Tetrakis(pyridine)ruthenium Trans Complexes of Phenylcyanamide Ligands: Crystallography, Electronic Absorption Spectroscopy, and Cyclic Voltammetry

The complexes trans -[Ru(py) 4 L 2 ] where py = pyridine and L = (2-chlorophenyl)-, (2,3-dichlorophenyl)-, (2,4,5-trichlorophenyl)-, (2,3,4,5-tetrachlorophenyl)- and (pentachlorophenyl)cyanamide were synthesized and characterized by electronic and 1 H NMR spectroscopies. A crystal structure of trans -[Ru(py) 4 ((2-chlorophenyl)cyanamide) 2 ] showed the expected trans coordination of the phenylcyanamide ligands. Crystal structure data: space group C 2/ c, with a, b, and c = 40.6441(3), 9.2003(1), and 22.6946(2) Å, respectively, β = 116.387(1)°, V = 7602.2(1) Å 3, and Z = 8. The structure was refined by using 4943 independent reflections with I > 2σ( I ) to a final R factor of 0.060. Spectroelectrochemistry was used to generate the electronic absorption spectra of the Ru(III) complexes trans -[Ru(py) 4 L 2 ] + . Ru(III)−cyanamide coupling elements derived from charge transfer spectral data of the trans -[Ru(py) 4 L 2 ] + complexes were significantly larger than those of the corresponding [Ru(NH 3 ) 5 L] 2+ complexes.