An easy electrochemical and chemical synthesis of [Ru(bpy)(CH(3)CN)(2)Cl(2)]: a synthon for heteroleptic tris(diimine) Ru(ii) complexes.

A novel approach for the synthesis of heteroleptic tris(diimine) ruthenium complexes is reported. This strategy is based on the electrochemical or chemical reduction of Ru(iii) precursor complexes in MeCN such as [Ru(bpy)(X)Cl(3)] (bpy = 2,2'-bipyridine; X = MeCN () or MeOH ()). This method allows the preparation with high yield of the highly valuable [Ru(bpy)(MeCN)(2)Cl(2)] synthon (). The full characterization (mass spectrometry, (1)H NMR, absorption spectroscopy and electrochemistry) of [Ru(bpy)(MeCN)(2)Cl(2)] as a pure compound is reported for the first time. Indeed the later was previously only obtained in mixtures with the corresponding tris(acetonitrile) derivative: [Ru(bpy)(MeCN)(3)Cl]Cl. (1)H NMR analysis of indicates that its structure corresponds to the cis(Cl)-cis(MeCN) isomer form. [Ru(bpy)(MeCN)(2)Cl(2)] has been further used to synthesize [Ru(bpy)(Me(2)bpy)Cl(2)] (Me(2)bpy = 4,4'-dimethyl-2,2'-bipyridine) for which X-ray analysis indicates that the two chloride ligands are also in cis position.