Palladium diphenyl-2-pyridylphosphine complexes

The stoichiometric reaction of diphenyl-2-pyridylphosphine (Ph2PC5H4N-2) an d palladium(II) acetate afforded the palladium(I) dimer [Pd-2(mu-Ph2PC5H4N) (2)(OAc)(2)] 1. Attempts to is elate the monomer, [Pd(mu Ph2PC5H4N)(2)(OAc) (2)], from 2 : 1 stoichiometry reactions (Ph2PC5H4N : Pd), resulted only in the isolation of 1. When >3 mole equivalents of Ph2PC5H4N were used the ze rovalent palladium complex [Pd(Ph2PC5H4N)(3)] was isolated. Other palladium (I) dimers with carboxylic or sulfonic anionic ligands have been prepared b y a metathesis reaction of the co-ordinated acetates. The complexes 1 and [ Pd-2(mu-Ph2PC5H4N)(2)(O2CCF3)(2)] 2 have been structurally characterised as head-to-tail dimers. The mononuclear complex [Pd(Ph2PC5H4N)(2)(O2CCF3)(2)] has been obtained by reaction of Ph2C5H4N with [Pd(CH3CN)(2)(O2CCF3)(2)]. Complex 1 reacts with dimethyl acetylenedicarboxylate to give [Pd-2(mu-Ph2P C5H4N)(2)-(OAc)(2)(mu-MeO2CC=CCO2Me)], while attempts to isolate an A-frame carbonyl complex were unsuccessful.