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Chemistry, An Asian Journal

Zi Liang Wu, Chen Yu Li, Xing Peng Hao, Qiang Zheng
Programmed deformations are widespread in nature, providing elegant paradigms to design self-morphing materials with promising applications in biomedical devices, flexible electronics, soft robotics, etc. In this emerging field, hydrogels are an ideal material to investigate the deformation principle and the structure-deformation relationship. One crucial step is to construct heterogeneous structures in a facile yet effective way. In this paper, we provide a focus review on different deformation modes and corresponding structural features of hydrogels...
September 21, 2018: Chemistry, An Asian Journal
Yijin Shu, Ting Chen, Hang Cheong Chan, Lifang Xie, Qingsheng Gao
Hydrogenation of α,β-unsaturated aldehydes to value-added unsaturated alcohols suffers a huge challenge in chemoselectivity. Herein, surface decoration by FeOx is introduced to remarkably improve the selectivity of cinnamyl alcohol (COL) in cinnamaldehyde (CAL) hydrogenation on Pt/MoO3-y. The enhanced acidity on Pt-FeOx interfaces is beneficial for the chemisorption and activation of C=O bonds, promoting selective hydrogenation. The optimal catalysts with defined FeOx decoration afford efficient and chemoselective CAL hydrogenation (sel...
September 19, 2018: Chemistry, An Asian Journal
Jingjing Wu, Xin Liu, Yulei Hao, Hongjiang Chen, Peifeng Su, Wei Wu, Jun Zhu
Aromaticity is one of the most fundamental and fascinating chemical topics, attracting both experimental and theoretical chemists due to its many manifestations. Both σ- and π-aromaticity can be classified, depending on the character of the cyclic electron delocalization. In general, σ-aromaticity stabilizes fully saturated rings with σ-electron delocalization whereas the traditional π-aromaticity describes the π-conjugation in fully unsaturated rings. Here we demonstrate a strong correlation between nucleus-independent chemical shift (NICS) values and extra cyclic resonance energies (ECREs) used to evaluate the σ-aromaticity in an unsaturated three-membered ring (3MR) of cyclopropene, which were computed by molecular orbital (MO) theory and valence bond (VB) theory, respectively...
September 19, 2018: Chemistry, An Asian Journal
Sudhakar Ganta, Dillip Kumar Chand
Supramolecular gels prepared from low molecular weight gelators are hugely explored. However, exploitation of discrete or polymeric metal complexes as gelators is a relatively recent trend. Synthesis of self-assembled coordination complexes from palladium(II) and selected ligands is well established but the potential of such complexes as gelators is a less explored treasure. This review focuses on the gelation abilities of some self-assembled palladium(II) complexes and ensuing unique properties. First part of the review includes discrete complexes of PdL, PdL2, Pd2L, Pd2L2, Pd2L4, and Pd3L6 compositions...
September 19, 2018: Chemistry, An Asian Journal
Hirotaka Nagao, Tomoyo Misawa-Suzuki, Nozomi Tomioka, Haruna Ohno, Masahiro Rikukawa
Nitrosylruthenium complexes bearing two 2,2'-bipyridine (bpy) or 2-pyridinecarboxylate (pyc) ligands, [Ru(NO)X(bpy)2 ]3+ (X=CH3 CN, CH2 =CHCN, H2 O, Cl, ONO2 ) and [Ru(NO)(OH2 )(pyc)2 ]+ , were used as catalysts for the polymerization of acrylonitrile in N,N-dimethylformamide (DMF) under air without initiators to obtain polyacrylonitrile (PAN) with a high molecular weight and a narrow molecular weight distribution.
September 19, 2018: Chemistry, An Asian Journal
Chensheng Ma, Ruth Chau Ting Chan, Chris Tsz-Leung Chan, Allen Ka-Wa Wong, Bowie Po-Yee Chung, Wai-Ming Kwok
I-motifs are tetraplex DNAs known to be stable at acidic pH. The structure of i-motifs is important in DNA nanotechnology while i-motif forming sequences with consecutive cytosines (Cs) are abundant throughout the human genome. There is however little information on structure of C-rich DNAs at the physiologically relevant neutral condition. The electron dynamics of i-motifs, crucial to both the biology and material applications, also remains largely unexplored. In this work, we report a combined femtosecond and nanosecond broadband time-resolved fluorescence (TRF) and steady state fluorescence investigation on homo-oligomer dC20, a human telomeric sequence (HTS) 5'-dC3(TA2C3)3 and its analog performed with different excitation at both acidic and neutral pH...
September 19, 2018: Chemistry, An Asian Journal
Lai-Chang Zhang, Shun-Xing Liang
With an intrinsically disordered atomic structure and a widely tunable atomic constituent, metallic glasses (MGs) as a relative newcomer in the catalytic field have been extensively studied as advanced catalysts. Particularly, Fe-based MGs with superior catalytic activity, relatively low material cost, friendly-environmental compatibility, also emerge as a superior catalyst. This review systematically discusses the recent advances of Fe-based MGs in catalytic applications, including wastewater remediation based on reductive degradation by different Fe-based MGs, oxidative degradation by introduction of advanced oxidation processes (AOPs) and nanocrystallization applied in Fe-based MGs up to date, and renewable energy conversion, with purposes of revealing Fe-based MG catalyst in the further improvement of catalytic performance and exploiting their promising catalytic abilities in a widely catalytic field...
September 18, 2018: Chemistry, An Asian Journal
Jianbo Wang, Kang Wang, Jinghui Yang, Xingqi Yao
Alkyl chromium(0) carbene complexes have been explored as the cross-coupling partners in the palladium-catalyzed reaction with aryl or alkenyl boronic acids. This coupling reaction demonstrates versatile reactivities of alkyl chromium(0) carbenes under palladium-catalysis. Mechanistically, this transformation is proposed to involve deprotonation of alkyl chromium carbene substrate to generate vinyl chromium anion intermediate, which undergoes transmetalation to organopalladium species and reductive elimination...
September 17, 2018: Chemistry, An Asian Journal
Eric D Raftery, Eric G Gharkhanian, Nicole G Ricapito, J McNamara, Timothy J Deming
Biologically occurring non-canonical di-α-amino acids were converted into new di-N-carboxyanhydride (di-NCA) monomers in reasonable yields with high purity. Five different di-NCAs were separately copolymerized with tert-butyl-l-glutamate NCA to obtain covalently crosslinked copolypeptides capable of forming hydrogels with varying crosslinker density. Comparison of hydrogel properties with residue structure revealed that different di-α-amino acids were not equivalent in crosslink formation. Notably, l-cystine was found to produce significantly weaker hydrogels compared to l-homocystine, l-cystathionine, and l-lanthionine, suggesting that l-cystine may be a sub-optimal choice of di-α-amino acid for preparation of copolypeptide networks...
September 17, 2018: Chemistry, An Asian Journal
Haifeng Gao, Xiaosong Cao, Weiping Gan, Yi Shi, Hui Xu
The present study constructed a water-soluble hyperbranched polymer platform that contained Förster resonance energy transfer (FRET) array and exhibited varied fluorescence in response to solvent, light and CN- anion stimuli. The use of chain-growth copper-catalyzed azide-alkyne cycloaddition polymerization (CuAACP) enabled accurate control of the ratio and distance of three incorporated fluorophores: coumarin (Cou), nitrobenzoxadiazole (NBD), and photo-switchable spiropyran (SP) that could be reversibly transformed to its red-emitting merocyanine (MC) state...
September 14, 2018: Chemistry, An Asian Journal
Stephen Andrew Hill, Christoph Gerke, Laura Hartmann
Sequence-control in synthetic polymers is an important contemporary research area because it provides the opportunity to create completely novel materials for structure-function studies. This is especially relevant for biomimetic polymers, bioactive and information security materials. The level of control is strongly dependent and inherent upon the polymerization technique utilized. Today, the most established method yielding monodispersity and monomer sequence-definition is solid phase synthesis. This Focus Review highlights recent advances in solid phase strategies to access synthetic, sequence-defined macromolecules...
September 14, 2018: Chemistry, An Asian Journal
Mrinmoyee Basu
Most important issue in water splitting is the development of efficient, abundant, and cost-effective hydrogen and oxygen evolution catalyst. Development of an efficient electrocatalyst for hydrogen evolution reaction (HER) in alkaline condition is described here following a simple hydrothermal route. In this present study a method for the synthesis of NiCo2S4/Co9S8, Co9S8, and NiCo2S4 nanotubes has been developed. NiCo2S4/Co9S8 heterostructure has been introduced as an efficient electrocatalyst towards HER in alkaline condition (1...
September 12, 2018: Chemistry, An Asian Journal
Pengqing Ye, Yinlin Shao, Leping Xie, Keting Shen, Tianxing Cheng, Jiuxi Chen
A lanthanide-catalyzed intermolecular hydroamination of 2-alkynylbenzonitriles with secondary amines has been disclosed, providing a streamlined access to a range of aminoisoindoles in moderate to excellent yields. The salient features of this reaction include high bond-formation efficiency, mild reaction conditions, 100% atomic efficiency and good functional group tolerance. This methodology has also been successfully applied to the construction of other nitrogen-containing compounds such as 5H-imidazo[2,1-a]isoindoles and isoquinolines...
September 12, 2018: Chemistry, An Asian Journal
David Allan McMorran, Peter J Steel
An M2L4 quadruple helicate, formed by wrapping four molecules of 1,4-bis(3-pyridyloxy)benzene (L1) about two palladium(II) centers, is shown to bind anions within its internal cavity. 1H NMR exchange experiments provide a quantitative measure of anion selectivity and reveal a preference for ClO4- over the other tetrahedral anions BF4- and ReO4- and the octahedral anion PF6-. X-ray crystal structures of [Pd2(L1)4]4+ helicates containing ClO4, BF4- and I- reveal that the cavity size can dynamically change in response to the size of the guest...
September 12, 2018: Chemistry, An Asian Journal
Junwei Zhao, Pei-Jun Gong, Jing-Jing Pang, Hui-Fen Hu, Li-Juan Chen
By virtue of the combining in-situ assembly reaction with stepwise synthesis strategy in the conventional aqueous solution, two series of unique organic-inorganic hybrid heteropolyoxomolybdates constructed from plenary Keggin germanomolybdates and Cu-Ln heterometallic units [H2INA]2H8[LnCu(INA)4(H2O)6]2[α-GeMo12O40]3•52H2O [Ln = La3+ (1), Ce3+ (2), Pr3+ (3), Nd3+ (4), Sm3+ (5), Eu3+ (6); HINA = isonicotinic acid] and (NH4)[Cu(PA)2][Cu(PA)2Ln(H2O)8][α-GeMo12O40]•10H2O [Ln = Nd3+ (7), Sm3+ (8), Eu3+ (9); HPA = picolinic acid] were successfully synthesized and fully characterized...
September 11, 2018: Chemistry, An Asian Journal
Wen-Hua Chiou, Jui-Chi Tsai, Yi-Huei Lin, Guei-Tang Chen, Yu-Kai Gao, Yu-Che Tseng, Chien-Lun Kao
A domino method for the rapid syntheses of 1-azabicyclo[x.y.0]alkane scaffolds such as indolizidines, quinolizidines, decahydropyridoazepines, and their derivatives, has been developed. The strategy used for the construction of the alkaloid scaffolds involves Rh-catalyzed hydroformylation of allyl-, 3-butenyl-, or homoallyl amides, followed by two spontaneous ring closures under mild conditions. By changing the substituent position at amide substrates and altering the carbon chain length of the substrates, the reaction scope and the diastereoselectivity have been fully explored...
September 11, 2018: Chemistry, An Asian Journal
Baoxin Zhang, Yuxin Liu, Xinming Li, Jianqiang Xu, Jianguo Fang
The selenoprotein thioredoxin reductase (TrxR) enzymes are the only identified proteins in maintaining the thioredoxin (Trx) proteins in a reduced state under physiological conditions, and play a pivotal role in regulating various cellular redox signaling pathways involved in cell differentiation, growth and death. The elevated expression of TrxR enzymes has been observed in different types of cancer cells, and this overexpression is of pathological significance in keeping the phenotypes of tumor, such as uncontrolled proliferation and resistance to apoptosis...
September 11, 2018: Chemistry, An Asian Journal
Ji Yu Choi, Jeongyeon Seo, Matthew Park, Mi-Hee Kim, Kyungtae Kang, Insung S Choi
The spatial distribution of cell-surface glycoconjugates in the brain changes continuously, reflecting neurophysiology especially in the developing phase, but their functions and fates mostly remain unexplored. Their spatiotemporal distribution is particularly important in the polarized neuronal cells, such as cerebral cortical neurons composed of a soma and neurites. In this work, we dually labeled sialic acid (Sia5Ac) and N-acetylgalactosamine/glucosamine (GalNAc/GlcNAc) by a neurocompatible strategy of metabolic glycan labeling, metabolism-by-tissues (MbT), and obtained the multiplexed information on their spatiotemporal distribution on the polarized cortical neurons...
September 11, 2018: Chemistry, An Asian Journal
Axel Haupt, Dieter Lentz
Trifluoromethylthio substituted corannulene can be easily synthesized in good yield by the reaction of iodocorannulene with CuSCF3. Oxidation with meta-chloroperbenzoic acid yields the corresponding sulfonyl compound which exhibits the largest anodic shift of the redox potential caused by a single substituent. Similarly, four SCF3, SC6F5 and SeC6F5 substituents are introduced in the 1,2,5,6-positions of corannulene starting with 1,2,5,6-tetraiodo- or 1,2,5,6-tetrabromocorannulene, respectively. The reactions are performed in polar aprotic solvents and are believed to follow SNAr-type substitution mechanisms...
September 11, 2018: Chemistry, An Asian Journal
Ren-Hao Li, Guo-Liang Zhang, Jia-Xing Dong, Ding-Chang Li, Ying Yang, Ying-Ming Pan, Hai-Tao Tang, Li Chen, Zhuang-Ping Zhan
A Co(acac)2/POL-Xantphos@10PPh3-catalyzed hydrosilylation of unsymmetrical internal alkynes with Ph2SiH2 have been firstly developed for the synthesis of highly selectivity syn-α-vinylsilane products. Furthermore, the terminal alkynes was also developed with excellent regioselectivity and wide functional group tolerance. Due to this porous organic polymer combines the selectivity and activity merits of Xantphos ligands with the stability advantage derived from the high concentration of PPh3 ligands and Xantphos firmly coordinated with Co(acac)2, the Co(acac)2/POL-Xantphos@10PPh3 can recycle multiple times without loss of activity and selectivity...
September 11, 2018: Chemistry, An Asian Journal
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