Chelate-stabilised alcohol- and alkoxo-palladium(II) complexes derived from the ligands Ph2PCH2CR2OH (R = Me or H)

Abstract

The ligands Ph₂PCH₂CRR′OH [R = R′= Me (1a), R = Me, R′= H(1b); R = R′= H (1c)] form complexes of stoicheiometry PdCl₂(Ph₂PCH₂CRR′OH)₂ which are in the neutral form trans-[PdCl₂(Ph₂PCH₂CRR′OH)₂] where R, R′= Me or H(2a)—(2c) in CDCl₃ solution, and the ionic form cis-[P[graphic omitted]H)(Ph₂PCH₂CRR′OH)]Cl, where R = R′= Me (4a) or R = Me, R′= H (4b) in CD₃OD solution. The complex [PdCl₂(Ph₂PCH₂CH₂OH)₂] dissolves in D₂O to give an acidic solution of pH 3.9. Treatment of trans-[PdCl₂(Ph₂PCH₂CRR′OH)₂](2a) or (2b) with AgClO₄ in acetone gives cis-[P[graphic omitted]H)₂][ClO₄]₂(6a) or (6b). Deprotonation of (6a) or (6b) with Et₃N in CDCl₃ or deprotonation of [PdCl₂(Ph₂PCH₂CRR′OH)₂](2a)—(2c) with NaOH in ethanol gave the bis(alkoxo) complexes [P[graphic omitted])₂](7a)—(7c). Deprotonation of [PdCl₂(Ph₂PCH₂CH₂OH)₂](2c) with Et₃N in CDCl₃ gave a mixture of three Pd species, including the binuclear complex [P[graphic omitted])₂(Ph₂PCH₂CH₂OH)₂]Cl₂(9). All products have been characterised by a combination of elemental analysis, i.r., ¹H, and ³¹P n.m.r. spectroscopy.