Cationic palladium(II)-allyl-complexes containing 2-pyridyldiphenylphosphine: X-ray crystal structure of the binuclear complex [Pd(η3-2-Me-allyl)(μ-Ph2PPy)]2(BF4)2. Detection of an intramolecular C(allyl)–H⋯phenyl ring π-interaction

Reaction of [PdCl(η3-2-Me-allyl)(Ph2PPy)] (1) with AgBF4 affords the new dinuclear cationic complex [Pd(η3-2-Me-allyl)(μ-Ph2PPy)]2(BF4)2 (2). The X-ray structural analysis of 2 shows that the 2-pyridyldiphenylphosphine ligands adopt a binucleating role through the P and N atoms bridging two independent palladium centres to form an eight-membered metallocyclic ring. One of the anti hydrogen atoms of the allyl moiety was located very close to a phenyl ring of Ph2PPy indicating the occurrence of a CH/π interaction. Addition of one equivalent of Ph2PPy to complex (2) affords the mononuclear cationic complex [Pd(η3-2-Me-allyl)(Ph2PPy)2](BF4) (3).