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An in situ generated catalyst from readily available RuH(2)(PPh(3))(4), an N-heterocyclic carbene (NHC) precursor, NaH, and acetonitrile was developed. The catalyst showed high activity for the amide synthesis directly from either alcohols or aldehydes with amines. When a mixture of an alcohol and an aldehyde was reacted with an amine, both of the corresponding amides were obtained with good yields. Homogeneous Ru(0) complexes such as (eta(4)-1,5-cyclooctadiene)(eta(6)-1,3,5-cyclooctatriene)ruthenium [Ru(cod)(cot)] and Ru(3)(CO)(12) were also active in the amidation of an alcohol or an aldehyde with the help of an in situ generated NHC ligand.

The synthesis of a ruthenium complex bearing a PN-chelating ligand is described. The complex, in the presence of KOH, enabled the synthesis of ketones from secondary alcohols in the absence of a hydrogen acceptor in aqueous medium. This synthetic protocol, which uses water as the medium, is green and has a high atom economy as it avoids the use of an acceptor and produces hydrogen as the sole byproduct. Mechanistic investigations revealed that the catalytic cycle involves a phosphine dissociative pathway. [ABSTRACT FROM AUTHOR]

An efficient, operatively simple, acceptorless, and base-free dehydrogenation of secondary alcohols and nitrogen-containing heterocyclic compounds was achieved by using readily available ruthenium hydride complexes as precatalysts. The complex RuH2(CO)(PPh3)3 ( 1) and Shvo's complex ( 2) showed excellent activities for the dehydrogenation of secondary alcohols and nitrogen containing heterocycles. In addition to complexes 1 and 2, the complex RuH2(PPh3)4 ( 3) also showed moderate to excellent activity for the acceptorless dehydrogenation of nitrogen-containing heterocyclic compounds. Kinetic studies on the oxidation reaction of 1-phenylethanol using complex 1 were carried out in the presence and the absence of external triphenylphosphine (PPh3). External addition of PPh3 had a negative influence on the rate of the reaction, which suggested that dissociation of PPh3 occurred during the course of the reaction. Hydrogen was evolved from the oxidation reaction of 1-phenylethanol by using 1 mol% of 1 (88%) and 2 (92%), which demonstrated the possible usage of the catalytic systems in hydrogen generation. [ABSTRACT FROM AUTHOR]