960253-66-1Relevant academic research and scientific papers
Hydrogenation of benzonitrile to benzylamine catalyzed by ruthenium hydride complexes with P-NH-NH-P tetradentate ligands: Evidence for a hydridic-protonic outer sphere mechanism
Li, Tianshu,Bergner, Ines,Haque, F. Nipa,Iuliis, Marco Zimmer-De,Song, Datong,Morris, Robert H.
, p. 5940 - 5949 (2007)
The reaction of RuHCl(PPh3)3 with the tetradentate ligand [PPh2((ortho-C6H4)CH 2NHCH2-)]2 {ethP2 - (NH)2} in THF produces the new complex trans-RuHCl{ethP2(NH)2} (1) as a mixture of two isomers. The complex RuHCl{ethP2(NH)2} (1) when activated with KOtBu/KH is a very active catalyst for the hydrogenation of benzonitrile to benzylamine in toluene, more active than the known catalyst Ru(H2)2H2- (PCy3) 2 (2). A mixture of 1 and 2 and base also results in efficient conversion of benzonitrile to benzylamine. The complex RuHCl{tmeP 2(NH)2} (3) where tmeP2(NH)2 is [PPh2((ortho-C6H4)CH2- NHCMe2-)]2 is a less active catalyst for this reaction. These catalyst systems are air sensitive and extremely moisture sensitive. Experimental and theoretical (DFT) evidence is presented for a new mechanism for nitrile hydrogenation: the successive hydrogenation of the CN triple bond and then the CN double bond of the intermediate imine by H +/H- transfer from a trans dihydride active catalyst. The amido complex RuH{tmeP2N(NH)} (4) has similar activity to 3/base for the base-free hydrogenation of benzonitrile and is moderately active for the catalytic hydration of benzonitrile. The new complex RuH(BH4) {ethP2- (NH)2} (7) was prepared by reacting 1 with NaBH4 but is found to be a poor catalyst for nitrile hydration.
