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81.
Prof. Dr. Dengrong Sun Lok Wing Wong Hok Yin Wong Ka Hei Lai Dr. Lin Ye Xinyao Xv Prof. Dr. Thuc Hue Ly Prof. Dr. Qingming Deng Prof. Dr. Jiong Zhao 《Angewandte Chemie (International ed. in English)》2023,62(4):e202216008
The direct utilization of metal–organic frameworks (MOFs) for electrocatalytic oxygen evolution reaction (OER) has attracted increasing interests. Herein, we employ the low-dose integrated differential phase contrast-scanning transmission electron microscopy (iDPC-STEM) technique to visualize the atomic structure of multivariate MOFs (MTV-MOFs) for guiding the structural design of bulk MOFs for efficient OER. The iDPC-STEM images revealed that incorporating Fe3+ or 2-aminoterephthalate (ATA) into Ni-BDC (BDC: benzenedicarboxylate) can introduce inhomogeneous lattice strain that weaken the coordination bonds, which can be selectively cleaved via a mild heat treatment to simultaneously generate coordinatively unsaturated metal sites, conductive Ni@C and hierarchical porous structure. Thus, excellent OER activity with current densities of 10 and 100 mA cm−2 are achieved over the defective MOFs at small overpotentials of 286 mV and 365 mV, respectively, which is superior to the commercial RuO2 catalyst and most of the bulk MOFs. 相似文献
82.
S. Bindya Wing‐Tak Wong M. A. Ashok H. S. Yathirajan R. S. Rathore 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):o546-o548
In the structure of the title salt [systematic name: 3‐(10,11‐dihydro‐5H‐dibenzo[a,d][7]annulen‐5‐ylidene)‐N,N‐dimethylpropan‐1‐aminium 2,4,6‐trinitrophenolate] of a tricyclic antidepressant, C20H24N+·C6H2N3O7−, the dimethylaminopropyl subunit possesses a classical static conformational disorder. The central cycloheptadiene ring adopts a bent conformation that is intermediate between boat and chair forms, leading to a butterfly shape for the hetero‐tricyclic moiety. In a complementary fashion, donors from amitriptyline and acceptors from picrate form intermolecular C—H...O hydrogen bonds and N—H...O salt bridges. These hydrogen bonds cluster amitriptyline and picrate ions into a closed R44(36) hetero‐tetramer, whereas intermolecular C—H...π interactions between amitriptyline ions cluster them into homo‐dimers. Significant π–π stacking interactions are also observed between aromatic rings of amitriptyline and picrate, and these, combined with the C—H...π interactions, associate molecules into linear arrays along the [11] direction. 相似文献
83.
The reaction of bisgermavinylidene [(Me3SiN?PPh2)2C?Ge→Ge?C(PPh2?NSiMe3)2] ( 1 ) with AdNCO (Ad = Adamantyl) afforded the [2 + 2] cycloadditon product [(Me3SiN?PPh2)2CGeC(O) NAd] ( 2 ). Similar reaction of 1 with Ph3SiOH in tetrahydrofuran (THF) yielded the base‐stabilized germanium(II) triphenylsiloxide [H2C(PPh2?NSiMe3)2Ge(OSiPh3)2] ( 3 ). The results suggested that reactive germavinylidene may exist in solution and is capable of forming addition reaction products. The X‐ray structures of 2 and 3 were determined. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
84.
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86.
Qing‐Xin Zhang Zhong‐Zhen Yu Mingshu Yang Jun Ma Yiu‐Wing Mai 《Journal of Polymer Science.Polymer Physics》2003,41(22):2861-2869
Nylon‐66 nanocomposites were prepared by melt‐compounding nylon‐66 with organically modified montmorillonite (MMT). The organic MMT layers were exfoliated in a nylon‐66 matrix as confirmed by wide‐angle X‐ray diffraction (WAXD) and transmission electron microscopy. The presence of MMT layers increased the crystallization temperature of nylon‐66 because of the heterogeneous nucleation of MMT. Multiple melting behavior was observed in the nylon‐66/MMT nanocomposites, and the MMT layers induced the formation of form II spherulites of nylon‐66. The crystallite sizes L100 and L010 of nylon‐66, determined by WAXD, decreased with an increasing MMT content. High‐temperature WAXD was performed to determine the Brill transition in the nylon‐66/MMT nanocomposites. Polarized optical microscopy demonstrated that the dimension of nylon‐66 spherulites decreased because of the effect of the MMT layers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2861–2869, 2003 相似文献
87.
88.
Wing Tsang 《国际化学动力学杂志》1976,8(2):193-203
The life times of chemically activated alcohols have been determined using the high-pressure unimolecular rate parameters for thermal decomposition of alcohols from shocktube studies and RRKM calculations. They are compared with literature numbers (from insertion of 0(1D) into hydrocarbons). It is suggested that in some cases singlet oxygen carries excess energy into the hydrocarbon. The consequences of such an assumption are explored and discrepancies with previously published conclusions discussed. 相似文献
89.
Wing Tsang 《国际化学动力学杂志》1969,1(2):245-278
Several hydrocarbons have been pyrolyzed in a single pulse shock tube. Rate parameters for the main bond breaking step have been found to be In combination with similar studies carried out earlier and through application of the well-established experimental rule (k(AB)/kr(AA)kr(BB))1/2 ~ 2 where A and B are radicals and the rate constants are for the combination of these radicals, rate parameters for the thermal decomposition of all the hydrocarbons formed from any pair of the following radicals: methyl, ethyl, isopropyl, t-butyl, t-amyl, allyl, methylallyl, and benzyl have been calculated. The available calculated and experimental values of the decomposition rate constants are in excellent agreement. It appears that, with the possible exception of reactions involving the ejection of methyl radicals, the frequency factors per bond are nearly constant, depending only upon the type of carbon–carbon bond that is being broken. These values are all lower than those expected from the radical recombination rates. Heats of formation of ethyl, t-amyl, benzyl, methylallyl, n-propyl, s-butyl, isobutyl, neopentyl, and 3-pentyl radicals have been derived. Rate parameters for the decomposition of some simple ketones and ethers have also been estimated. 相似文献
90.
W H Okamura M L Hammond A Rego A W Norman R M Wing 《The Journal of organic chemistry》1977,42(13):2284-2291