Synthesis, characterization and reactivity of arene ruthenium compounds based on 2,2 '-dipyridylamine and di-2-pyridylbenzylamine and their applications in catalytic hydrogen transfer of ketones

The synthesis and characterization of cationic arene ruthenium compounds [(eta(6)-p-(PrC6H4Me)-Pr-i)RuCl(kappa(2)-dpa)]BF4 (1), [(eta(6)-C6H6)RuCl(kappa(2)-dpa)]BF4 (2), [(eta(6)-p-iPrC(6)H(4)Me)-RuCl(kappa(2)-dpb)]BF4 (3), [(eta(6)-p-(PrC6H4Me)-Pr-i)RuCl(kappa(2)-dpb)]PF6 center dot CH3OH (4) and [(eta(6)-C6H6)-RuCl(kappa(2)-dpb)]PF6 (5) (arene C6H6 or p-(PrC6H4Me)-Pr-i; dpa = 2,2'-dipyridylamine and dpb = di-2-pyridylbenzylamine) have been described. Reactions of the representative compounds 1 and 3 with NaN3, NaCN, and NH4SCN afforded substitution products [(eta(6)-p-(PrC6H4Me)-Pr-i)-Ru(kappa(2)-dpa)(N-3)] BF4 (6), [(eta(6)-p-(PrC6H4Me)-Pr-i)Ru(kappa(2)-dpa)(CN)]BF4 (7), [(eta(6)-p-(PrC6H4Me)-Pr-i)-Ru(kappa(2)-dpa)(NCS)]BF4 (8), [(eta(6)-p-(PrC6H4Me)-Pr-i) Ru(kappa(2)-dpb)(N-3)]BF4 (9), [(eta(6)-p-iPrC(6)H(4)Me)-Ru(kappa(2)-dpb)(CN)]BF4 (10) and [(eta(6)-p-iPrC(6)H(4)Me)Ru(kappa(2)-dpb)(NCS)]BF4 (11). The compounds under investigation have been characterized by elemental analyses, spectroscopic and electrochemical studies. Molecular structures of 1, 3, 4 and 5 have been determined crystallographically. The compounds 1-3 and 5 exhibited moderate catalytic activity in the reduction of ketones into corresponding alcohol in absence of a base. (C) 2010 Elsevier B. V. All rights reserved.