Preparation and Characterization of Tow kinds of cis-[RuCl(qn)2NO] (Hqn = 4-Methyl-, 2,4-dimetyl-, 2-ethly-, or 5-chloro-8-quinolinol), and the Photoinduced Preparation of the trans-[RuCl(qn)2NO] from the cis-Complex

A mixture of hydrous trichloronitrosylruthenium(III) and 8-qulinolinol derivative (4-methyl-, 2,4-dimethyl-, 2-ethyl-, or 5-chloro-8-quinolinol) (mole ratio 1 : 4—5) was refluxed in ethyl alcohol in the dark to prepare two kinds of cis-type complexes, [RuCl(qn)2NO] (Hqn = 8–quinolinol derivative), cis-1 and cis-2, as major products. Using 2,4-dimethyl- or 2-ethyl-8-quinolinol, the trans complex was prepared in low yield with the cis-type complexes. The trans complex could be photochemically generated from the cis-1 complex in dichloromethane in good yield. The introduction of an alkyl group with an electrondonating nature to the 2-position in the quinolinol ring could induce the formation of the trans complex. The complexes were characterized by NMR, IR UV-vis, and field desorption mass spectrometries. From the cis-1-trans photoisomerization reaction in the presence of 15NO (15N atom % = 99), a bond rupture between Ru and NO was found to be involved in the reaction.