Four novel phosphine-substituted ruthenium(ii) polypyridine complexes with nitrogen oxides-trans(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (trans-NO2), cis(P,NO2)-[Ru(trpy)(Pqn)(NO2)]PF6 (cis-NO2), [Ru(trpy)(dppbz)(NO2)]PF6 (PP-NO2), and cis(P,NO)-[Ru(trpy)(Pqn)(NO)](PF6)3 (cis-NO)-were synthesised (trpy = 2,2':6',2''-terpyridine, Pqn = 8-(diphenylphosphanyl)quinoline, and dppbz = 1,2-bis(diphenylphosphanyl)benzene). The influence of the number and position of the phosphine group(s) on the electronic structure of these complexes was investigated using single-crystal X-ray structural analysis, UV-vis absorption spectroscopy, and electrochemical measurements. The substitution lability of the nitrogen oxide ligand of each complex is discussed in comparison with that of the corresponding acetonitrile complexes.

This research presents the synthesis and characterization of the photochemical nitric oxide (NO) precursor Ru(salenCO2H)(NO)Cl (I, salenCO2H = N,. This water-soluble ruthenium nitrosyl releases NO upon photolysis with a quantum yield that is pH dependent owing to the nitrosyl to nitrite conversion of that axial ligand at higher pH. Also described are the water, oxygen, and thermal stability of I and the cytotoxicity and the vascular relaxivity properties of I in the dark and under photolysis.