Bis(allyl)-ruthenium() complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions

Several mononuclear ruthenium( iv ) complexes with phosphinous acid ligands [RuCl 2 ( 3 : 3 -C 10 H 16 )(PR 2 OH)] have been synthesized (7886% yield) by treatment of the dimeric precursor [{RuCl(-Cl)( 3 : 3 -C 10 H 16 )} 2 ] (C 10 H 16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R 2 P(&z.dbd;O)H. The compounds [RuCl 2 ( 3 : 3 -C 10 H 16 )(PR 2 OH)] could also be prepared, in similar yields, by hydrolysis of the PCl bond in the corresponding chlorophosphineRu( iv ) derivatives [RuCl 2 ( 3 : 3 -C 10 H 16 )(PR 2 Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl 2 ( 3 : 3 -C 10 H 16 )(PR 2 OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl 2 ( 3 : 3 -C 10 H 16 )(PMe 2 OH)], which proved to be active under mild conditions (60 C), with low metal loadings (1 mol%), and showing good functional group tolerance. The preparation of bis(allyl)-Ru( iv ) complexes with phosphinous acid ligands is presented, as well as their application as catalysts in the base-free hydration of organonitriles in water.