Platinum allenylidene complexes and formation of platinum and palladium acetonitrile alkynyl complexes
作者:Florian Kessler、Evelyn Wuttke、Daniela Lehr、Yan Wang、Bernhard Weibert、Helmut Fischer
DOI:10.1016/j.ica.2011.02.074
日期:2011.8
The platinum(0) complex [Pt(PPh3)(4)] reacts with brominated propargylic amides and esters in benzene by oxidative addition to give trans-[Br(PPh3)(2)Pt-C C-C(=O)R] complexes whereas no reaction occurs when halogenated solvents (CH2Cl2, CHCl3) are used. The cis-ligands PPh3 can be replaced by P(Pr-i)(3) and the bromide by trifluoroacetate. O-Alkylation of those trans-[X(PR'(3))(2)Pt-C C-C(=O)R] complexes (X = Br, CF3COO; R' = Ph, Pr-i) derived from propargylic amides with MeOTf or [Me3O]BF4 in CH2Cl2 gives the first cationic monoallenylidene complexes of platinum, trans-[X(PR'(3))(2)Pt=C=C=C(OMe)NR2](+) Y (Y = OTf, BF4). In contrast, trans-[Br(PPh3)(2)Pt-C C-C(=O)OMenthyl] derived from a propargylic ester does not react with MeOTf in CH2Cl2. However, in acetonitrile instead of O-methylation the substitution of acetonitrile for the bromide ligand to yield the cationic acetonitrile alkynyl platinum complex trans-[MeCN(PPh3)(2)Pt-C C-C(=O)OMenthyl](+) OTf is observed. The related palladium complexes trans-[X(PR'(3))(2)Pd-C C-C(=O)OR] (X = Br, CF3COO; R' = Ph, Pr-i, R = menthyl, Et) react with MeOTf or [Et3O]BF4 analogously affording trans-[MeCN(PR'(3))(2)Pd-C C-C(=O)OR](+) Y (Y = OTf, BF4). (C) 2011 Elsevier B.V. All rights reserved.