Neutral and cationic (eta(6)-arene)-ruthenium(II) complexes containing the iminophosphorane-phosphine ligand Ph2PCH2P(=N-p-C5F4N)Ph-2: influence of the arene ring in catalytic transfer hydrogenation of cyclohexanone

摘要

Ruthenium(11) dimers [{Ru(eta(6)-arene)(mu-Cl)Cl}(2)] (la-f) readily react with the iminophosphorane-phosphine ligand Ph2PCH2P(= N-p-C5F4N)Ph-2 (2), in dichloromethane at room temperature, to afford the neutral derivatives [RU(eta(6)-arene)Cl-2{k(1)-P-Ph2PCH2P(N-p-C5F4N)Ph-2}] (arene=C6H6 (3a), 1-'Pr-4-C6H4Me (3b), l,3,5-C6H3Me3 (3c), l,2,3,4-C6H2Me4 (3d), 1,2,4,5-C6H2Me4 (3e), C6Me6 (3f)). Treatment of 3a-f with AgSbF6 in dichloromethane yields the cationic species [Ru(eta(6)-arene)Cl{k(2-)P,N-Ph2PCH2P( N-p-C5F4N)Ph-2}][SbF6] (4a-f). The catalytic activity of complexes 3 and 4 in transfer hydrogenation of cyclohexanone by propan-2-ol has been studied. Among them, the cationic derivative [Ru(eta(6)-C6Me6)Cl{k(2)-P,N-Ph2PCH2P(=N-p-C5F4N)Ph-2}][SbF6] (4f) shows the highest activity. Electrochemical data for 3 and 4 are also reported. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 64]