The influence of hydroxide to fluoride substitution in the trans-position to NO on the photochemistry of ruthenium nitrosyl complexes in the solid state and in solution

Abstract

A new [RuNO(Py)₂Cl₂F] (1) complex with a trans NO–Ru–F coordinate was prepared by the reaction of HF and [RuNO(Py)₂Cl₂OH] (2). The photochemical properties of [RuNO(Py)₂Cl₂X] (X = F, OH) were compared in the solid state and in DMSO solution. In the solid state, blue-light irradiation produces isonitrosyl metastable linkage isomers (MS1) in both compounds. For [RuNO(Py)₂Cl₂OH], the formation of a side-on coordinated MS2 isomer was also detected after irradiation at 405 nm. The thermal stability of MS1 and MS2 was investigated using DSC, and the corresponding kinetic parameters (E_a and k₀) and characteristic decay temperature (T_d) were determined. The irradiation in DMSO solution results in NO release for both complexes, and the determined quantum yield for 2 is about four times higher compared to that of 1, which also correlates with higher conversion to MS1 and MS2 in the solid state.