Reaction of tetraacetatochlorodiruthenium(II,III) with pyridine-2-carboxylic acid. X-Ray crystal structures of tris(pyridine-2-carboxylato-κN,O)ruthenium(III) monohydrate and trans-bis(pyridine-2-carboxylato-κN,O)bis(triphenylphosphine)ruthenium(II)–methanol(1/2)

Abstract

The reaction of [Ru₂Cl(µ-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)Å, β= 94.55(2)°, Z= 8; 3, space group P2₁/n, a= 9.578(1), b= 20.540(3), c= 11.501(2)Å, β= 98.57(1)°, 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.