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1.
Palladium-catalysed three component coupling of an alkenylbromide, isonitrile and an amine or alkoxide/phenoxide affords α,β-unsaturated-amidines and -imidates. 相似文献
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The role of solvent (and other species) in the formation of networks from tetrakis(thiourea)platinum(II) cations and croconate anions is examined, with crystallisations from DMSO giving rise to a structure containing solvent filled channels. 相似文献
4.
The use of energy selected bases (ESB) with iterative diagonalization of the Hamiltonian matrix is described for vibrations of tetra-atomic systems. The performance of the method is tested by computing vibrational states of HOOH below 10,000 cm(-1) (1296 A+ symmetry states) and H(2)CO below 13,500 cm(-1) (729 A(1) symmetry states). For iterative solutions, we tested both the implicitly restarted Lanczos method (IRLM) and the standard (nonreorthogonalizing) Lanczos approach. Comparison with other contracted basis approach as well as direct product grid representation shows superior performance of the ESB/IRLM approach. Of the two systems, H(2)CO is found to be more challenging than HOOH since it has much stronger couplings among vibrational modes, which leads to a drastically larger primitive basis set. For H(2)CO we also discuss some interesting behavior of the molecule in the high internal energy regime. 相似文献
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Let be a univariant function, and letg(x) be the average of (x,u) asu runs over the unit sphere in
n
. We give a necessary and sufficient condition forg to be a kernel function, i.e., thatg be inL
1 (
n
) and have integral 1. The result is used to give a constructive proof of the density of the ridge functions based upon the function . 相似文献
7.
Xiu Ling ZHANG Wei Min GONG* Bin DAI Chang Hou LIU Plasma Chemistry Laboratory Dalian University of Technology Dalian Center of Analysis Dalian Institute of Light Industry Dalian 《中国化学快报》2002,(2)
The oxidative coupling of methane (OCM) to C2 hydrocarbons using carbon dioxide as oxidant is an attractive process from environmental point of view. Only a few research papers reported for it1-3. In general, the yield of C2 hydrocarbons was about 6%. This indicated that the method of catalytic activation was unfavorable to the reaction. It is necessary for us to find a new method in order to activate reaction and improve C2 hydrocarbon yield. Non-equilibrium plasma is a cold plasma in… 相似文献
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Pennington DA Clegg W Coles SJ Harrington RW Hursthouse MB Hughes DL Light ME Schormann M Bochmann M Lancaster SJ 《Dalton transactions (Cambridge, England : 2003)》2005,(3):561-571
The silyl ethers 3-But-2-(OSiMe3)C6H3CH=NR (2a-e) have been prepared by deprotonation of the known iminophenols (1a-e) and treatment with SiClMe3 (a, R = C6H5; b, R = 2,6-Pri2C6H3; c, R = 2,4,6-Me3C6H2; d, R = 2-C6H5C6H4; e, R = C6F5). 2a-c react with TiCl4 in hydrocarbon solvents to give the binuclear complexes [Ti{3-But-2-(O)C6H3CH=N(R)}Cl(mu-Cl3)TiCl3] (3a-c). The pentafluorophenyl species 2e reacts with TiCl4 to give the known complex Ti{3-But-2-(O)C6H3CH=N(R)}2Cl2. The mononuclear five-coordinate complex, Ti{3-But-2-(O)C6H3CH=N(2,4,6-Me3C6H2)}Cl3 (4c), was isolated after repeated recrystallisation of 3c. Performing the dehalosilylation reaction in the presence of tetrahydrofuran yields the octahedral, mononuclear complexes Ti{3-But-2-(O)C6H3CH=N(R)}Cl3(THF) (5a-e). The reaction with ZrCl4(THF)2 proceeds similarly to give complexes Zr{3-But-2-(O)C6H3CH=N(R)}Cl3(THF) (6b-e). The crystal structures of 3b, 4c, 5a, 5c, 5e, 6b, 6d, 6e and the salicylaldehyde titanium complex Ti{3-But-2-(O)C6H3CH=O}Cl3(THF) (7) have been determined. Activation of complexes 5a-e and 6b-e with MAO in an ethene saturated toluene solution gives polyethylene with at best high activity depending on the imine substituent. 相似文献
10.
We establish a result related to a theorem of de Boor and Jia [1]. Their theorem, in turn, corrected and extended a result of Fix and Strang [5] concerning controlled approximation. In our result, the approximating functions are not required to have compact support, but satisfy instead conditions on their behavior at . Our theorem includes some recent results of Jackson [6] and is closely related to the work of Buhmann [2].Communicated by Carl de Boor 相似文献