Dependence of the Ru(III)-cyanamide chromophore on inner-sphere coordination: Comparison of cis-[Ru(bpy)2(pcyd)2]+ and [Ru(NH3)5(pcyd)]2+ complexes
Six bis(bipyridine)ruthenium(II) complexes of chloro-substituted phenylcyanamide anion ligands cis-[Ru(bpy)2(L)2], where L = monoanions of phenylcyanamide (pcyd), (2-chlorophenyl)cyanamide (2-Cl-pcyd), (2,3-dichlorophenyl)cyanamide (2,3-Cl2pcyd) (2,4,5-trichloro-phenyl)cyanamide (2,4,5-Cl3pcyd), (2,3,4,5-tetrachlorophenyl)cyanamide (2,3,4,5-Cl4pcyd) and (pentachlorophenyl)cyanamide (Cl5pcyd), have been synthesized and characterized by elemental analysis, 1H-NMR, IR, and UV-vis near-IR spectroscopies, and cyclic voltammetry. Oxidation of the complexes by controlled-potential electrolysis generated cis-[Ru(bpy)2(L)2]+. These Ru(III) complexes possess low-energy ligand to metal charge-transfer bands that are associated with the Ru(III)-NCN chromophore. A spectroscopic analysis of these LMCT transitions, which assumed C2v microsymmetry about Ru(III), determined their electronic origins. Differences between the properties of [Ru(NH3)5L]2+ and [Ru(bpy)2(L)2]+ complexes suggest that for the latter the covalency of the Ru(III)-NCN π bond has significantly increased.
Rezvani, A.R. (Ali R.), & Crutchley, R. (1994). Dependence of the Ru(III)-cyanamide chromophore on inner-sphere coordination: Comparison of cis-[Ru(bpy)2(pcyd)2]+ and [Ru(NH3)5(pcyd)]2+ complexes. Inorganic Chemistry, 33(1), 170–174.