REACTION OF TETRAACETATOCHLORODIRUTHENIUM(II,III) WITH PYRIDINE-2-CARBOXYLIC ACID - X-RAY CRYSTAL-STRUCTURES OF TRIS(PYRIDINE-2-CARBOXYLATO-KAPPA-N,O)RUTHENIUM(III) MONOHYDRATE AND TRANS-BIS(PYRIDINE-2-CARBOXYLATO-KAPPA-N,O)BIS(TRIPHENYLPHOSPHINE)RUTHENIUM(II)-METHANOL(1/2)

The reaction of [Ru2Cl(mu-O2CMe)4] with pyridine-2-carboxylic acid (Hpyca) in methanol-water (1:1) affords a ruthenium(III) complex, [Ru(pyca)3].H2O 1, and a diruthenium(II) compound, [Ru2(pyca)4] 2. The reaction of both complexes with PPh3 leads to the new compound [Ru(pyca)2(PPh3)2].2MeOH 3. The crystal structures of 1 and 3 have been determined. Crystals of both are monoclinic: 1, space group C2/c, a = 30.415(7), b = 8.506(1), c = 13.943(3) angstrom, beta = 94.55(2)-degrees, Z = 8; 3, space group P2(1)/n, a = 9.578(1), b = 20.540(3), c = 11.501 (2) angstrom, beta = 98.57(1)-degrees, Z = 2. Compound 1 consists of Ru(pyca)3 units linked by water molecules; the ruthenium environment is pseudo-octahedral with the ligands giving a mer arrangement. Compound 3 shows a trans disposition for the phosphine ligands with the pyridine-2-carboxylate ligands in the equatorial plane. In these complexes the pyridine-2-carboxylate ligands are co-ordinated in a bidentate mode through a carboxylate O atom and the pyridine nitrogen.