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Journal of the American Chemical Society

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https://www.readbyqxmd.com/read/30456949/revisiting-conversion-reaction-mechanisms-in-lithium-batteries-lithiation-driven-topotactic-transformation-in-fef-2
#1
Khim Karki, Lijun Wu, Ying Ma, Mark J Armstrong, Justin D Holmes, Stephen H Garofalini, Yimei Zhu, Eric A Stach, Feng Wang
Intercalation-type electrodes have now been commonly employed in today's batteries due to their capability of storing and releasing lithium reversibly via topotactic transformation, conducive to small structural change, but they have limited interstitial sites to hold Li. In contrast, conversion electrodes feature high Li-storage capacity, but often undergo large structural change during (de)lithiation, resulting in cycling instability. One exception is iron fluoride (FeF2 ), a conversion-type cathode that exhibits both high capacity and high cycling stability...
November 20, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30453734/atomic-scale-explanation-of-o-2-activation-at-the-au-tio-2-interface
#2
Niklas Siemer, Alexander Lüken, Michal Zalibera, Johannes Frenzel, Daniel Muñoz-Santiburcio, Anton Savitsky, Wolfgang Lubitz, Martin Muhler, Dominik Marx, Jennifer Strunk
By a combination of EPR spectroscopy, finite-temperature ab initio simulations, and electronic structure analyses, the activation of molecular dioxygen at the interface of gold nanoparticles and titania in Au/TiO2 catalysts is explained at the atomic scale by tracing processes down to the molecular orbital picture. Direct evidence is provided that excess electrons in TiO2 , for example created by photoexcitation of the semiconductor, migrate to the gold particles and from there to oxygen molecules adsorbed at gold/titania perimeter sites...
November 20, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30453733/synthesis-and-characterization-of-non-ipr-actinide-endohedral-metallofullerenes-u-c1-17418-c76-u-c1-28324-c80-and-th-c1-28324-c80-low-symmetry-cage-selection-directed-by-a-tetravalent-ion
#3
Wenting Cai, Laura Abella, Jiaxin Zhuang, Xingxing Zhang, Lai Feng, Yaofeng Wang, Roser Morales-Martínez, Ronda Esper, Mauro Boero, Alejandro Metta-Magaña, Antonio Rodríguez-Fortea, Josep M Poblet, Luis Echegoyen, Ning Chen
For the first time, actinide endohedral metallofullerenes (EMFs) with non-IPR carbon cages, U@C80, Th@C80 and U@C76, have been successfully synthesized and fully characterized by mass spectrometry, single crystal X-ray diffractometry, UV-vis-NIR, Raman and cyclic voltammetry. Crystallographic analysis revealed that the U@C80 and Th@C80 share the same non-IPR cage of C1(28324)-C80, and U@C76 was assigned to non-IPR U@C1(17418)-C76. All of these cages are chiral and have never been reported before. Further structural analyses show that enantiomers of C1(17418)-C76 and C1(28324)-C80 share a significant continuous portion of the cage and are topologically connected by only two C2 insertions...
November 20, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30407807/turning-au-nanoclusters-catalytically-active-for-visible-light-driven-co-2-reduction-through-bridging-ligands
#4
Xiaofeng Cui, Jin Wang, Bing Liu, Shan Ling, Ran Long, Yujie Xiong
Development of visible-light photocatalytic materials is an ultimate goal for solar-driven CO2 conversion. Au nanoclusters (NCs) may potentially serve as components for harvesting visible light but can hardly perform solar-driven CO2 reduction due to the lack of catalytic sites. Herein, we report an effective strategy for turning Au nanoclusters catalytically active for visible-light CO2 reduction, in which metal cations (Fe2+ , Co2+ , Ni2+ , and Cu2+ ) are grafted to the Au NCs using l-cysteine as a bridging ligand...
November 20, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30403846/heterostructure-promoted-oxygen-electrocatalysis-enables-rechargeable-zinc-air-battery-with-neutral-aqueous-electrolyte
#5
Li An, Zhiyong Zhang, Jianrui Feng, Fan Lv, Yuxuan Li, Rui Wang, Min Lu, Ram B Gupta, Pinxian Xi, Sen Zhang
Neutral aqueous zinc-air batteries (ZABs) are an emerging type of energy devices with substantially elongated lifetime and improved recyclability compared to conventional alkaline ZABs. However, their development is impeded by the lack of robust bifunctional catalyst at the air-electrode for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). Here, we report the controlled synthesis of NiFe2 O4 /FeNi2 S4 heterostructured nanosheets (HNSs) that are highly efficient in catalyzing OER and ORR, therefore enabling neutral rechargeable ZABs...
November 20, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452863/photoreduction-of-co2-with-a-formate-dehydrogenase-driven-by-photosystem-ii-using-a-semi-artificial-z-scheme-architecture
#6
Katarzyna Sokol, William E Robinson, Ana Oliveira, Julien Warnan, Marc M Nowaczyk, Adrian Ruff, Inês Antunes Cardoso Pereira, Erwin Reisner
Solar-driven coupling of water oxidation with CO2 reduction sustains life on our planet and is of high priority to contempo-rary energy research. Here, we report a photoelectrochemical tandem device, which performs photocatalytic CO2 reduction to formate. We employ a semi-artificial design, which wires a W-dependent formate dehydrogenase (FDH) cathode to a pho-toanode containing the photosynthetic water oxidation en-zyme, photosystem II, via a synthetic dye with complementary light absorption. From a biological perspective, the system achieves a metabolically-inaccessible pathway of light-driven CO2 fixation to formate...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452862/optically-active-inverse-opal-photonic-crystals
#7
Ke Hou, Wajid Ali, Jiawei Lv, Jun Guo, Lin Shi, Bing Han, Xiaoli Wang, Zhiyong Tang
Chiral photonic crystals have been a widely investigated topic in chemistry, physics and biology. Till now, the researches about chiral photonic crystals are conducted on the objects of helical structures, while the chiral photonic crystals made of periodic chiral media remain unexplored experimentally. In this work, we have successfully constructed three-dimensional chiral polymer inverse opal photonic crystals (3D CPIOPCs) by a template-based method. Impressively, the 3D CPIOPCs exhibit emerging circular dichroism responses near the photonic band gaps...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452259/a-3-dimensional-fully-conjugated-carbaporphyrin-cage
#8
Xian-Sheng Ke, Taeyeon Kim, Qing He, Vincent M Lynch, Dongho Kim, Jonathan L Sessler
A fully conjugated 3-dimensional (3D) expanded carboporphy-rin (2) was prepared in a one-pot procedure that involves a [2+4] condensation reaction between a dibenzo[g,p]chrysene-bearing tetrapyrrole precursor (1) and pentafluorobenzalde-hyde, followed by oxidation. Single crystal X-ray diffraction analysis revealed that 2 possesses a cage-like structure consist-ing of four dipyrromethenes and two bridging diben-zo[g,p]chrysene units. As prepared, 2 is nonaromatic as inferred from UV-vis-NIR and 1H NMR spectroscopy and a near-zero (-1...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452256/multi-triggered-supramolecular-dna-bipyridinium-dithienylethene-hydrogels-driven-by-light-redox-and-chemical-stimuli-for-shape-memory-and-self-healing-applications
#9
Ziyuan Li, Gilad Davidson-Rozenfeld, Margarita Vázquez-González, Michael Fadeev, Junji Zhang, He Tian, Itamar Willner
Multi-triggered DNA/bipyridinium-dithienylethene (DTE) hybrid carboxymethyl cellulose (CMC) based hydrogels are introduced. DTE exhibits cyclic and reversible photoisomerization properties, switching between the closed state (DTEc ), the electron acceptor, and the open isomer (DTEo ) that lacks electron acceptor properties. One system includes the syn-thesis of CMC chains modified with electron donor dopamine sites and self-complementary nucleic acid tethers. In the presence of DTEc and the CMC scaffold, a stiff hydrogel, cooperatively stabilized by dopamine/DTEc donor-acceptor in-teractions and by the duplex nucleic acids is formed...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452254/scalable-fiber-like-micelles-and-block-co-micelles-by-polymerization-induced-crystallization-driven-self-assembly
#10
Alex M Oliver, Jessica Gwyther, Charlotte E Boott, Sean Davis, Samuel Pearce, Ian Manners
Self-assembled 1D block copolymer nanoparticles (micelles) are of interest for a range of applications. However, mor-phologically pure samples are often challenging to access, and precise dimensional control is not possible. Moreover, the development of synthetic protocols that operate on a commercially viable scale has been a major challenge. Herein, we describe the preparation 1D fiber-like micelles with crystalline cores at high concentrations by a one-pot process termed polymerization-induced crystallization-driven self-assembly (PI-CDSA)...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452253/4-6-o-pyruvyl-ketal-modified-n-acetyl-mannosamine-of-the-secondary-cell-polysaccharide-of-bacillus-anthracis-is-the-anchoring-residue-for-its-surface-layer-proteins
#11
Robert N Chapman, Lin Liu, Geert-Jan Boons
The secondary cell wall polysaccharide (SCWP) of Bacillus anthracis plays a key role in the organization of the cell envelope of vegetative cells and is intimately involved in host-guest interactions. Genetic studies have indicated that it anchors S-layer and S-layer associated proteins, which are involved in multiple vital biological functions, to the cell surface of B. anthracis. Phenotypic observations indicate that specific functional groups of the terminal unit of SCWP, including 4,6-O-pyruvyl ketal and acetyl esters, are important for binding of these proteins...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452251/self-assembly-of-goldberg-polyhedra-from-a-concave-wv5o11-rco2-5-so4-3-building-block-with-5-fold-symmetry
#12
Yuteng Zhang, Hongmei Gan, Chao Qin, Xinlong Wang, Zhongmin Su, Michael J Zaworotko
Nanoscale regular polyhedra with icosahedral symmetry exist naturally as exemplified by virus capsids and fullerenes. Nevertheless, their generation by supramolecular chemistry through the linking of 5-fold symmetry vertices remains unmet because of the absence of 5-fold symmetry building blocks with the requisite geometric features. This situation contrasts with that of tetrahedral and octahedral symmetry metal-organic polyhedra (MOPs), for which appropriate triangular and square molecular building blocks (MBBs) that can serve as vertices or faces are readily available...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452250/lead-free-direct-bandgap-double-perovskite-nanocrystals-with-bright-dual-color-emission
#13
Bin Yang, Xin Mao, Feng Hong, Weiwei Meng, Yuxuan Tang, Xusheng Xia, Songqiu Yang, Weiqiao Deng, Keli Han
Lead-free double perovskite nanocrystals (NCs), i.e. Cs2AgInxBi1xCl6 (x = 0, 0.25, 0.5 0.75 and 0.9), that can be tuned from the indirect bandgap (x = 0, 0.25 and 0.5) to the direct bandgap (x = 0.75 and 0.9) are designed. Direct-bandgap NCs exhibit 3 times greater absorption cross-section, lower sub-bandgap trap states, and >5 times photoluminescence quantum efficiency (PLQE) compared with those observed for indirect bandgap NCs (Cs2AgBiCl6). A PLQE of 36.6% for direct bandgap NCs is comparable to those observed for lead-perovskite NCs in the violet region...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452248/site-selective-nucleation-and-size-control-of-gold-nanoparticle-photothermal-antennae-on-the-pore-structures-of-a-virus
#14
Candace E Benjamin, Zhuo Chen, Peiyuan Kang, Blake A Wilson, Na Li, Steven O Nielsen, Zhenpeng Qin, Jeremiah J Gassensmith
In this article, we show that the surface of the bacteriophage Qβ is equipped with natural ligands for the synthesis of small gold nanoparticles. By exploiting disulfides in the protein secondary structure and the geometry formed from the capsid quaternary structure, we find we can produce regularly arrayed patterns of ~6 nm gold nanoparticles across the surface of the virus-like particle. Experimental and computational analysis provide insight into the formation and stabil-ity of this composite. We further show that the entrapped genetic material can hold upwards of 500 molecules of the an-ti-cancer drug Doxorubicin without leaking and without interfering with the synthesis of the gold nanoparticles...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452246/instructed-assembly-of-peptides-for-intracellular-enzyme-sequestration
#15
Zhaoqianqi Feng, Huaimin Wang, Bing Xu
Liquid-like droplets of biomacromolecules are emerging as a fundamental mechanism of cellular signaling, but designing synthetic mimics to form such membraneless organelles remains unexplored. Here we report the use of supramolecular assemblies of small peptides, as a mimic of biomacromolecular condensates, for intracellular sequestration of enzymes on endoplasmic reticulum (ER). Specifically, integrating a short peptide with naproxen (a nonsteroidal anti-inflammatory drug (NSAID) and a ligand of cyclooxy-genase-2 (COX-2)) generates an enzymatic substrate that acts as a precursor for instructed-assembly...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30452238/reprogramming-exosomes-as-nanoscale-controllers-of-cellular-immunity
#16
Qinqin Cheng, Xiaojing Shi, Menglu Han, Goar Smbatyan, Heinz-Josef Lenz, Yong Zhang
Exosomes are naturally occurring membranous vesicles secreted by various types of cells. Given their unique and important biological and pharmacological properties, exosomes have been emerging as a promising form of nanomedicine acting via efficient delivery of endogenous and exogenous therapeutics. Here we explore a new concept of utilizing endogenously derived exosomes as artificial controllers of cellular immunity to redirect and activate cytotoxic T cells toward cancer cells for killing. This was achieved through genetically displaying two distinct types of antibodies on exosomal surface...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30451496/enantioselective-coupling-of-dienes-and-phosphine-oxides
#17
Shao-Zhen Nie, Ryan T Davison, Vy M Dong
We report a Pd-catalyzed intermolecular hydrophosphinylation of 1,3-dienes to afford chiral allylic phosphine oxides. Commodity dienes and air stable phosphine oxides couple to generate organophosphorus building blocks with high enantio- and regiocontrol. This method constitutes the first asymmetric hydrophosphinylation of dienes.
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30449094/tailored-phase-conversion-under-conjugated-polymer-enables-thermally-stable-perovskite-solar-cells-with-efficiency-exceeding-21
#18
Lei Meng, Chenkai Sun, Rui Wang, Wenchao Huang, Zipeng Zhao, Pengyu Sun, Tianyi Huang, Jingjing Xue, Jin-Wook Lee, Chenhui Zhu, Yu Huang, Yongfang Li, Yang Yang
The precise control of stoichiometric balance and ionic defects on the surface of solution-processed perovskite is critical to the performance and stability of perovskite solar cells (pero-SCs). Here, we introduce a low-cost and stable conjugated donor polymer (PTQ10) as interfacial layer in the planar n-i-p structured pero-SCs. The polymer was applied to the perovskite intermediate phase before the thermal annealing. This treatment significantly reduced the loss of surface organic cation during thermal annealing...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30449091/spiroborate-based-double-stranded-helicates-meso-to-racemo-isomerization-and-ion-triggered-spring-like-motion-of-the-racemo-helicate
#19
Naoki Ousaka, Kaori Shimizu, Yoshimasa Suzuki, Takuya Iwata, Manabu Itakura, Daisuke Taura, Hiroki Iida, Yoshio Furusho, Tadashi Mori, Eiji Yashima
A one-handed double-stranded spiroborate helicate exhibits a unique reversible extension-contraction motion coupled with a twisting motion in one direction triggered by binding and release of a Na+ ion while retaining its handedness. Here we report that an extended meso-helicate was also produced together with the racemo-helicate, and the meso-helicate was readily con-verted to the racemo-helicate assisted by a Na+ ion as a template in the presence of water. The thermodynamic analyses of the ion-triggered spring-like motion of the racemo-helicate using a series of monovalent cations with different sizes revealed that the association constants of the extended racemo-helicate decreased in the following order: Li+ > Na+ > NH4+ > Ag+ ≥ K+ > Cs+ > Rb+, which roughly agrees with the reverse order of their ionic radii except for the NH4+ ion due to the more elongated contracted helicates when complexed with larger cations as supported by the crystal and DFT calculated structures...
November 19, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30449090/an-intrinsically-disordered-peptide-peptide-stapler-for-highly-efficient-protein-ligation-both-in-vivo-and-in-vitro
#20
Xia-Ling Wu, Yajie Liu, Dong Liu, Fei Sun, Wen-Bin Zhang
Herein, we report an intrinsically disordered protein SpyStapler that can catalyze the isopeptide bond formation between two pep-tide tags, i.e. SpyTag and BDTag, both in vitro and in vivo. SpyStapler and BDTag are developed by splitting SpyCatcher-the cog-nate protein partner of SpyTag-at the more solvent exposed second loop region. Regardless of their locations in protein constructs, SpyStapler enables efficient covalent coupling of SpyTag and BDTag under a variety of mild conditions in vitro (yield ~80%)...
November 19, 2018: Journal of the American Chemical Society
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