Supramolecular 3-/4-Mercaptobenzoic Acid Complexes of Palladium(II) and Platinum(II) Stabilized by Hydrogen Bonding

The reaction of cis-[Pt(PEt3)(2)(OTf)(2)] with 4-mercaptobenzoic acid (4-H(2)mba) in the presence of sodium methoxide yielded trans-[Pt(SC6H4COOH-4)(2)(PEt3)(2)] (1), the simple addition of 3-/4-mercaptobenzoic acid to cis-[Pt(PEt3)(2)(OTf)(2)] and cis-[M(PP)(2)(OTf)(2)] gave the self-assembled complexes cis-[Pt(-SC6H4COOH-n)(PEt3)(2)](2)(OTf)(2) [n = 3 (2), 4 (3)] and [M(-SC6H4COOH-n)(PP)](2)(OTf)(2) [M/n/PP = Pd/3/dppe (4), Pd/4/dppe (5), Pt/4/dppp (6); dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,2-bis(diphenylphosphino)propane], respectively, and the reactions of cis-[PtCl2(PR3)(2)] (R = Et, Ph) and [PtCl2(dppm)] with 3-/4-mercaptobenzoic acids in the presence of triethylamine yielded 1, trans-[Pt(SC6H4COOH-4)(2)(PPh3)(2)] (7) and [Pt(SC6H4COOH-n)(2)(dppm)] [n = 3 (8), 4 (9); dppm = bis(diphenylphosphino)methane], respectively. The complexes 1-4 and 7 form supramolecular assemblies through intermolecular hydrogen bonding in the solid state. A one-dimensional zigzag chain of carboxy dimers is formed in the structures of 1H(2)O and 7, whereas methanol-interrupted large-ring formation leads to a 2D network for 1(MeOH)(2). In the cases of 3(H2O)(2) and 4(H2O)(2), water and counter-anions assisted the formation of 1D networks rather than dimers through carboxylic acid groups.