Abstract
The coordination chemistry of Ru^II^ ions with [2โ(diphenylphosphanyl)โNโ(oโhydroxybenzylidene)]aniline (PNOโH) and the methylated analogue PNOโMe have been studied. Thus, [(PNO)RuCl(dmso)~2~] (1), [(PNO)~2~Ru] (2), [(PNO)RuCl(PPh~3~)] (3) and [(PNO)RuCl(CO)~2~] (4) were synthesized by reactions of various Ru^II^ precursors with PNOโH. Treatment of PNOโMe with [RuCl~2~(dmso)~4~] resulted in in the formation of [P,Nโ(PNOโMe)Ru(dmso)~2~Cl~2~] (5). However, complexation of PNOโMe with [RuCl~2~(CO)~3~(THF)] (THF = tetrahydrofuran) provided a mixture of [P,Nโ(PNOโMe)Ru(CO)~2~Cl~2~] (6) and 4 because Oโdemethylation took place during the reaction. All of the Ru^II^ complexes have been characterized by elemental analysis and spectroscopic techniques, as well as Xโray crystal structural analysis for 2, 4 and 6. The ruthenium complexes investigated in this work, except 2, are good precatalysts for the reductive amination of amine with alcohols, and 4 appears to be the best. Moreover, 4 can catalyze the direct amination of nitrobenzene with benzyl alcohol to the corresponding secondary amine.