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Chemical Reviews

Shaojian Tang, Xia Zhang, Jiayue Sun, Dawen Niu, Jason J Chruma
This review covers the use of 2-azaallyl anions, 2-azaallyl cations, and 2-azaallyl radicals in organic synthesis up through June 2018. Particular attention is paid to both foundational studies and recent advances over the past decade involving semistabilized and nonstabilized 2-azaallyl anions as key intermediates in various carbon-carbon and carbon-heteroatom bond-forming processes. Both transition-metal-catalyzed and transition-metal-free transformations are covered. Azomethine ylides, which have received significant attention elsewhere, are discussed briefly with the primary focus on critical comparisons with 2-azaallyl anions in regard to generation and use...
October 10, 2018: Chemical Reviews
Eszter Boros, Alan B Packard
Nuclear medicine is composed of two complementary areas, imaging and therapy. Positron emission tomography (PET) and single-photon imaging, including single-photon emission computed tomography (SPECT), comprise the imaging component of nuclear medicine. These areas are distinct in that they exploit different nuclear decay processes and also different imaging technologies. In PET, images are created from the 511 keV photons produced when the positron emitted by a radionuclide encounters an electron and is annihilated...
October 9, 2018: Chemical Reviews
Xiaohui Wang, Xiaoyong Wang, Suxing Jin, Nafees Muhammad, Zijian Guo
The success of platinum-based anticancer agents has motivated the exploration of novel metal-based drugs for several decades, whereas problems such as drug-resistance and systemic toxicity hampered their clinical applications and efficacy. Stimuli-responsiveness of some metal complexes offers a good opportunity for designing site-specific prodrugs to maximize the therapeutic efficacy and minimize the side effect of metallodrugs. This review presents a comprehensive and up-to-date overview on the therapeutic stimuli-responsive metallodrugs that have appeared in the past two decades, where stimuli such as redox, pH, enzyme, light, temperature, and so forth were involved...
October 9, 2018: Chemical Reviews
Ryan R Langeslay, David M Kaphan, Christopher L Marshall, Peter C Stair, Alfred P Sattelberger, Massimiliano Delferro
The chemistry of vanadium has seen remarkable activity in the past 50 years. In the present review, reactions catalyzed by homogeneous and supported vanadium complexes from 2008 to 2018 are summarized and discussed. Particular attention is given to mechanistic and kinetics studies of vanadium-catalyzed reactions including oxidations of alkanes, alkenes, arenes, alcohols, aldehydes, ketones, and sulfur species, as well as oxidative C-C and C-O bond cleavage, carbon-carbon bond formation, deoxydehydration, haloperoxidase, cyanation, hydrogenation, dehydrogenation, ring-opening metathesis polymerization, and oxo/imido heterometathesis...
October 8, 2018: Chemical Reviews
Susan Monro, Katsuya L Colón, Huimin Yin, John Roque, Prathyusha Konda, Shashi Gujar, Randolph P Thummel, Lothar Lilge, Colin G Cameron, Sherri A McFarland
Transition metal complexes are of increasing interest as photosensitizers in photodynamic therapy (PDT) and, more recently, for photochemotherapy (PCT). In recent years, Ru(II) polypyridyl complexes have emerged as promising systems for both PDT and PCT. Their rich photochemical and photophysical properties derive from a variety of excited-state electronic configurations accessible with visible and near-infrared light, and these properties can be exploited for both energy- and electron-transfer processes that can yield highly potent oxygen-dependent and/or oxygen-independent photobiological activity...
October 8, 2018: Chemical Reviews
Velencia J Witherspoon, Jun Xu, Jeffrey A Reimer
Solid-state nuclear magnetic resonance (SSNMR) methods have been routinely used for the characterization of both the structure and the dynamics of metal organic frameworks (MOFs), a collection of porous media investigated for potential applications in carbon capture technologies, selective separation of small molecules, and catalysis. (1) The use and development of SSNMR techniques that enable the nondestructive characterization of the adsorbed behavior have become essential steps in bettering our understanding of MOFs and are often complementary to traditional methods of structural characterization...
October 5, 2018: Chemical Reviews
Corey J Wilson, Andreas S Bommarius, Julie A Champion, Yury O Chernoff, David G Lynn, Anant K Paravastu, Chen Liang, Ming-Chien Hsieh, Jennifer M Heemstra
Biomolecular assembly is a key driving force in nearly all life processes, providing structure, information storage, and communication within cells and at the whole organism level. These assembly processes rely on precise interactions between functional groups on nucleic acids, proteins, carbohydrates, and small molecules, and can be fine-tuned to span a range of time, length, and complexity scales. Recognizing the power of these motifs, researchers have sought to emulate and engineer biomolecular assemblies in the laboratory, with goals ranging from modulating cellular function to the creation of new polymeric materials...
October 3, 2018: Chemical Reviews
Andreas Schneemann, James L White, ShinYoung Kang, Sohee Jeong, Liwen F Wan, Eun Seon Cho, Tae Wook Heo, David Prendergast, Jeffrey J Urban, Brandon C Wood, Mark D Allendorf, Vitalie Stavila
Knowledge and foundational understanding of phenomena associated with the behavior of materials at the nanoscale is one of the key scientific challenges toward a sustainable energy future. Size reduction from bulk to the nanoscale leads to a variety of exciting and anomalous phenomena due to enhanced surface-to-volume ratio, reduced transport length, and tunable nanointerfaces. Nanostructured metal hydrides are an important class of materials with significant potential for energy storage applications. Hydrogen storage in nanoscale metal hydrides has been recognized as a potentially transformative technology, and the field is now growing steadily due to the ability to tune the material properties more independently and drastically compared to those of their bulk counterparts...
October 2, 2018: Chemical Reviews
Valerie Vaissier Welborn, Teresa Head-Gordon
We review the standard model for de novo computational design of enzymes, which primarily focuses on the development of an active-site geometry, composed of protein functional groups in orientations optimized to stabilize the transition state, for a novel chemical reaction not found in nature. Its emphasis is placed on the structure and energetics of the active site embedded in an accommodating protein that serves as a physical support that shields the reaction chemistry from solvent, which is typically improved upon by laboratory-directed evolution...
October 2, 2018: Chemical Reviews
Hongchao Guo, Yi Chiao Fan, Zhanhu Sun, Yang Wu, Ohyun Kwon
The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon-carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita-Baylis-Hillman (MBH) alcohol derivatives (MBHADs; section 5)...
September 27, 2018: Chemical Reviews
Wanxiang Zhao, Jianwei Sun
Triflimide (HNTf2 ) is a commercially available and highly versatile super Brønsted acid. Owing to its strong acidity as well as good compatibility with organic solvents, it has been widely employed as an exceptional catalyst, promoter, or additive in a wide range of organic reactions. On many occasions, triflimide has been demonstrated to outperform triflic acid (TfOH). The uniquely outstanding performance of triflimide also benefits from the low nucleophilicity and noncoordinating property of its conjugate base (Tf2 N- )...
September 25, 2018: Chemical Reviews
Nongnoot Wongkaew, Marcel Simsek, Christian Griesche, Antje J Baeumner
Electrochemical biosensors and associated lab-on-a-chip devices are the analytical system of choice when rapid and on-site results are needed in medical diagnostics and food safety, for environmental protection, process control, wastewater treatment, and life sciences discovery research among many others. A premier example is the glucose sensor used by diabetic patients. Current research focuses on developing sensors for specific analytes in these application fields and addresses challenges that need to be solved before viable commercial products can be designed...
September 24, 2018: Chemical Reviews
J R Mejía-Salazar, Osvaldo N Oliveira
Plasmonic biosensing has been used for fast, real-time, and label-free probing of biologically relevant analytes, where the main challenges are to detect small molecules at ultralow concentrations and produce compact devices for point-of-care (PoC) analysis. This review discusses the most recent, or even emerging, trends in plasmonic biosensing, with novel platforms which exploit unique physicochemical properties and versatility of new materials. In addition to the well-established use of localized surface plasmon resonance (LSPR), three major areas have been identified in these new trends: chiral plasmonics, magnetoplasmonics, and quantum plasmonics...
September 24, 2018: Chemical Reviews
Joseph J BelBruno
Molecularly imprinted polymers are synthetic receptors for a targeted molecule. As such, they are analogues of the natural antibody-antigen systems. In this review, after a recounting of the early history of the general field, we specifically focus on the application of these polymers as sensors. In these applications, the polymers are paired with a reporting system, which may be electrical, electrochemical, optical, or gravimetric. The presence of the targeted molecule effects a change in the reporting agent, and a calibrated quantity of the target is recorded...
September 24, 2018: Chemical Reviews
Andrey A Tregubov, Petr I Nikitin, Maxim P Nikitin
Accurate and precise drug delivery is the key to successful therapy. Monoclonal antibodies, which can transport therapeutic payload to cells expressing specific markers, have paved the way for targeted drug delivery and currently show tremendous clinical success. However, in those abundant cases, when a disease cannot be characterized by a single specific marker, more sophisticated drug delivery systems are required. To enhance targeting accuracy, diverse smart materials have been proposed that can also react to stimuli like variations of pH, temperature, magnetic field, etc...
September 20, 2018: Chemical Reviews
Vera Schroeder, Suchol Savagatrup, Maggie He, Sibo Lin, Timothy M Swager
Carbon nanotubes (CNTs) promise to advance a number of real-world technologies. Of these applications, they are particularly attractive for uses in chemical sensors for environmental and health monitoring. However, chemical sensors based on CNTs are often lacking in selectivity, and the elucidation of their sensing mechanisms remains challenging. This review is a comprehensive description of the parameters that give rise to the sensing capabilities of CNT-based sensors and the application of CNT-based devices in chemical sensing...
September 18, 2018: Chemical Reviews
Zheng Li, Jon R Askim, Kenneth S Suslick
A comprehensive review on the development and state of the art of colorimetric and fluorometric sensor arrays is presented. Chemical sensing aims to detect subtle changes in the chemical environment by transforming relevant chemical or physical properties of molecular or ionic species (i.e., analytes) into an analytically useful output. Optical arrays based on chemoresponsive colorants (dyes and nanoporous pigments) probe the chemical reactivity of analytes, rather than their physical properties (e.g., mass)...
September 12, 2018: Chemical Reviews
Allie Y Chen, Rebecca N Adamek, Benjamin L Dick, Cy V Credille, Christine N Morrison, Seth M Cohen
Metalloenzymes are central to a wide range of essential biological activities, including nucleic acid modification, protein degradation, and many others. The role of metalloenzymes in these processes also makes them central for the progression of many diseases and, as such, makes metalloenzymes attractive targets for therapeutic intervention. Increasing awareness of the role metalloenzymes play in disease and their importance as a class of targets has amplified interest in the development of new strategies to develop inhibitors and ultimately useful drugs...
September 7, 2018: Chemical Reviews
Limor Cohen, David R Walt
Proteins are involved in many biological processes. Misfolded, truncated, or mutated proteins as well as over- or underexpressed proteins have been implicated in many diseases. Therefore, detection and quantification of proteins is extremely important. Conventional techniques such as the enzyme-linked immunosorbent assay, Western Blot, and mass spectrometry have enabled discovery and study of proteins in biological samples. However, many important proteins are present at low concentrations, rendering them undetectable using conventional techniques...
August 28, 2018: Chemical Reviews
Masha G Savelieff, Geewoo Nam, Juhye Kang, Hyuck Jin Lee, Misun Lee, Mi Hee Lim
Neurodegenerative diseases pose a substantial socioeconomic burden on society. Unfortunately, the aging world population and lack of effective cures foreshadow a negative outlook. Although a large amount of research has been dedicated to elucidating the pathologies of neurodegenerative diseases, their principal causes remain elusive. Metal ion dyshomeostasis, proteopathy, oxidative stress, and neurotransmitter deficiencies are pathological features shared across multiple neurodegenerative disorders. In addition, these factors are proposed to be interrelated upon disease progression...
August 10, 2018: Chemical Reviews
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