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Dialkylbiaryl Phosphine Ligands
Dialkylbiaryl phosphine ligands are phosphine ligands that are used in homogeneous catalysis. They have proved useful in Buchwald-Hartwig amination and etherification reactions as well as Negishi cross-coupling, Suzuki-Miyaura cross-coupling, and related reactions. In addition to these Pd-based processes, their use has also been extended to transformations catalyzed by nickel, gold, silver, copper, rhodium, and ruthenium, among other transition metals. General features Dialkylbiaryl phosphine ligands are air-stable solids. Many are available commercially. They often can be synthesized in from inexpensive starting materials. One pot protocols have been conducted on >10 kg scales. Their enhanced catalytic activity over other ligands in palladium-catalyzed coupling reactions have been attributed to their electron-richness, steric bulk, and some special structural features. In particular, cyclohexyl, ''t''-butyl, and adamantyl groups on the phosphorus are used for this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal Phosphine Complex
A metal-phosphine complex is a In coordination complex containing one or more phosphine ligands. Almost always, the phosphine is an organophosphine of the type R3P (R = alkyl, aryl). Metal phosphine complexes are useful in homogeneous catalysis. Prominent examples of metal phosphine complexes include Wilkinson's catalyst (Rh(PPh3)3Cl), Grubbs' catalyst, and tetrakis(triphenylphosphine)palladium(0). Preparation Many metal phosphine complexes are prepared by reactions of metal halides with preformed phosphines. For example, treatment of a suspension of palladium chloride in ethanol with triphenylphosphine yields monomeric bis(triphenylphosphine)palladium(II) chloride units. : dCl2sub>n + 2PPh3 → PdCl2(PPh3)2 The first reported phosphine complexes were ''cis''- and ''trans''-PtCl2(PEt3)2 reported by Cahours and Gal in 1870. Often the phosphine serves both as a ligand and as a reductant. This property is illustrated by the synthesis of many platinum-metal complexes of trip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
