Solution and solid-state light-induced transformations in heterometallic vanadium-ruthenium nitrosyl complex

The work is devoted to the preparation and photochemical investigations of the novel binuclear heterometallic complex [Ru(NO)(NO2)(2)(mu-NO2)(mu-CH3COO)(mu-O)VO(dbbpy)]center dot CH3CN (dbbpy - 4,4'-di-tert-butyl-2,2'-bipyridyl), which is obtained with quantitative yield. The structure of the complex is determined by single crystal Xray diffraction and by DFT calculations. On the one hand, irradiation at 445 nm of an acetonitrile solution of the complex leads to a NO photo-release reaction. The light excitation induces the charge transfer from NO2 and dbbpy ligands to the antibonding orbitals of ON-Ru-O-V chain, leading to the NO release, which is confirmed by the DFT. The quantum yield of the Ru-NO photo-cleavage is 0.57 +/- 0.05 %. The products of the photolysis (NO and paramagnetic Ru m complex) are confirmed by the Griess test and EPR-spectroscopy. On the other hand, the irradiation of the complex in the solid phase at 10 K results in the formation of the metastable bond isomer RuON (MS1), which is detected by the infrared spectroscopy. The stretching vibration of the u(NO) band of MS1 (1750 cm(-1)) is shifted by 150 cm(-1) to lower energy with respect to the u(NO) band of the ground state GS (1900 cm(-1)). The population of the MS1 is about 5%. MS1 thermally decays at 120-140 K back to the GS. Hence, this complex represents a bifunctional platform, which can release nitric oxide in solution and reversibly switch the NO ligand coordination in the solid state. It is shown, that the presence of vanadium strongly influences the photochemical properties of ruthenium nitrosyl both in the solid phase and in solution.

Automated summary

This work focuses on the preparation and photochemical investigations of a novel binuclear heterometallic complex, which exhibits a bifunctional platform capable of releasing nitric oxide in solution and reversibly switching the NO ligand coordination in the solid state. The presence of vanadium strongly influences the photochemical properties of ruthenium nitrosyl in both solid and solution phases, as confirmed by various analytical techniques.