Photoirradiation reactions and crystal structures of two geometrical isomers of [Ru(OAc)(2cqn)2NO] (H2cqn=2-chloro-8-quinolinol)

The photoirradiation reactions of two geometrical isomers (cis-1 and cis-2) of [Ru(OAc)(2cqn)2NO] (H2cqn=2-chloro-8-quinolinol) were studied. Cis-2 [Ru(OAc)(2cqn)2NO] (2) photochemically isomerized to cis-1 [Ru(OAc)(2cqn)2NO] (1) in CH2Cl2 or DMSO using an Xe lamp as a light source and the reaction was irreversible. The 2 to 1 isomerization coexisting with 15NO gas and its evolution of the 1H NMR spectra showed that the dissociation and recombination of both the NO and the acetate ion involve in the isomerization. On the other hand, 1 did not isomerize but the NO ligand exchanged with 15NO. The crystal structures of 1 and 2 were determined by X-ray diffraction.