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31.
The present feature article highlights the preparation of polymeric nanoparticles and initial attempts towards mimicking the structure of natural biomacromolecules by single chain folding of well‐defined linear polymers through covalent and non‐covalent interactions. Initially, the discussion focuses on the synthesis and characterization of single chain self‐folded structures by non‐covalent interactions. The second part of the article summarizes the folding of single chain polymers by means of covalent interactions into nanoparticle systems. The current state of the art in the field of single chain folding indicates that covalent‐bond‐driven nanoparticle preparation is well advanced, while the first encouraging steps towards building reversible single chain folding systems by the use of mutually orthogonal hydrogen‐bonding motifs have been made. 相似文献
32.
超分子化学是当今化学界的前沿学科之一,超分子主体化合物的选择性合成是其一个重要的方面。环糊精与冠醚同为超分子化学中应用广泛的主体分子,各有自己独特的特点及不足,而将二者偶联起来,可得到拥有两个甚至多个识别位点的化合物,通过协同作用可在分子识别、模拟酶、色谱等方面的应用范围,并有较好的的效果。本文综述了近年来环糊精与冠醚偶联体系的研究进展:首先介绍了不同种类的环糊精与冠醚偶联体系的合成,包括合成思路、步骤以及方法;然后着重叙述了此体系的应用研究进展,包括其在分子识别、模拟酶、异构体分离以及光能量传导等领域;最后指出目前研究工作仍然存在的不足,并对其前景进行了展望。 相似文献
33.
34.
Computational modeling of the kinetics and mechanism of tellurium-based glutathione peroxidase mimic
A new generation of glutathione peroxidase enzyme mimic based on organotellurium was introduced. The catalytic cycles of these mimics, tellura and tellenol, were clarified by density functional theory and solvent-assisted proton exchange procedure as an indirect proton exchange chain. From the kinetic viewpoint, the oxidation of tellura (ΔG≠ = 23.55 kcal mol−1) was considered as the rate-determining step using a single-step process. Various behaviors of tellenol were examined in the reduction of tellurenylsulfide based on methanethiol nucleophilicity. On the basis of the turnover frequency calculations, during the catalytic cycles of tellura and tellenol, the rate of the catalytic cycle of tellura is faster than that of tellenol. A decrease in the electron density and an increase in the Laplacian from the reactant to the transition states are evidence of the bond rupture, whereas an opposite change is evidence of the bond formation. Finally, different analyses of the electron location function and localized orbital locator within the quantum theory of atoms in molecules were applied and discussed. The covalent nature of the intramolecular interactions suggests that the Te⋯N interaction is stronger than that of Te⋯H. Finally, based on different analyses, tellura can be considered the more reactive GPx mimic than tellenol. 相似文献
35.
Bernhard Westermann Nicole Diedrichs Ralf Krelaus Armin Walter Ina Gedrath 《Tetrahedron letters》2004,45(31):5983-5986
Bicyclic lactams serve as building blocks for the synthesis of conformationally restricted peptides. A route to these building blocks is described. They can serve as cis- and trans-peptide bond surrogates. Due to the de novo synthesis, both enantiomeric forms of these products can be produced. Key steps are a lipase-catalyzed saponification of oximes and a highly diastereoselective cyclization utilizing phenylselenyl bromide. In addition, attachment to a solid support has been achieved. 相似文献
36.
Wim M. De Borggraeve Bie M.P. Verbist Frederik J.R. Rombouts Vijaykumar G. Pawar Wim J. Smets Laila Kamoune Jo Alen Erik V. Van der Eycken Frans Compernolle Georges J. Hoornaert 《Tetrahedron》2004,60(50):11597-11612
In this paper, a synthetic approach for functionalised 5-aminopiperidinone-2-carboxylate (APC) systems as non-pro cis-peptide bond containing external β-turn mimics is presented. The scope and limitations of the synthetic method are discussed and the potential turn inducing properties of a model compound are evaluated by means of molecular modelling and NMR analysis. 相似文献
37.
Nicolas Raynal Gilbert Bergé Michel Marraud Jean Martinez 《Tetrahedron letters》2007,48(10):1787-1790
Oligomers derived from dipeptide mimics were selected by computational study for their suitability to fold in ordered structures. After selection of a monomeric unit, short oligomers were synthesized and analyzed by NMR and IR. Oligomers built from 2-aminomethyl-phenyl-acetic acid were shown to adopt a helical structure stabilized by 10-membered ring hydrogen bonds. 相似文献
38.
The Guanidinium Unit in the Catalysis of Phosphoryl Transfer Reactions: From Molecular Spacers to Nanostructured Supports 下载免费PDF全文
Riccardo Salvio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):10960-10971
Examples of guanidinium‐based artificial phosphodiesterases are illustrated in this review article. A wide set of collected catalytic systems are presented, from the early examples to the most recent developments of the use of this unit in the design of supramolecular catalysts. Special attention is dedicated to illustrate the operating catalytic mechanism and the role of guanidine/ium units in the catalysis. One or more of these units can act by themselves or in conjunction with other active units. The analogy with the mechanism of enzymatic systems is presented and discussed. In the last part of this overview, recent examples of guanidinophosphodiesterases based on nanostructured supports are reported, namely gold‐monolayer‐protected clusters and polymer brushes grafted to silica nanoparticles. The issue of the dependence of the catalytic performance on the preorganization of the spacer is tackled and discussed in terms of effective molarity, a parameter that can be taken as a quantitative measurement of this preorganization for both conventional molecular linker and nanosized supports. 相似文献
39.
Dr. Yuhui Wang Jiechen Yao Dr. Zhanglei Cao Dr. Pan Fu Chen Deng Prof. Shifeng Yan Dr. Shuai Shi Prof. Jianping Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(14):e202104174
Carbon dots (CDs) have recently emerged as antibacterial agents and have attracted considerable attention owing to their fascinating merits of small size, facile fabrication, and surface functionalization. Most of them are involved in external light activation or hybridization with other functional nanomaterials. Herein, we present peroxidase-like Cu-doped CDs (Cu-CDs) for in vitro antibacterial applications. The unique peroxidase-mimicking property of the Cu-CDs was demonstrated by tetramethylbenzidine chromogenic assay, electron paramagnetic resonance spectra, and hydroxy radical probe. Escherichia coli and Staphylococcus aureus were chosen as representative gram-negative/positive models against which Cu-CDs exhibited superior antimicrobial activity even at a dosage down to 5 μg/mL. A possible mechanism of action was that the Cu-CDs triggered a catalytic redox reaction of endogenous H2O2 and glutathione depletion in the bacteria cells, with subsequent oxidative stress and membrane disruption. This work provides a new strategy for the design of microenvironment-responsive antimicrobial nano-agents. 相似文献
40.
Miloš R. Filipović Dr. Alaric C. W. Koh Dr. Stéphane Arbault Dr. Vesna Niketić Dr. Andrea Debus Ulrike Schleicher Dr. Christian Bogdan Dr. Manon Guille Dr. Fréderic Lemaître Dr. Christian Amatore Dr. Ivana Ivanović‐Burmazović Dr. 《Angewandte Chemie (International ed. in English)》2010,49(25):4228-4232