Ligand ambivalence in pallada(platina)cyclic complexes of a rigid phosphine

Palladium(II) and platinum(II) complexes of a chiral pentacyclic phosphine, (1S, 4R, 4aS, 5aR, 6R, 9S, 9aS, 10aR)-4,6,11,11,12,12hexamethyl-10-phenyl-dodecahydro-1,4:6,9-dimethano-phenoxaphosphinine (phenop), show diverse structures dependent upon the chosen metal-containing starting material and reaction conditions. With palladium acetate, a P,C-cyclometallated dimeric complex [Pd ((mu)-(kappa)^2-OAc)((mu)- (kappa)^1-OAc)( (kappa)P, (kappa)C14-phenop)]2, 4, is obtained through metallation at the C(14) methyl to form a six-membered chelate. The acetato bridged dimer is readily converted to the halo-bridged species [Pd((mu)-X)( (kappa)P, (kappa)C14-phenop)]2, where X is chloride (5) or bromide (6). Reaction of one equivalent of phenop with Pd(COD)Cl2 or Na2PdCl4 gives a different phosphapalladacycle dimer [Pd((mu)-Cl)((kappa)P, (kappa)C8-phenop)]2, 7, with a five-membered chelate and metallation at the C(8) methylene carbon. The analogous platinum derivative [Pt((mu)-Cl)( (kappa)P, (kappa)C8-phenop)]2, 8, is obtained from the 1 1 reaction of phenop and K2PtCl4. An unusual ligand-ligand coupled product, 9, has been isolated in low yield from the reaction of phenop and Pd(COD)Cl2. The zerovalent Pd((kappa)P-phenop)2, 10, and a monodentate silver(I) derivative, [Ag( P-phenop)(CF3SO3)], 11, have also been prepared. These new complexes have been fully characterised by spectroscopic and other techniques including single crystal X-ray structure determinations of phenop, 7-9 and 11.