共查询到20条相似文献,搜索用时 15 毫秒
1.
Zhicheng Zhang Yifeng Chen Xiaobin Xu Jingchao Zhang Guolei Xiang Wei He Prof. Xun Wang 《Angewandte Chemie (International ed. in English)》2014,53(2):429-433
Metal–organic frameworks (MOFs) have demonstrated great potentials in a variety of important applications. To enhance the inherent properties and endow materials with multifunctionality, the rational design and synthesis of MOFs with nanoscale porosity and hollow feature is highly desired and remains a great challenge. In this work, the formation of a series of well‐defined MOF (MOF‐5, FeII‐MOF‐5, FeIII‐MOF‐5) hollow nanocages by a facile solvothermal method, without any additional supporting template is reported. A surface‐energy‐driven mechanism may be responsible for the formation of hollow nanocages. The addition of pre‐synthesized poly(vinylpyrrolidone)‐ (PVP) capped noble‐metal nanoparticles into the synthetic system of MOF hollow nanocages yields the yolk–shell noble metal@MOF nanostructures. The present strategy to fabricate hollow and yolk–shell nanostructures is expected to open up exciting opportunities for developing a novel class of inorganic–organic hybrid functional nanomaterials. 相似文献
2.
《化学:亚洲杂志》2017,12(24):3203-3207
The self‐assembly process of a Pd12L24 sphere was revealed by a quantitative approach (quantitative analysis of self‐assembly process: QASAP) quantifying all the substrates, the products, and the observable intermediates, indicating that the Pd12L24 sphere is produced through several pathways. Firstly, Pdn L2n (n= 6, 8, and 9), which are perfectly closed structures smaller than the Pd12L24 sphere, and a mixture of intermediates not observed by NMR ( Int ) were produced. Next, the sphere was assembled from intra‐/intermolecular reaction of a certain class of Int (path A) and from the coordination of free pyridyl groups in Int to the PdII center of Pdn L2n (n= 6, 8, and 9) (path B). While capping the free pyridyl groups in Int with PdII ions perfectly inhibited the sphere formation, the addition of free L to Int accelerated the formation of the sphere. 相似文献
3.
Ken‐ichi Otake Dr. Kazuya Otsubo Dr. Kunihisa Sugimoto Prof. Akihiko Fujiwara Prof. Hiroshi Kitagawa 《Angewandte Chemie (International ed. in English)》2016,55(22):6448-6451
We report the structural design and control of electronic states of a new series of ultrafine metal–organic right square prism‐shaped nanowires. These nanowires have a very small inner diameter of about 2.0 Å, which is larger than hydrogen and similar to xenon atomic diameters. The electronic states of nanowires can be widely controlled by substitution of structural components. Moreover, the platinum homometallic nanowire shows a 100 times higher proton conductivity than a palladium/platinum heterometallic one depending on the electronic states. 相似文献
4.
5.
Dr. Ada Della Pia Dr. Massimo Riello James Lawrence Dr. Daphne Stassen Prof. Tim S. Jones Prof. Davide Bonifazi Prof. Alessandro De Vita Prof. Giovanni Costantini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8105-8112
Two‐dimensional metal–organic nanostructures based on the binding of ketone groups and metal atoms were fabricated by depositing pyrene‐4,5,9,10‐tetraone (PTO) molecules on a Cu(111) surface. The strongly electronegative ketone moieties bind to either copper adatoms from the substrate or codeposited iron atoms. In the former case, scanning tunnelling microscopy images reveal the development of an extended metal–organic supramolecular structure. Each copper adatom coordinates to two ketone ligands of two neighbouring PTO molecules, forming chains that are linked together into large islands through secondary van der Waals interactions. Deposition of iron atoms leads to a transformation of this assembly resulting from the substitution of the metal centres. Density functional theory calculations reveal that the driving force for the metal substitution is primarily determined by the strength of the ketone–metal bond, which is higher for Fe than for Cu. This second class of nanostructures displays a structural dependence on the rate of iron deposition. 相似文献
6.
Nathan J. Oldenhuis K. Peter Qin Shu Wang Hong‐Zhou Ye Eric A. Alt Adam P. Willard Troy Van Voorhis Stephen L. Craig Jeremiah A. Johnson 《Angewandte Chemie (International ed. in English)》2020,59(7):2784-2792
Photoresponsive materials that change in response to light have been studied for a range of applications. These materials are often metastable during irradiation, returning to their pre‐irradiated state after removal of the light source. Herein, we report a polymer gel comprising poly(ethylene glycol) star polymers linked by Cu24L24 metal–organic cages/polyhedra (MOCs) with coumarin ligands. In the presence of UV light, a photosensitizer, and a hydrogen donor, this “polyMOC” material can be reversibly switched between CuII, CuI, and Cu0. The instability of the MOC junctions in the CuI and Cu0 states leads to network disassembly, forming CuI/Cu0 solutions, respectively, that are stable until re‐oxidation to CuII and supramolecular gelation. This reversible disassembly of the polyMOC network can occur in the presence of a fixed covalent second network generated in situ by copper‐catalyzed azide‐alkyne cycloaddition (CuAAC), providing interpenetrating supramolecular and covalent networks. 相似文献
7.
Cover Picture: Two‐Dimensional Ketone‐Driven Metal–Organic Coordination on Cu(111) (Chem. Eur. J. 24/2016)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Ada Della Pia Dr. Massimo Riello James Lawrence Dr. Daphne Stassen Prof. Tim S. Jones Prof. Davide Bonifazi Prof. Alessandro De Vita Prof. Giovanni Costantini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):7989-7989
8.
9.
Cui-Lian Liu Eduard O. Bobylev Yang Fu David A. Poole III Dr. Koen Robeyns Prof. Dr. Charles-André Fustin Prof. Dr. Yann Garcia Prof. Dr. Joost N. H. Reek Prof. Dr. Michael L. Singleton 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(52):11960-11965
Non-covalent interactions are important for directing protein folding across multiple intermediates and can even provide access to multiple stable structures with different properties and functions. Herein, we describe an approach for mimicking this behavior in the self-assembly of metal–organic cages. Two ligands, the bend angles of which are controlled by non-covalent interactions and one ligand lacking the above-mentioned interactions, were synthesized and used for self-assembly with Pd2+. As these weak interactions are easily broken, the bend angles have a controlled flexibility giving access to M2( L1 )4, M6( L2 )12, and M12( L2 )24 cages. By controlling the self-assembly conditions this process can be directed in a stepwise fashion. Additionally, the multiple endohedral hydrogen-bonding sites on the ligand were found to play a role in the binding and discrimination of neutral guests. 相似文献
10.
11.
Prof. Dr. Zhonghao Li Rui Li Dr. Tiancheng Mu Dr. Yuxia Luan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):6005-6013
Morphology‐ and composition‐controlled synthesis of Au–Pd bimetallic particles was realized by a facile ionic liquid assisted route at room temperature. The morphologies of the synthesized particles, such as nanoflake‐constructed spheres with a core–shell structure, nanoparticle‐constructed spheres, and nanoparticle‐constructed dendrites, could be well controlled by the present route. The ionic liquid was found to play a key role in the formation of these interesting particles. Moreover, the composition (Au:Pd) of the particles could be modulated by means of the molar ratio of the metal precursors in the feeding solutions. The Au–Pd bimetallic particles exhibit high electrocatalytic activity toward oxidation of ethanol and formic acid. Furthermore, cyclic voltammetric studies on the as‐prepared Au–Pd bimetallic particles revealed good electroactivity for H2O2, which results in an effective amperometric H2O2 sensor. 相似文献
12.
13.
14.
Di Wang Dr. Alberto Villa Dr. Paolo Spontoni Dang Sheng Su Dr. Laura Prati Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(33):10007-10013
The catalytic oxidation of alcohols with molecular oxygen on supported nanometallic catalysts represents one of the green methods in a crucial process for the synthesis of fine chemicals. We have designed an experiment using physically mixed Au/AC and Pd/AC (AC=activated carbon) as the catalyst in the liquid‐phase oxidation of benzyl alcohol by aerobic oxygen. The evolution of the physically mixed catalyst structures at different stages in the catalytic reaction was investigated by aberration‐corrected high‐resolution transmission electron microscopy and spatially resolved element mapping techniques at the nanometre scale, and they were also compared with the structure of the bimetallic alloy. For the first time we show the formation of surface Au–Pd bimetallic sites by reprecipitation of Pd onto Au nanoparticles. Negligible Au leaching was observed. The in situ structural evolution can be directly correlated to the great enhancement of the catalyst activity. Moreover, we distinguish the different behaviours of Au and Pd, thus suggesting an oxygen differentiating mechanism for Au and Pd sites. The findings are of great importance to both the understanding of the structure–activity correlation and the design of highly active catalysts in green chemistry. 相似文献
15.
16.
17.
Qi‐Zhi Zhong Joseph J. Richardson Shiyao Li Wenjie Zhang Yi Ju Jianhua Li Shuaijun Pan Jingqu Chen Frank Caruso 《Angewandte Chemie (International ed. in English)》2020,59(4):1711-1717
Functional coatings are of considerable interest because of their fundamental implications for interfacial assembly and promise for numerous applications. Universally adherent materials have recently emerged as versatile functional coatings; however, such coatings are generally limited to catechol, (ortho‐diphenol)‐containing molecules, as building blocks. Here, we report a facile, biofriendly enzyme‐mediated strategy for assembling a wide range of molecules (e.g., 14 representative molecules in this study) that do not natively have catechol moieties, including small molecules, peptides, and proteins, on various surfaces, while preserving the molecule's inherent function, such as catalysis (≈80 % retention of enzymatic activity for trypsin). Assembly is achieved by in situ conversion of monophenols into catechols via tyrosinase, where films form on surfaces via covalent and coordination cross‐linking. The resulting coatings are robust, functional (e.g., in protective coatings, biological imaging, and enzymatic catalysis), and versatile for diverse secondary surface‐confined reactions (e.g., biomineralization, metal ion chelation, and N‐hydroxysuccinimide conjugation). 相似文献
18.
Perturbation of Spin Crossover Behavior by Covalent Post‐Synthetic Modification of a Porous Metal–Organic Framework
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
John E. Clements Dr. Jason R. Price Dr. Suzanne M. Neville Prof. Cameron J. Kepert 《Angewandte Chemie (International ed. in English)》2014,53(38):10164-10168
Covalent post‐synthetic modification is a versatile method for gaining high‐level synthetic control over functionality within porous metal–organic frameworks and for generating new materials not accessible through one‐step framework syntheses. Here we apply this topotactic synthetic approach to a porous spin crossover framework and show through detailed comparison of the structures and properties of the as‐synthesised and covalently modified phases that the modification reaction proceeds quantitatively by a thermally activated single‐crystal‐to‐single‐crystal transformation to yield a material with lowered spin‐switching temperature, decreased lattice cooperativity, and altered color. Structure–function relationships to emerge from this comparison show that the approach provides a new route for tuning spin crossover through control over both outer‐sphere and steric interactions. 相似文献
19.
Pd Nanocubes@ZIF‐8: Integration of Plasmon‐Driven Photothermal Conversion with a Metal–Organic Framework for Efficient and Selective Catalysis
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Qihao Yang Prof. Dr. Qiang Xu Prof. Dr. Shu‐Hong Yu Prof. Dr. Hai‐Long Jiang 《Angewandte Chemie (International ed. in English)》2016,55(11):3685-3689
Composite nanomaterials usually possess synergetic properties resulting from the respective components and can be used for a wide range of applications. In this work, a Pd nanocubes@ZIF‐8 composite material has been rationally fabricated by encapsulation of the Pd nanocubes in ZIF‐8, a common metal–organic framework (MOF). This composite was used for the efficient and selective catalytic hydrogenation of olefins at room temperature under 1 atm H2 and light irradiation, and benefits from plasmonic photothermal effects of the Pd nanocube cores while the ZIF‐8 shell plays multiple roles; it accelerates the reaction by H2 enrichment, acts as a “molecular sieve” for olefins with specific sizes, and stabilizes the Pd cores. Remarkably, the catalytic efficiency of a reaction under 60 mW cm?2 full‐spectrum or 100 mW cm?2 visible‐light irradiation at room temperature turned out to be comparable to that of a process driven by heating at 50 °C. Furthermore, the catalyst remained stable and could be easily recycled. To the best of our knowledge, this work represents the first combination of the photothermal effects of metal nanocrystals with the favorable properties of MOFs for efficient and selective catalysis. 相似文献