Ruthenium hydrogenation catalysts with P-N-N-P ligands derived from 1,3-diaminopropane and the formation of a beta-diiminate complex by a base-induced isomerization

摘要

The complexes RuHCl{PPh2(2-C6H4)CH=NCH2CH2CH2N=CH(2-C6H4) PPh2} (RuHCl{prP(2)N(2)}, 7) and RuHCl{PPh2(2-C6H4) CH2NHCH2CH2CH2NHCH2(2-C6H4)PPh2} (RuHCl{prP(2)(NH)(2)}, 8) are prepared by reaction of RuHCl(PPh3)(3) with a ligand derived from 1,3- diaminopropane and ortho-diphenylphosphinobenzaldehyde. They are active precatalysts for the hydrogenation of acetophenone and are moderately active for the hydrogenation of benzonitrile and imines. The related complex RuHCl{ethP(2)(NH)(2)} with a ligand derived from 1,2-diaminoethane provides a more active catalyst. Complexes 7 and 8 undergo an unusual base-promoted isomerization reaction that produces a ruthenium complex containing a novel beta-diiminato ligand. (c) 2007 Elsevier B.V. All rights reserved.