排序方式: 共有84条查询结果,搜索用时 15 毫秒
1.
E. Maria Claesson Nilesh C. Mehendale Robertus J.M. Klein Gebbink Gerard van Koten Albert P. Philipse 《Journal of magnetism and magnetic materials》2007
Monodisperse magnetizable colloidal silica particles in a stable dispersion have been functionalized with a homogeneous catalyst: a PCP–pincer Pd-complex. In a proof-of-principle experiment we demonstrate the catalytic activity of the colloids in a C–C bond formation reaction. Advantages of the magnetic silica carriers are the large surface-to-volume ratio and the easy recovery by magnetic separation. After magnetic separation, the catalyst-loaded particles are readily redispersed for further use. 相似文献
2.
Irina P. Beletskaya 《Journal of organometallic chemistry》2004,689(24):4055-4082
The application of palladacycles as catalysts for cross-coupling and similar reactions is reviewed. In the majority of cases palladacycles are likely to serve as a source of highly active but unstable zero-valent palladium species. In this respect the palladacycles resemble the so-called phosphine-free catalysts. The advantages and limitations of palladacycle catalysts are discussed. 相似文献
3.
Xiaoling Bao Jianhong Liu Qingshu Zheng Wei Pei Yimei Yang Yanyun Dai Tao Tu 《中国化学快报》1990,30(12):2266-2270
A novel protocol allowing convenient and highly selective visual recognition of melamine in raw milk via selective metallo-hydrogel formation at a concentration as low as 10 ppm without any tedious pretreatment has been developed. 相似文献
4.
Valente Gómez-Benítez 《Tetrahedron letters》2006,47(29):5059-5062
[NiCl{C6H3-2,6-(OPPh2)2}] efficiently catalyzes the thiolation of iodobenzene with a broad scope of disulfides in the presence of zinc, the coupled products are obtained in excellent and in many cases nearly quantitative yields. 相似文献
5.
Patrik Nilsson 《Journal of organometallic chemistry》2005,690(18):4197-4202
An investigation of the kinetics of the Heck reaction between 4-iodoanisole and styrene catalysed by {cis-1,3-bis[(di-tert-butylphosphino)methyl]-cyclohexane} palladium (II) iodide (1) has been performed in DMF-d7 solution. Based on mercury poisoning experiments a heterogeneous palladium catalyst formed from the pre-catalyst is proposed. Saturation behaviour with respect to the olefin concentration suggests a mechanism consisting of a pre-equilibrium association of the olefin followed by a rate determining reaction with aryl halide. The equilibrium constant for the olefin association, K1, and the rate constant for the subsequent oxidative addition step, k2, were determined to (5.7 ± 2.5) × 10−3 and 18.4 ± 2.7 M−1 s−1, respectively. 相似文献
6.
An asymmetric 1,6-addition of diphenylphosphine to (4-aryl-1,3-butadienylidene)bis(phosphonates) catalyzed by a PCP pincer–Pd complex has been developed for the synthesis of chiral allylic phosphines with up to 91% ee under mild conditions. 相似文献
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8.
Konstantin A. Kozhanov Michael P. Bubnov Nina N. Vavilina Larisa Yu. Efremova Georgy K. Fukin Vladimir K. Cherkasov Gleb A. Abakumov 《Polyhedron》2009,28(13):2555-2558
Structural study of dialkyl (PCP)-pincer o-semiquinonato nickel complexes indicated sloped relative positions of bi- and tri-dentate ligands. It became bright confirmation of propositions made on the base of their EPR spectra followed by molecular modelling. 相似文献
9.
A terminal palladium (II) fluoride complex (FPNP)PdF (where FPNP is a an anionic fluoro-substituted diarylamido/bis(phosphine) pincer ligand) has been prepared and characterized spectroscopically and structurally. An X-ray diffraction study revealed an approximately square-planar environment about Pd and a short Pd-F bond distance. (FPNP)PdF reacted with silanes containing electron-withdrawing groups on Si by exchange of fluoride with one of the substituents on Si. An analysis of the 19F chemical shifts of both the Pd-bound fluoride and of the fluorines on the backbone of the FPNP ligand is provided. 相似文献
10.
Our methodology for the stoichiometric preparation of CCC-NHC pincer complexes of Zr has been extended to Hf. The CCCBu-NHC pincer Hf complex has been characterized by X-ray crystal structure analysis. Catalytic activity in the intramolecular hydroamination/cyclization of unactivated alkenes is reported and compared to the recently reported Zr analog. An improved, scaled-up CuO-catalyzed aryl amination of 1,3-dibromobenzene and an improved salt formation methodology for preparation of bis(butyl-imidazolium)benzene are reported also. 相似文献