Ruthenium(II) complexes containing 2-diphenylphosphinobenzaldehyde: synthesis and catalytic activity in transfer hydrogenation§

The reaction of dimers [Ru(η6-arene)(μ-Cl)Cl]2 (arene=C6H6 (2a); 1-iPr-4-C6H4Me (2b); 1,2,4,5-C6H2Me4 (2c); C6Me6 (2d)) with 2-diphenylphosphinobenzaldehyde (1) yields the neutral complexes [Ru(η6-arene)Cl2(κ1-P-2-Ph2PC6H4CHO)] (3a–d). Treatment of compounds 3a–d with one equivalent of AgSbF6 leads to the formation of the monocationic derivatives [Ru(η6-arene)Cl(κ2-P,O-2-Ph2PC6H4CHO)][SbF6] (4a–d). When 3a–d are treated with two equivalents of AgSbF6 in presence of acetone, the dicationic complexes [Ru(η6-arene)(κ1-O-Me2CO)(κ2-P,O-2-Ph2PC6H4CHO)][SbF6]2 (arene=C6H6 (5a); 1-iPr-4-C6H4Me (5b); 1,2,4,5-C6H2Me4 (5c); C6Me6 (5d)) are obtained. Complexes 3–5a–d have proven to be active catalysts in transfer hydrogenation of acetophenone by propan-2-ol.