Mechanism of the formation of cyclobutadiene–palladium chloride complexes: the X-ray structures of [Pd(bipy){CButCMeCMeCButCl}Cl] and [Pd2Cl3(η4-C4But2Me2)2]2[Pd2Cl6]

Abstract

At low temperatures Bu^tCCMe reacts with PdCl₂(PhCN)₂ to give complexes [PdCl(Q)X][where Q is the σ-butadienyl ligand -C(Bu^t)CMeCMeCBu^tCl and X =½(PdCl₂), PdCl₂(PhCN), or PdClQ], characterised as [Pd(Q)(acac)](Hacac = acetylacetone) and by an X-ray structure of [Pd(Q)(bipy)Cl](bipy = 2,2′-bipyridyl); the complexes [PdCl(Q)X] rearrange to the cyclobutadiene complexes [{PdCl₂(C₄Bu^t₂Me₂)}₂] or [Pd₂Cl₃(C₄Bu^t₂Me₂)₂]₂[Pd₂Cl₆], the latter being identified by an X-ray determination.