Effect of conjugation on the oscillator strength of the ruthenium(III)-cyanamide chromophore
The complexes, [(NH3)5Ru(L)][ClO4]2, where L− = cyanamide, phenylcyanamide, 4-cyanamidobiphenyl, 1-cyanamidonaphthalene, 2-cyanamidonaphthalene, 2-cyanamidophenanthrene, and 1-cyanamidopyrene anions, were synthesized and characterized by cyclic voltammetry and electronic absorption spectroscopy. The Ru(III/ II) couple was shown to shift positively with increasing conjugation of the group attached to the cyanamide moiety and indicated withdrawal of cyanamide electron density onto the conjugated group. Extended Hueckel calculations of the free anion ligands permitted estimates of transition dipole moment lengths, R, for the b1 * ← b1 transition of the cyanamide complexes. Only an approximate positive correlation was shown between oscillator strength and R2.
Evans, C.E.B. (Christopher E. B.), Ducharme, D. (Dean), Naklicki, M.L. (Mark L.), & Crutchley, R. (1995). Effect of conjugation on the oscillator strength of the ruthenium(III)-cyanamide chromophore. Inorganic Chemistry, 34(6), 1350–1354.