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28 Apr 14:06

Enzyme-MOF (metal-organic framework) composites

Chem. Soc. Rev., 2017, 46,3386-3401
DOI: 10.1039/C7CS00058H, Review Article
Xizhen Lian, Yu Fang, Elizabeth Joseph, Qi Wang, Jialuo Li, Sayan Banerjee, Christina Lollar, Xuan Wang, Hong-Cai Zhou
This review summarizes the syntheses and applications of metal-organic framework (MOF)-enzyme composites with specific emphasis on the merits MOFs bring to the immobilized enzymes.
The content of this RSS Feed (c) The Royal Society of Chemistry
19 Aug 16:49

Molecular Catalysis of the Electrochemical and Photochemical Reduction of CO2 with Earth-Abundant Metal Complexes. Selective Production of CO vs HCOOH by Switching of the Metal Center

by Lingjing Chen, Zhenguo Guo, Xi-Guang Wei, Charlotte Gallenkamp, Julien Bonin, Elodie Anxolabéhère-Mallart, Kai-Chung Lau, Tai-Chu Lau and Marc Robert

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/jacs.5b06535
13 Jan 14:30

Pd embedded in chitosan microspheres as tunable soft-materials for Sonogashira cross-coupling in water-ethanol mixture

Green Chem., 2015, 17,1893-1898
DOI: 10.1039/C4GC02175D, Paper
Sana Frindy, Ana Primo, Mohamed Lahcini, Mosto Bousmina, Hermenegildo Garcia, Abdelkrim El Kadib
Easy shaping of chitosan (CS) as self-standing microspheres and functionalisation of its amino groups afford heterogeneous Pd-supported catalysts for Sonogashira cross-coupling.
The content of this RSS Feed (c) The Royal Society of Chemistry
30 Jul 14:24

Microwave-assisted synthesis of plate-like SAPO-34 nanocrystals with increased catalyst lifetime in the methanol-to-olefin reaction

Catal. Sci. Technol., 2014, 4,4330-4339
DOI: 10.1039/C4CY00775A, Paper
T. Alvaro-Munoz, E. Sastre, C. Marquez-Alvarez
Microwave mediated synthesis produced SAPO-34 nanocrystals with increased catalyst lifetime in the methanol-to-olefin reaction owing to their plate-like crystal shape.
The content of this RSS Feed (c) The Royal Society of Chemistry
18 Jul 08:58

Synthesis and Structural Characterization of β-Ketoiminate-Stabilized Gallium Hydrides for Chemical Vapor Deposition Applications

by Peter Marchand, David Pugh, Ivan P. Parkin, Claire J. Carmalt

Abstract

Bis-β-ketoimine ligands of the form [(CH2)n{N(H)C(Me)[BOND]CHC(Me)[DOUBLE BOND]O}2] (LnH2, n=2, 3 and 4) were employed in the formation of a range of gallium complexes [Ga(Ln)X] (X=Cl, Me, H), which were characterised by NMR spectroscopy, mass spectrometry and single-crystal X-ray diffraction analysis. The β-ketoimine ligands have also been used for the stabilisation of rare gallium hydride species [Ga(Ln)H] (n=2 (7); n=3 (8)), which have been structurally characterised for the first time, confirming the formation of five-coordinate, monomeric species. The stability of these hydrides has been probed through thermal analysis, revealing stability at temperatures in excess of 200 °C. The efficacy of all the gallium β-ketoiminate complexes as molecular precursors for the deposition of gallium oxide thin films by chemical vapour deposition (CVD) has been investigated through thermogravimetric analysis and deposition studies, with the best results being found for a bimetallic gallium methyl complex [L3{GaMe2}2] (5) and the hydride [Ga(L3)H] (8). The resulting films (F5 and F8, respectively) were amorphous as-deposited and thus were characterised primarily by XPS, EDXA and SEM techniques, which showed the formation of stoichiometric (F5) and oxygen-deficient (F8) Ga2O3 thin films.

Thumbnail image of graphical abstract

Making vapor: Thermally stable gallium hydrides are formed by utilizing tetradentate β-ketoimine ligand systems (see scheme). The monomeric species are isolated and structurally characterized, and their application as molecular precursors to gallium oxide thin films is also shown. The study highlights the potential of this ligand class for the facile preparation of traditionally unstable species, rendering them suitable for further application in materials fabrication.

17 Jul 09:21

Solution-Processable Hosts Constructed by Carbazole/PO Substituted Tetraphenylsilanes for Efficient Blue Electrophosphorescent Devices

by He Liu, Qing Bai, Liang Yao, Dehua Hu, Xiangyang Tang, Fangzhong Shen, Huanhuan Zhang, Yu Gao, Ping Lu, Bing Yang, Yuguang Ma

Two new solution-processable wide bandgap materials, bis(4-((4-(9-H-carbazol-9-yl)phenyl)diphenylsilyl)phenyl)(phenyl)phosphine oxide (CS2PO) and bis(4-((4-(9-H-(3,9′-bicarbazol)-9-yl)phenyl)diphenylsilyl)phenyl)(phenyl)phosphine oxide (DCS2PO), have been developed for blue phosphorescent light-emitting diodes by coupling an electron-donating carbazole moiety and an electron-accepting PO unit together via double-silicon bridges. Both of them have been characterized as having high glass transition temperatures of 159–199 °C, good solubility in common organic solvent (20 mg mL−1), wide optical gap (3.37–3.55 eV) and high triplet energy levels (2.97–3.04 eV). As compared with their corresponding single-silicon bridged compounds, this design strategy of extending molecular structure endows CS2PO and DCS2PO with higher thermal stability, better solution processability and more stable film morphology without lowering their triplet energies. As a result, DCS2PO/FIrpic doped blue phosphorescent device fabricated by spin-coating method shows the best electroluminescent performance with a maximum current efficiency of 26.5 cd A−1, a maximum power efficiency of 8.66 lm W−1, and a maximum external quantum efficiency of 13.6%, which is one of the highest efficiencies among small molecular devices with the same deposition process and device configuration.

Thumbnail image of graphical abstract

Solution-processable wide-bandgap materials are synthesized by incorporating carbazole and PO moieties into double-bridged tetraphenylsilanes. This design strategy endows them with good solubility, high thermal stability, and excellent film-forming ability without lowering the triplet energies. A maximum current efficiency of 26.5 cd A−1 and external quantum efficiency of 13.6% is achieved for DCS2PO/FIrpic blue phosphorescent device.

03 Aug 03:51

Design of meso-TiO2@MnOx-CeOx/CNTs with a core-shell structure as DeNOx catalysts: promotion of activity, stability and SO2-tolerance

Nanoscale, 2013, 5,9821-9829
DOI: 10.1039/C3NR03150K, Paper
Lei Zhang, Dengsong Zhang, Jianping Zhang, Sixiang Cai, Cheng Fang, Lei Huang, Hongrui Li, Ruihua Gao, Liyi Shi
We have designed a core-shell structural deNOx catalyst to promote the catalytic activity, stability and SO2-tolerance.
The content of this RSS Feed (c) The Royal Society of Chemistry
11 Jul 14:52

MnO@Carbon Core–Shell Nanowires as Stable High-Performance Anodes for Lithium-Ion Batteries

by Xiaowei Li, Shenglin Xiong, Jingfa Li, Xin Liang, Jiazhao Wang, Jing Bai, Yitai Qian

Abstract

A facile method is presented for the large-scale preparation of rationally designed mesocrystalline MnO@carbon core–shell nanowires with a jointed appearance. The nanostructures have a unique arrangement of internally encapsulated highly oriented and interconnected MnO nanorods and graphitized carbon layers forming an external coating. Based on a comparison and analysis of the crystal structures of MnOOH, Mn2O3, and MnO@C, we propose a sequential topotactic transformation of the corresponding precursors to the products. Very interestingly, the individual mesoporous single-crystalline MnO nanorods are strongly interconnected and maintain the same crystallographic orientation, which is a typical feature of mesocrystals. When tested for their applicability to Li-ion batteries (LIB), the MnO@carbon core–shell nanowires showed excellent capacity retention, superior cycling performance, and high rate capability. Specifically, the MnO@carbon core–shell nanostructures could deliver reversible capacities as high as 801 mA h g−1 at a high current density of 500 mA g−1, with excellent electrochemical stability after testing over 200 cycles, indicating their potential application in LIBs. The remarkable electrochemical performance can mainly be attributed to the highly uniform carbon layer around the MnO nanowires, which is not only effective in buffering the structural strain and volume variations of anodes during repeated electrochemical reactions, but also greatly enhances the conductivity of the electrode material. Our results confirm the feasibility of using these rationally designed composite materials for practical applications. The present strategy is simple but very effective, and appears to be sufficiently versatile to be extended to other high-capacity electrode materials with large volume variations and low electrical conductivities.

Thumbnail image of graphical abstract

MnO-based nanowires: MnO@C core–shell composite nanostructures with a jointed appearance can be prepared via Mn2O3 (see scheme). The nanostructures consist of internally encapsulated MnO and carbon layers forming an exterior coating. These MnO@C core–shell nanowires show relatively good capacity retention, thus making them promising materials for application in lithium-ion batteries.