Preparation and characterization of cis- and trans-[Ru(OAc)(2mqn)2NO] (OAc=acetate, 2mqn=2-methyl-8-quinolinolate), and their mutual photoisomerization reactions

Abstract A mixture of hydrated nitrosylruthenium(III) chloride and 2-methyl-8-quinolinol (H2mqu) (1:4 molar ratio) in acetic acid aqueous solution adjusted to pH 5.5 and warmed at c . 70 °C for 2 h led to preparation of cis - [Ru(OAc)(2mqn) 2 NO] which has cis (0,0) and trans (N,N) configuration for the ligating atoms of the 2mqn ligands. The trans isomer was photochemically prepared from the cis isomer in CH 2 Cl 2 using an Xe lamp as the light source. The photoisomerization in deaerated CH 2 Br 2 was examined at −5 to 30 °C using a super high-pressure Hg lamp (436 mm). Quantum yields of the cis to trans and the trans to cis isomerizations were 1–2.5×10 −3 and 8–11×10 −3 , respectively. Solvent effect studies by adding liquid paraffin to the CH 2 Br 2 solution on the photoreaction and the NO scramble on the irradiation in the presence of 15 NO gas showed that RuNO bond rupture takes part in the isomerization.