Ruthenium(II) octaphenylporphyrazine complexes with mixed axial ligands: Peculiarities of their formation and spectral properties

A series of new axially bis-coordinated (octaphenylporphyrazinato)ruthenium(II) complexes {[(Ph(8)Pz)RuL2], L = cyclohexyl isocyanide, CyNC, (1b); 4,4'-bipyridine, bpy, (2c); N-methylimidazole, CH(3)Im, (3a)} was prepared and characterized. The reaction of the bis-isocyanide adducts [(Ph(8)Pz)Ru(tBuNC)(2)] (1a) or [(Ph(8)Pz)Ru(CyNC)(2)] (1b) with monodentate N-heterocycles gave, under certain conditions, the mixed-ligand complexes [(Ph(8)Pz)Ru(Py)(tBuNC)] (4a), [(Ph(8)Pz)Ru(Py)(CyNC)] (4b) and [(Ph(8)Pz)Ru(CH3IM)(CyNC)] (3b). The reaction of 1a or 1b with an excess of bidentate 4,4'-bipyridine under the same conditions resulted in the formation of the corresponding dimeric species [(Ph(8)Pz)Ru(tBuNC)](2)(mu-bpy) (2a) and [(Ph(8)Pz)Ru(CyNC)](2)(mu-bpy) (2b) in high yield. The structures of all the complexes were unambiguously proved by H-1 NMR spectroscopy, and the possibility of their self-assembly is discussed. All mixed-ligand compounds were also characterized by UV/Vis and IR spectroscopy, as well as elemental analysis. The H-1 NMR spectra of these compounds are discussed in detail. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.