The influence of steric bulk on the geometry of triarylphosphite-based palladacycles and their tricyclohexylphosphine adducts

A range of complexes of the formula [PdCl2{P(OAr)3}2] have been synthesized in order to determine the effect of steric bulk on stereochemistry, one example [PdCl2{P(OC6H4-2-tBu)3}2] has been structurally characterized. Three palladacyclic complexes [{Pd(μ-Cl)(κ2-P,C-P(OC6H3R)(OC6H4R)2)}2] have been synthesized (R = H, 2-iPr, 2-tBu) and two have been characterized by crystallography (R = H and tBu). The latter adopts the expected trans geometry while the former is cis. In this case, the driving force for the cis geometry seems to be intermolecular interactions in the crystal structure which are disrupted on substitution. We also report an unusual solvolysis reaction.