Ruthenium Complexes of the Scorpionate Ligand Bis(3,5‐dimethylpyrazol‐1‐yl)dithioacetate and the Effect of Nitric Oxide Coordination

Six new ruthenium( II ) complexes with the scorpionateligand bis(3,5‐dimethylpyrazol‐1‐yl)dithio‐κ 3 N , N , S ‐acetate (bdmpzdta) were obtained by treatment of the ligand with RuCl 3 or [RuCl 3 (NO)] in 1:1 or 2:1 molar ratios in the presence or absence of ethylenediamine. In all six complexes the pyrazolic rings lie in the equatorial plane. The mononitrosyl complexes present a sharp ν(NO) band in the range 1864–1859 cm –1 for samples prepared either as KBr tablets or dichloromethane solutions. In the case of [Ru(NO)(bdmpzdta) 2 ]Cl ( 7 ), the dithiocarboxylate group of one of the ligands is not coordinated (κ 2 N , N ). In the other five complexes, however, bdmpzdta behaves as a κ 3 N , N , S scorpionate ligand. When the complexes obtained from RuCl 3 were dissolved in dichloromethane and NO was bubbled through the solution, a high degree of coordination of NO + was observed, according to IR, UV and voltammetric studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)