Synthesis of methyl-palladium(II) and -platinum(II) complexes containing labile chelates and olefinic tertiary phosphine ligands: intramolecular insertion of an olefin into a palladium–carbon bond, and activation of a carbon–hydrogen bond by a platinum(II) complex

Publisher Website
Google Scholar
Abstract
The square planar complexes [M(Me)(L–L)(L)]{M = Pd, L = dpvp [PPh2(C6H4CHCH2-o)], L–L = acac (acetylacetonate), bzsac (1-phenyl-3-sulfanylbut-2-en-1-onate) or pyca (pyridine-2-carboxylate), L = PPh2(C6H4Et-o), L–L = acac or pyca, L = P(CH2–CHCH2)Ph2, L–L = pyca; M = Pt, L = dpvp, L–L = bzsac or pyca, L = PPh2(C6H4Et-o), L–L = pyca} have been synthesised and their thermal behaviour studied. Heating the palladium–dpvp complexes in benzene leads to intramolecular migratory insertion of the vinyl double bond of the phosphine into the Pd–Me bond to give complexes with a five-membered palladacyclic ring, [Pd(L–L){PPh2(C6H4CHCH2Me)}]. In contrast, warming the platinum complex [PtMe(pyca)(dpvp)] leads to a cyclometallation reaction forming a platinacycle with a platinum–alkenyl bond [Pt(pyca){PPh2(C6H4CCH2)}]. The platinum complex appears to react by oxidative addition of the vinyl C–H bond of dpvp to PtII; methane is eliminated during the reaction. Although no such species has been identified, kinetic evidence suggests that the two thermal processes occur via a common four-co-ordinate intermediate containing a ‘dangling’ pyca ligand and with dpvp chelated through the phosphorus and the vinyl double bond [M(Me)(pyca){PPh2(C6H4CHCH2)}].

This publication has 33 references indexed in Scilit: