolymer has come a long way: recently, many creative strategies emerged that deliver defined products via catalytic or biocatalytic depolymerization in good yields. The purpose of this review is to provide insight into these novel approaches and the potential application of such emerging new structures for the synthesis of biobased polymers or pharmacologically active molecules. Read More

    Engineering the Surface of Therapeutic "Living" Cells.
    Chem Rev 2018 Jan 16. Epub 2018 Jan 16.
    Department of Prosthodontics and Dental Research Institute, School of Dentistry, Seoul National University , Seoul 110-749, Korea.
    Biological cells are complex living machines that have garnered significant attention for their potential to serve as a new generation of therapeutic and delivery agents. Because of their secretion, differentiation, and homing activities, therapeutic cells have tremendous potential to treat or even cure various diseases and injuries that have defied conventional therapeutic strategies. Therapeutic cells can be systemically or locally transplanted. Read More

    Same Substrate, Many Reactions: Oxygen Activation in Flavoenzymes.
    Chem Rev 2018 Jan 11. Epub 2018 Jan 11.
    Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia , Via Ferrata 9, 27100 Pavia, Italy.
    Over time, organisms have evolved strategies to cope with the abundance of dioxygen on Earth. Oxygen-utilizing enzymes tightly control the reactions involving O2 mostly by modulating the reactivity of their cofactors. Flavins are extremely versatile cofactors that are capable of undergoing redox reactions by accepting either one electron or two electrons, alternating between the oxidized and the reduced states. Read More

    Using Genome Sequence to Enable the Design of Medicines and Chemical Probes.
    Chem Rev 2018 Jan 11. Epub 2018 Jan 11.
    Departments of Chemistry and Neuroscience, The Scripps Research Institute , 130 Scripps Way, Jupiter, Florida 33458, United States.
    Rapid progress in genome sequencing technology has put us firmly into a postgenomic era. A key challenge in biomedical research is harnessing genome sequence to fulfill the promise of personalized medicine. This Review describes how genome sequencing has enabled the identification of disease-causing biomolecules and how these data have been converted into chemical probes of function, preclinical lead modalities, and ultimately U. Read More

    Electrostatic Interactions in Protein Structure, Folding, Binding, and Condensation.
    Chem Rev 2018 Jan 10. Epub 2018 Jan 10.
    Department of Physics and Institute of Molecular Biophysics, Florida State University , Tallahassee, Florida 32306, United States.
    Charged and polar groups, through forming ion pairs, hydrogen bonds, and other less specific electrostatic interactions, impart important properties to proteins. Modulation of the charges on the amino acids, e.g. Read More

    Homogeneously Catalyzed Electroreduction of Carbon Dioxide-Methods, Mechanisms, and Catalysts.
    Chem Rev 2018 Jan 10. Epub 2018 Jan 10.
    Lehrstuhl für Theoretische Chemie, Ruhr-University Bochum , 44780 Bochum, Germany.
    The utilization of CO2 via electrochemical reduction constitutes a promising approach toward production of value-added chemicals or fuels using intermittent renewable energy sources. For this purpose, molecular electrocatalysts are frequently studied and the recent progress both in tuning of the catalytic properties and in mechanistic understanding is truly remarkable. While in earlier years research efforts were focused on complexes with rare metal centers such as Re, Ru, and Pd, the focus has recently shifted toward earth-abundant transition metals such as Mn, Fe, Co, and Ni. Read More

    Advances in One-Pot Synthesis through Borrowing Hydrogen Catalysis.
    Chem Rev 2018 Jan 10. Epub 2018 Jan 10.
    Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas , Avenida Los Naranjos s/n, 46022 Valencia, Spain.
    The borrowing hydrogen (BH) principle, also called hydrogen auto-transfer, is a powerful approach which combines transfer hydrogenation (avoiding the direct use of molecular hydrogen) with one or more intermediate reactions to synthesize more complex molecules without the need for tedious separation or isolation processes. The strategy which usually relies on three steps, (i) dehydrogenation, (ii) intermediate reaction, and (iii) hydrogenation, is an excellent and well-recognized process from the synthetic, economic, and environmental point of view. In this context, the objective of the present review is to give a global overview on the topic starting from those contributions published prior to the emergence of the BH concept to the most recent and current research under the term of BH catalysis. Read More

    Green and Sustainable Solvents in Chemical Processes.
    Chem Rev 2018 Jan 4. Epub 2018 Jan 4.
    Department of Chemical Engineering, Imperial College , London SW7 2AZ, United Kingdom.
    Sustainable solvents are a topic of growing interest in both the research community and the chemical industry due to a growing awareness of the impact of solvents on pollution, energy usage, and contributions to air quality and climate change. Solvent losses represent a major portion of organic pollution, and solvent removal represents a large proportion of process energy consumption. To counter these issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Read More

    RNA Structural Dynamics As Captured by Molecular Simulations: A Comprehensive Overview.
    Chem Rev 2018 Jan 3. Epub 2018 Jan 3.
    Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc , 17. listopadu 12, Olomouc 771 46, Czech Republic.
    With both catalytic and genetic functions, ribonucleic acid (RNA) is perhaps the most pluripotent chemical species in molecular biology, and its functions are intimately linked to its structure and dynamics. Computer simulations, and in particular atomistic molecular dynamics (MD), allow structural dynamics of biomolecular systems to be investigated with unprecedented temporal and spatial resolution. We here provide a comprehensive overview of the fast-developing field of MD simulations of RNA molecules. Read More

    Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies.
    Chem Rev 2018 Jan 2. Epub 2018 Jan 2.
    Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.
    Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges. Read More

    Oxygen Activation and Radical Transformations in Heme Proteins and Metalloporphyrins.
    Chem Rev 2017 Dec 29. Epub 2017 Dec 29.
    Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.
    As a result of the adaptation of life to an aerobic environment, nature has evolved a panoply of metalloproteins for oxidative metabolism and protection against reactive oxygen species. Despite the diverse structures and functions of these proteins, they share common mechanistic grounds. An open-shell transition metal like iron or copper is employed to interact with O2 and its derived intermediates such as hydrogen peroxide to afford a variety of metal-oxygen intermediates. Read More

    Total Synthesis of Aryl C-Glycoside Natural Products: Strategies and Tactics.
    Chem Rev 2017 Dec 27. Epub 2017 Dec 27.
    Department of Chemistry, Tokyo Institute of Technology , 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan.
    The aryl C-glycoside structure is, among the plenty of biologically active natural products, one of the distinct motifs embedded. Because of the potential bioactivity as well as the synthetic challenges, these structures have attracted considerable interest, and extensive research toward the total synthesis has been performed. This Review focuses on the synthetic strategies and tactics employed in the total synthesis of this class of natural products. Read More

    PIWI-Interacting RNA in Drosophila: Biogenesis, Transposon Regulation, and Beyond.
    Chem Rev 2017 Dec 27. Epub 2017 Dec 27.
    Department of Biological Sciences, Graduate School of Science, The University of Tokyo , Tokyo 113-0032, Japan.
    PIWI-interacting RNAs (piRNAs) are germline-enriched small RNAs that control transposons to maintain genome integrity. To achieve this, upon being processed from piRNA precursors, most of which are transcripts of intergenic piRNA clusters, piRNAs bind PIWI proteins, germline-specific Argonaute proteins, to form effector complexes. The mechanism of this piRNA-mediated transposon silencing pathway is fundamentally similar to that of siRNA/miRNA-dependent gene silencing in that a small RNA guides its partner Argonaute protein to target gene transcripts for repression via RNA-RNA base pairing. Read More

    Eight Kinetically Stable but Thermodynamically Activated Molecules that Power Cell Metabolism.
    Chem Rev 2017 Dec 22. Epub 2017 Dec 22.
    Department of Chemical and Biomolecular Engineering and Department of Chemistry and Biochemistry, University of California , Los Angeles, CA 90095-1569, United States.
    Contemporary analyses of cell metabolism have called out three metabolites: ATP, NADH, and acetyl-CoA, as sentinel molecules whose accumulation represent much of the purpose of the catabolic arms of metabolism and then drive many anabolic pathways. Such analyses largely leave out how and why ATP, NADH, and acetyl-CoA (Figure 1 ) at the molecular level play such central roles. Yet, without those insights into why cells accumulate them and how the enabling properties of these key metabolites power much of cell metabolism, the underlying molecular logic remains mysterious. Read More

    Proteolytic Cleavage-Mechanisms, Function, and "Omic" Approaches for a Near-Ubiquitous Posttranslational Modification.
    Chem Rev 2017 Dec 21. Epub 2017 Dec 21.
    Life Sciences Institute, Department of Oral Biological and Medical Sciences, and ‡Department of Biochemistry and Molecular Biology, University of British Columbia , Vancouver, British Columbia V6T 1Z4, Canada.
    Proteases enzymatically hydrolyze peptide bonds in substrate proteins, resulting in a widespread, irreversible posttranslational modification of the protein's structure and biological function. Often regarded as a mere degradative mechanism in destruction of proteins or turnover in maintaining physiological homeostasis, recent research in the field of degradomics has led to the recognition of two main yet unexpected concepts. First, that targeted, limited proteolytic cleavage events by a wide repertoire of proteases are pivotal regulators of most, if not all, physiological and pathological processes. Read More

    Iron and Copper Active Sites in Zeolites and Their Correlation to Metalloenzymes.
    Chem Rev 2017 Dec 19. Epub 2017 Dec 19.
    Department of Chemistry, Stanford University , Stanford, California 94305, United States.
    Metal-exchanged zeolites are a class of heterogeneous catalysts that perform important functions ranging from selective hydrocarbon oxidation to remediation of NOx pollutants. Among these, copper and iron zeolites are remarkably reactive, hydroxylating methane and benzene selectively at low temperature to form methanol and phenol, respectively. In these systems, reactivity occurs at well-defined molecular transition metal active sites, and in this review we discuss recent advances in the spectroscopic characterization of these active sites and their reactive intermediates. Read More

    Beyond Transcription: Roles of Transcription Factors in Pre-mRNA Splicing.
    Chem Rev 2017 Dec 18. Epub 2017 Dec 18.
    Department of Biochemistry and Biophysics, School of Medicine and Dentistry, and ‡Center for RNA Biology, University of Rochester , Rochester, New York 14642, United States.
    Whereas individual steps of protein-coding gene expression in eukaryotes can be studied in isolation in vitro, it has become clear that these steps are intimately connected within cells. Connections not only ensure quality control but also fine-tune the gene expression process, which must adapt to environmental changes while remaining robust. In this review, we systematically present proven and potential mechanisms by which sequence-specific DNA-binding transcription factors can alter gene expression beyond transcription initiation and regulate pre-mRNA splicing, and thereby mRNA isoform production, by (i) influencing transcription elongation rates, (ii) binding to pre-mRNA to recruit splicing factors, and/or (iii) blocking the association of splicing factors with pre-mRNA. Read More

    Application of ω-Transaminases in the Pharmaceutical Industry.
    Chem Rev 2018 Jan 18;118(1):349-367. Epub 2017 Dec 18.
    School of Pharmacy, Queen's University Belfast , Belfast BT9 7BL, N. Ireland, U.K.
    Chiral amines are valuable building blocks for the pharmaceutical industry. ω-TAms have emerged as an exciting option for their synthesis, offering a potential "green alternative" to overcome the drawbacks associated with conventional chemical methods. In this review, we explore the application of ω-TAms for pharmaceutical production. Read More

    Small Bioactive Peptides for Biomaterials Design and Therapeutics.
    Chem Rev 2017 Dec 11;117(24):14015-14041. Epub 2017 Dec 11.
    Department of Chemistry, University of Reading, Whiteknights , Reading RG6 6AD, United Kingdom.
    This review is aimed to provide a concise yet extensive survey of key short bioactive peptide sequences for a range of applications ranging from biomaterials development to peptides with therapeutic uses. The following are considered: cell adhesion motifs, structural peptides, cell-penetrating and tumor-homing peptides, antimicrobial peptides, peptide hormones, growth factors and matrix metalloprotease substrates, neuropeptides, amyloid peptides, antioxidant peptides, peptide affinity tags, anticancer peptides, and others. This review provides a convenient resource, summarizing a broad range of important sequences with great utility as a resource concerning both small peptide drugs and also novel biofunctional peptide-based materials. Read More

    Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment.
    Chem Rev 2017 Dec 8. Epub 2017 Dec 8.
    Institut für Technische und Makromolekulare Chemie, RWTH Aachen University , Worringerweg 2, Aachen 52074, Germany.
    CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. Read More

    Redox-Tag Processes: Intramolecular Electron Transfer and Its Broad Relationship to Redox Reactions in General.
    Chem Rev 2017 Dec 8. Epub 2017 Dec 8.
    Department of Applied Biological Science, Tokyo University of Agriculture and Technology , 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.
    Explosive growth in the use of open shell reactivity, including neutral radicals and radical ions, in the field of synthetic organic chemistry has been observed in the past decade, particularly since the advent of ruthenium complexes in 2008. These complexes generally induce single-electron transfer (SET) processes via visible-light absorption. Additionally, recent significant advancements in organic electrochemistry involving SET processes to provide open shell reactivity offer a complementary method to traditional polarity-driven reactions described by two-electron transfer processes. Read More

    Catalytic Organic Reactions in Water toward Sustainable Society.
    Chem Rev 2017 Dec 8. Epub 2017 Dec 8.
    Department of Chemistry, School of Science, The University of Tokyo , Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
    Traditional organic synthesis relies heavily on organic solvents for a multitude of tasks, including dissolving the components and facilitating chemical reactions, because many reagents and reactive species are incompatible or immiscible with water. Given that they are used in vast quantities as compared to reactants, solvents have been the focus of environmental concerns. Along with reducing the environmental impact of organic synthesis, the use of water as a reaction medium also benefits chemical processes by simplifying operations, allowing mild reaction conditions, and sometimes delivering unforeseen reactivities and selectivities. Read More

    Probing Nanoparticle Plasmons with Electron Energy Loss Spectroscopy.
    Chem Rev 2017 Dec 7. Epub 2017 Dec 7.
    Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States.
    Electron energy loss spectroscopy (EELS) performed in a scanning transmission electron microscope (STEM) has demonstrated unprecedented power in the characterization of surface plasmons. The subangstrom spatial resolution achieved in EELS and its capability of exciting the full set of localized surface plasmon resonance (LSPR) modes supported by a metallic nanostructure makes STEM/EELS an ideal tool in the study of LSPRs. The plasmonic properties characterized using EELS can be associated with geometric or structural features collected simultaneously in a STEM to achieve a deeper understanding of the plasmonic response. Read More

    Dioxygen in Polyoxometalate Mediated Reactions.
    Chem Rev 2017 Dec 1. Epub 2017 Dec 1.
    Department of Organic Chemistry, Weizmann Institute of Science , Rehovot 76100, Israel.
    In this review article, we consider the use of molecular oxygen in reactions mediated by polyoxometalates. Polyoxometalates are anionic metal oxide clusters of a variety of structures that are soluble in liquid phases and therefore amenable to homogeneous catalytic transformations. Often, they are active for electron transfer oxidations of a myriad of substrates and upon reduction can be reoxidized by molecular oxygen. Read More

    Surface-Plasmon-Driven Hot Electron Photochemistry.
    Chem Rev 2017 Nov 30. Epub 2017 Nov 30.
    Department of Chemistry and Center for Catalysis, University of Florida , Gainesville, Florida 32611, United States.
    Visible-light-driven photochemistry has continued to attract heightened interest due to its capacity to efficiently harvest solar energy and its potential to solve the global energy crisis. Plasmonic nanostructures boast broadly tunable optical properties coupled with catalytically active surfaces that offer a unique opportunity for solar photochemistry. Resonant optical excitation of surface plasmons produces energetic hot electrons that can be collected to facilitate chemical reactions. Read More

    From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement.
    Chem Rev 2017 Dec 29;117(24):14201-14243. Epub 2017 Nov 29.
    Instituto de Química Orgánica General, Consejo Superior de Investigaciones Científicas (IQOG-CSIC) , Juan de la Cierva 3, 28006-Madrid, Spain.
    The [2,3]-sigmatropic rearrangement of allylic sulfoxides to allylic sulfenates is a reversible process, generally shifted toward the sulfoxide. In the presence of thiophiles, the sulfenate is trapped, and allylic alcohols are obtained under mild conditions. In most cases, a good transfer of stereochemical information through an ordered transition state is obtained. Read More

    ADP-Ribosylation, a Multifaceted Posttranslational Modification Involved in the Control of Cell Physiology in Health and Disease.
    Chem Rev 2017 Nov 27. Epub 2017 Nov 27.
    Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University , 52057 Aachen, Germany.
    Posttranslational modifications (PTMs) regulate protein functions and interactions. ADP-ribosylation is a PTM, in which ADP-ribosyltransferases use nicotinamide adenine dinucleotide (NAD+) to modify target proteins with ADP-ribose. This modification can occur as mono- or poly-ADP-ribosylation. Read More

    Synthesis and Reactivity of Propargylamines in Organic Chemistry.
    Chem Rev 2017 Dec 22;117(24):14091-14200. Epub 2017 Nov 22.
    School of Cancer and Pharmaceutical Sciences, King's College London , Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
    Propargylamines are a versatile class of compounds which find broad application in many fields of chemistry. This review aims to describe the different strategies developed so far for the synthesis of propargylamines and their derivatives as well as to highlight their reactivity and use as building blocks in the synthesis of chemically relevant organic compounds. In the first part of the review, the different synthetic approaches to synthesize propargylamines, such as A3 couplings and C-H functionalization of alkynes, have been described and organized on the basis of the catalysts employed in the syntheses. Read More

    Crystal Growth with Macromolecular Additives.
    Chem Rev 2017 Dec 22;117(24):14042-14090. Epub 2017 Nov 22.
    Department of Chemistry and Molecular Design Institute, New York University , 100 Washington Square East, New York City, New York 10003, United States.
    Interactions of macromolecules with growing crystalline surfaces play an important role in biomineralization, determine survival of some organisms at low temperatures, and offer a range of potential industrial applications. The current understanding of crystal growth processes in the presence of macromolecules, including peptides and proteins, is reviewed, with a focus on interactions between macromolecules and surfaces of crystalline materials, macromolecule adsorption on different types of crystal surfaces, crystallization kinetics in the presence of macromolecular additives, macromolecule incorporation, and defect generation. Throughout, special attention is paid to the selectivity of macromolecule adsorption on, and incorporation within, crystal surfaces. Read More

    Materials for the Recovery of Uranium from Seawater.
    Chem Rev 2017 Dec 22;117(23):13935-14013. Epub 2017 Nov 22.
    Chemical Sciences Division, Oak Ridge National Laboratory , One Bethel Valley Road, Oak Ridge, Tennessee 37831, United States.
    More than 1000× uranium exists in the oceans than exists in terrestrial ores. With nuclear power generation expected to increase over the coming decades, access to this unconventional reserve is a matter of energy security. With origins in the mid-1950s, materials have been developed for the selective recovery of seawater uranium for more than six decades, with a renewed interest in particular since 2010. Read More

    Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability.
    Chem Rev 2017 Nov 20. Epub 2017 Nov 20.
    Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics , Budapest 1111, Hungary.
    The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). Read More

    Oxygen Activation by Cu LPMOs in Recalcitrant Carbohydrate Polysaccharide Conversion to Monomer Sugars.
    Chem Rev 2017 Nov 20. Epub 2017 Nov 20.
    DuPont Industrial Biosciences , 925 Page Mill Road, Palo Alto, California 94304, United States.
    Natural carbohydrate polymers such as starch, cellulose, and chitin provide renewable alternatives to fossil fuels as a source for fuels and materials. As such, there is considerable interest in their conversion for industrial purposes, which is evidenced by the established and emerging markets for products derived from these natural polymers. In many cases, this is achieved via industrial processes that use enzymes to break down carbohydrates to monomer sugars. Read More

    Super-Resolution Structured Illumination Microscopy.
    Chem Rev 2017 Dec 10;117(23):13890-13908. Epub 2017 Nov 10.
    Biomolecular Photonics, Department of Physics, University of Bielefeld , Universitätsstraße 25, 33615 Bielefeld, Germany.
    Super-resolved structured illumination microscopy (SR-SIM) is among the most rapidly growing fluorescence microscopy techniques that can surpass the optical diffraction limit. The strength of SR-SIM is that it can be readily applied to samples prepared for conventional fluorescence microscopy, requiring no sophisticated sample preparation protocols. As an extension of wide-field fluorescence microscopy, it is inherently capable of multicolor imaging and optical sectioning and, with sufficiently fast implementations, permits live cell imaging. Read More

    Soft X-ray Absorption Spectroscopy of Liquids and Solutions.
    Chem Rev 2017 Dec 10;117(23):13909-13934. Epub 2017 Nov 10.
    Department of Chemistry, University of California , Berkeley, California 94720, United States.
    X-ray absorption spectroscopy (XAS) is an electronic absorption technique for which the initial state is a deeply buried core level. The photon energies corresponding to such transitions are governed primarily by the binding energies of the initial state. Because the binding energies of core electrons vary significantly among atomic species, this makes XAS an element-selective spectroscopy. Read More

    O2 Activation by Metal Surfaces: Implications for Bonding and Reactivity on Heterogeneous Catalysts.
    Chem Rev 2017 Nov 8. Epub 2017 Nov 8.
    Department of Chemistry and Chemical Biology, Harvard University , 12 Oxford St, Cambridge, Massachusetts 02138, United States.
    The activation of O2 on metal surfaces is a critical process for heterogeneous catalysis and materials oxidation. Fundamental studies of well-defined metal surfaces using a variety of techniques have given crucial insight into the mechanisms, energetics, and dynamics of O2 adsorption and dissociation. Here, trends in the activation of O2 on transition metal surfaces are discussed, and various O2 adsorption states are described in terms of both electronic structure and geometry. Read More

    Chemical Biology of H2S Signaling through Persulfidation.
    Chem Rev 2017 Nov 7. Epub 2017 Nov 7.
    Department of Biological Chemistry, University of Michigan Medical School , Ann Arbor, Michigan 48109-0600, United States.
    Signaling by H2S is proposed to occur via persulfidation, a posttranslational modification of cysteine residues (RSH) to persulfides (RSSH). Persulfidation provides a framework for understanding the physiological and pharmacological effects of H2S. Due to the inherent instability of persulfides, their chemistry is understudied. Read More

    Aerobic Oxidations of Light Alkanes over Solid Metal Oxide Catalysts.
    Chem Rev 2017 Nov 7. Epub 2017 Nov 7.
    Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
    Heterogeneous metal oxide catalysts are widely studied for the aerobic oxidations of C1-C4 alkanes to form olefins and oxygenates. In this review, we outline the properties of supported metal oxides, mixed-metal oxides, and zeolites and detail their most common applications as catalysts for partial oxidations of light alkanes. By doing this we establish similarities between different classes of metal oxides and identify common themes in reaction mechanisms and research strategies for catalyst improvement. Read More

    Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion.
    Chem Rev 2017 Dec 1;117(23):13810-13889. Epub 2017 Nov 1.
    Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University , Beijing 100871, China.
    Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals in cross-coupling area is expanding the scope of the coupling partners. In the past decade, diazo compounds (or their precursors N-tosylhydrazones) have emerged as nucleophilic cross-coupling partners in C-C single bond or C═C double bond formations in transition-metal-catalyzed reactions. Read More

    Theory and Simulation of the Ultrafast Double-Bond Isomerization of Biological Chromophores.
    Chem Rev 2017 Nov 30;117(22):13502-13565. Epub 2017 Oct 30.
    Chemistry Department, Bowling Green State University , Overman Hall, Bowling Green, Ohio 43403, United States.
    Ultrafast processes in light-absorbing proteins have been implicated in the primary step in the light-to-energy conversion and the initialization of photoresponsive biological functions. Theory and computations have played an instrumental role in understanding the molecular mechanism of such processes, as they provide a molecular-level insight of structural and electronic changes at ultrafast time scales that often are very difficult or impossible to obtain from experiments alone. Among theoretical strategies, the application of hybrid quantum mechanics and molecular mechanics (QM/MM) models is an important approach that has reached an evident degree of maturity, resulting in several important contributions to the field. Read More

    Electrogenerated Cationic Reactive Intermediates: The Pool Method and Further Advances.
    Chem Rev 2017 Oct 27. Epub 2017 Oct 27.
    Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan.
    Electrochemistry serves as a powerful method for generating reactive intermediates, such as organic cations. In general, there are two ways to use reactive intermediates for chemical reactions: (1) generation in the presence of a reaction partner and (2) generation in the absence of a reaction partner with accumulation in solution as a "pool" followed by reaction with a subsequently added reaction partner. The former approach is more popular because reactive intermediates are usually short-lived transient species, but the latter method is more flexible and versatile. Read More

    Photochemistry and Photophysics in Silica-Based Materials: Ultrafast and Single Molecule Spectroscopy Observation.
    Chem Rev 2017 Nov 25;117(22):13639-13720. Epub 2017 Oct 25.
    Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha , Avenida Carlos III, S.N., 45071 Toledo, Spain.
    Silica-based materials (SBMs) are widely used in catalysis, photonics, and drug delivery. Their pores and cavities act as hosts of diverse guests ranging from classical dyes to drugs and quantum dots, allowing changes in the photochemical behavior of the confined guests. The heterogeneity of the guest populations as well as the confinement provided by these hosts affect the behavior of the formed hybrid materials. Read More

    Group 6 Dihapto-Coordinate Dearomatization Agents for Organic Synthesis.
    Chem Rev 2017 Nov 24;117(22):13721-13755. Epub 2017 Oct 24.
    Department of Chemistry, University of Virginia , Charlottesville, Virginia 22904, United States.
    This review covers publications ranging from 2005 to 2017 concerning the organic reactions of aromatic ligands η2-coordinated to tungsten or molybdenum and the use of these reactions in the synthesis of novel organic substances. An emphasis is placed on C-C bond-forming reactions using conventional building blocks of organic synthesis such as acetals, enolates, Michael acceptors, acylating reagents, and activated aromatics. Substrates activated by the metal include arenes, pyridines, pyrroles, pyrimidines, furans, and thiophenes. Read More

    Catalysis as an Enabling Science for Sustainable Polymers.
    Chem Rev 2017 Oct 19. Epub 2017 Oct 19.
    Department of Chemistry, Stanford University , Stanford, California 94305-5080, United States.
    The replacement of current petroleum-based plastics with sustainable alternatives is a crucial but formidable challenge for the modern society. Catalysis presents an enabling tool to facilitate the development of sustainable polymers. This review provides a system-level analysis of sustainable polymers and outlines key criteria with respect to the feedstocks the polymers are derived from, the manner in which the polymers are generated, and the end-of-use options. Read More

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