Reaction of hydrous nitrosylruthenium trichloride with 2-pyridinemethanol

The reaction of hydrous nitrosylruthenium trichloride with an excess of 2-pyridinemethanol (H2pm) in boiling ethyl alcohol gave [H(2)2pm][RuCl3(2pm)NO] (H(2)2pm=the proton adduct of H2pm, 2pm =2-pyridinemethanolate ion) (1) and [RuCl2(2pm)(H2pm)NO] (2). [RuCl(2pm)(2)NO] (3) was isolated by heating complex 2 in boiling water. The reaction of hydrous nitrosylruthenium trichloride with an excess of H2pm in boiling water gave a slight amount of complex 4, a geometrical isomer of 3, together with 2 and 3. Na[RuCl3(2pm)NO]. H2O (5) was prepared from 1 by an anion-exchange chromatography. The complexes obtained were (Ru(II)-NO+} type octahedral complexes. The structures of 1, 2 and 3 were determined by X-ray crystal analysis. The alcoholato oxygen of 2pm in 1, 2 or 4 coordinates trans to the NO. For [RuCl3(2pm)NO] in 1, the three Cl atoms are cis to the NO. For 2, the ligating N atom of the H2pm is trans to the N atom of the 2pm. For 4, the Cl atom is cis to the NO and the geometry of the ligating N and O atoms of the two 2pm is in cis(N,N) and cis(O,O) configuration. The proton NMR spectra showed that, for 3, the Cl atom is cis to the NO and the geometry of the ligating N and O atoms of the two 2pm is in trans(N,N) and cis(O,O) configuration and the structure of the complex anion in 5 is the same as that in 1. In 1, a strong interaction between [H(2)2pm](+) and [RuCl3(2pm)NO](-) through the proton of [H(2)2pm](+) was observed in the solid state and reflected on the electric conductivity in DMF. The protonations to 2 and 3 were observed in the aqueous solution. Changes of 2 to 3 at 373 K and of 3 to 2 in the presence of DCl at room temperature were observed in DMSO. (C) 1999 Elsevier Science S.A. All rights reserved.