Reactions of Azides Coordinated to Ruthenium(II) Centers with Haloalkanes To Afford Nitrogen-Containing Moieties

The reactions of azide ions coordinated to ruthenium(II) centers bearing two 2,2-bipyridine (bpy) ligands, that is, [Ru-II(N-3)(2)(bpy)(2)] (1), [Ru-II(N-3)(NH=CHR1)(bpy)(2)](+) (2; R-1 = CH3, C2H5), and [Ru-II(N-3)(NCCH3)(bpy)(2)](+) (3), with haloalkanes (CRRRX)-R-1-R-2-X-3 (R-1 = H, CH3, C2H5, R-2 = H, CH3, R-3 = H, CH3, X = I, Br) afforded imine (NH=(CRR2)-R-1) and ammine (NH3) ligands with dinitrogen evolution. The formation of these nitrogen-containing moieties depended on both the reaction solvent and the alkyl group of the haloalkane. Four types of imine complexes, [(RuL)-L-II(NH=(CRR2)-R-1)(bpy)(2)](n+) [L = N-3(-) (2), I- (4), NH=CHR1 (5), and CH3CN (6)], were synthesized and characterized. The oxidation reactions of the imine complexes 5 and 6 followed by electron- and proton-transfer reactions to give nitrile complexes were studied by electrochemical measurements. These results revealed new strategies for the synthesis of N-C bonds and nitrogen-containing compounds through the reactions of azido and related ligands.