Synthesis, structure and redox properties of ruthenium complexes containing the tpm facial and the trpy meridional tridentate ligands -: Crystal structures of [RuCl3(trpy)] and [Ru(tpm)(py)3](PF6)2

A new and convenient route for preparation of [Ru(trpy)(H2O)(3)](2+) involving reductive cleavage of the corresponding oxo dimers has been established. Furthermore, new complexes bearing the tridentate facial ligand tpm (tris(1-pyrazolyl)methane) and the tridentate meridional ligand trpy (2,2':6',2"-terpyridine) have been prepared from the corresponding [(RuL)-L-II(H2O)(3)](2+) (L = tpm, trpy) precursors, The complexes obtained with general formula [(RuLL)-L-II'](2+) (L = tpm, L' = py(3), py(2)H(2)O; L = trpy, L' = trpy, py(3), Cl-3) have been spectroscopically and electrochemically characterised and the structure of [Ru(tpm)(py)(3)](PF6)(2) and of [RuCl3(trpy)] determined by means of X-ray crystallography. (C) 1999 Elsevier Science Ltd, All rights reserved.