Preparation and photochemical properties of cyclometalated ruthenium(II) nitrosyl complexes

Complex 1 with 2-(4-methylphenyl)pyridine as C, N-ligand was used to react with NOBF4 under different conditions to afford two cyclometalated ruthenium(II) nitrosyl complexes 2 and 3 in high yields. Herein, increasing temperature and aerobic conditions were favored by the generation of 3. NMR, MS, IR, and single-crystal X-ray structure analysis showed that these two nitrosyl complexes have {Ru-II-NO+} characteristics. This was further confirmed by electrochemistry and UV-Vis absorption spectra. Subsequently, the photolyzed product of ruthenium nitrosyl complex 2 was separated and characterized by NMR and MS spectra. The result showed that such nitrosyl complexes could give a release of NO by the breakage of Ru-NO under the light, along with Ru(II) as the oxidation state.