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631.
Judit E. Puskas Clément Peres Frédéric Peruch Alain Deffieux David E. Dabney Chrys Wesdemiotis Serap Hayat‐Soytaş Allia Lindsay 《Journal of polymer science. Part A, Polymer chemistry》2009,47(8):2181-2189
In this article, we investigate a new bio‐inspired synthetic route towards NR homologs based on the carbocationic polymerization of isoprene initiated by dimethyl allyl alcohol (DMAOH)/TiCl4 or BF3.Et2O as the catalytic system. This study is the continuation of our studies related to the proof of principle that NR biosynthesis is based on a carbocationic mechanism. It is shown that using the biomimetic strategy of initiation by allylic carbocations, polyisoprene carrying a dimethyl allyl head group is produced almost exclusively via 1,4 addition, yielding repeating units with cis and trans configurations. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2181–2189, 2009 相似文献
632.
Daniel Heine Christian Pietsch Ulrich S. Schubert Wolfgang Weigand 《Journal of polymer science. Part A, Polymer chemistry》2013,51(10):2171-2180
Within this study, we report on the first controlled radical polymerization of styrene‐based models of the active site of the [FeFe]‐hydrogenase. Three different model complexes based on styrene were prepared including propanedithiolato‐bridged, 2‐azapropanedithiolato‐bridged, and bifunctional styrene iron complex. These model complexes were copolymerized with styrene using free radical and the reversible addition‐fragmentation chain transfer polymerization method. The polymerization behavior of the hydrogenase models is discussed and analyzed in detail. It could be shown that the model complex can be incorporated into copolymers. The obtained copolymers exhibit narrow molar mass distributions. The presence of the [FeFe]‐hydrogenase models were proven by atomic absorption spectrometry, NMR and IR spectroscopy as well as cyclovoltammetric measurements. It could be shown that the [FeFe]‐hydrogenase mimic copolymers, as well as the monomeric originating complexes exhibit electrocatalytic proton reduction at a low potential of –2.2 V. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
633.
John G. Hardy Thomas R. Scheibel 《Journal of polymer science. Part A, Polymer chemistry》2009,47(16):3957-3963
Natural spider silk fibers have impressive mechanical properties (outperforming many man‐made fibers) and are, moreover, biocompatible, biodegradable, and produced under benign conditions (using water as a solvent at ambient temperature). The problems associated with harvesting natural spider silks inspired us to devise a method to produce spider silk‐like proteins biotechnologically (the first subject tackled in this highlight); we subsequently discuss their processing into various materials morphologies, and some potential technical and biomedical applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3957–3963, 2009 相似文献
634.
635.
Jia‐Qiang Dong Henry N. C. Wong Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(13):2351-2354
Piecing it together : The first total synthesis of naturally occurring diterpene pallavicinolide A was achieved. Notable features are highlighted by three key biomimetic transformations: a base‐promoted Grob fragmentation, a singlet oxygen oxidation, and an intramolecular Diels–Alder cycloaddition.
636.
Partha Halder Sayantan Paria Dr. Tapan Kanti Paine 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(37):11778-11787
An iron(III)–catecholate complex [L1FeIII(DBC)] ( 2 ) and an iron(II)–o‐aminophenolate complex [L1FeII(HAP)] ( 3 ; where L1=tris(2‐pyridylthio)methanido anion, DBC=dianionic 3,5‐di‐tert‐butylcatecholate, and HAP=monoanionic 4,6‐di‐tert‐butyl‐2‐aminophenolate) have been synthesised from an iron(II)–acetonitrile complex [L1FeII(CH3CN)2](ClO4) ( 1 ). Complex 2 reacts with dioxygen to oxidatively cleave the aromatic C? C bond of DBC giving rise to selective extradiol cleavage products. Controlled chemical or electrochemical oxidation of 2 , on the other hand, forms an iron(III)–semiquinone radical complex [L1FeIII(SQ)](PF6) ( 2ox‐PF6 ; SQ=3,5‐di‐tert‐butylsemiquinonate). The iron(II)–o‐aminophenolate complex ( 3 ) reacts with dioxygen to afford an iron(III)–o‐iminosemiquinonato radical complex [L1FeIII(ISQ)](ClO4) ( 3ox‐ClO4 ; ISQ=4,6‐di‐tert‐butyl‐o‐iminobenzosemiquinonato radical) via an iron(III)–o‐amidophenolate intermediate species. Structural characterisations of 1 , 2 , 2ox and 3ox reveal the presence of a strong iron? carbon bonding interaction in all the complexes. The bond parameters of 2ox and 3ox clearly establish the radical nature of catecholate‐ and o‐aminophenolate‐derived ligand, respectively. The effect of iron? carbon bonding interaction on the dioxygen reactivity of biomimetic iron–catecholate and iron–o‐aminophenolate complexes is discussed. 相似文献
637.
Nature bestows many gifts upon us, among which countless biomolecules have the ability to bridge metal ions and exert the important function in biology. By taking advantage of specific interactions between metal ions and biomolecules, this article highlights a novel concept for construction of nanoscale biocoordination polymers through replacement of synthetic organic molecules with natural biomolecules as building blocks. The most recent advances are summarized and future challenges are discussed. It can be anticipated that nanoscale biocoordination polymers will become a diverse and rapidly growing class of novel materials and potentially lead to a breakthrough in biological applications. 相似文献
638.
639.
High costs and low catalytic efficiency of metalloporphyrins, which are an analogue of cytochrome P450 enzyme, are the bot-tlenecks in the industrialization of biomimetic hydrocarbon oxidation reactions. The basic principle and research technique of physical organic chemistry were applied to the process of biomimetic oxidation of hydrocarbon catalyzed by metalloporphyrins. This biomimetic technology could be adapted to bulk chemicals production by developing the new methods for efficient scale-up synthesis of metalloporphyrins, new pathways for molecular oxygen activation on an industrial scale and new approaches to elevate the catalytic efficiency of metalloporphyrins. This review mainly focuses on research carried out in our group. 相似文献
640.
SiO2/聚合物核壳型杂化粒子及其空心结构以其独特的形貌在药物控制释放、催化剂载体、生物医药等领域应用前景广阔,引起了人们的广泛关注。本文着重从乳液聚合法、仿生矿化法等制备方法角度阐述了SiO2/聚合物核壳型杂化粒子及其空心结构的研究进展。乳液聚合制备SiO2/聚合物核壳型杂化粒子简单易行,一般需要预先合成SiO2纳米粒子,其合成过程通常需要一些非理想的条件,如高温高压、极端pH、昂贵或有毒的有机试剂等,而且预先合成的SiO2粒子无法与聚合物实现100%匹配,即总有纯的聚合物粒子存在。相比之下,原位仿生矿化法制备SiO2杂化粒子不仅在环境条件下可进行,而且能够精确控制其纳米尺度的形态及分级有序结构。目前对材料科学家来讲,要使人工合成SiO2/聚合物杂化粒子实现像自然生物硅那样优异的性能,仍然是很大的挑战。 相似文献