A nitric oxide releaser based on the μ-oxo-hexaacetate-bis(4-methylpyridine)triruthenium nitrosyl complex

The properties of the trinuclear cluster [Ru3OAc6(pic)2(NO)]PF6 (pic = 4-methyl pyridine, Ac = acetate ion) and the photochemical behavior of the corresponding molecular films are reported in this paper. In this compound, the unpaired π* electron from NO and the unpaired electron from the π-orbitals of the Ru3O unity are strongly coupled; as a consequence, the changes in electronic distribution associated with the several successive redox states promote dramatic effects in the spectroscopic and electrochemical properties of the nitric oxide ligand and the entire complex. NO release has been observed by light irradiation (ϕ = 0.038 at 365 nm and ϕ = 0.019 at 468 nm, in acetonitrile solution), changing the original violet color into deep blue. The same behavior has been observed in solid state and in PVA films incorporating this compound, revealing its potential usefulness as NO photoreleaser, as well as for the monitoration of light exposure intensities.