Ruthenium(II) Complexes Bearing Carboxylato and 2‐Oxocarboxylato Ligands

Abstract

AbstractThe syntheses of ruthenium(II) acetato and benzoato complexes [Ru(bdmpza)(O2CCH3)(PPh3)] (6) and [Ru(bdmpza)(O2CPh)(PPh3)] (7) [bdmpza = bis(3,5‐dimethylpyrazol‐1‐yl)acetate] are reported. The complexes 6 and 7 are synthesized in high yield from [Ru(bdmpza)Cl(PPh3)2] (1) and thallium acetate (2) or thallium benzoate (3). In a similar substitution reaction a benzoylformate complex [Ru(bdmpza){O2CC(O)Ph}(PPh3)] (8) is obtained from 1 and thallium benzoylformate (4). Reaction of 6 or 7 with benzoylformic acid also yields 8. In analogous reactions several 2‐oxocarboxylato ruthenium(II) complexes [Ru(bdmpza){O2CC(O)R}(PPh3)] (9: R = CH2CH2CO2H, 10: R = Me, 11: R = Et) can be obtained. The low‐spin ruthenium(II) complexes 8 to 11 exhibit a purple or brownish‐red colour caused by MLCT transitions and thus a HOMO−LUMO gap which is almost identical to that of high‐spin 2‐oxoglutarate dependent iron oxygenases. 6 crystallises as a water adduct, 6·H2O and 8 forms an acetonitrile adduct 12. Crystal structures of the water adduct 6·H2O and 8 were obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)