Selective Deoxygenation of Various N–O Bonds Catalyzed by Rhodium Carbonyl Clusters in the Presence of H2O and CO and Their Heterogenization Using Amino-Substituted Polystyrenes

Catalytic deoxygenation of various N–O bonds using rhodium carbonyl compounds under a water gas shift reaction was studied. A catalyst system of Rh6(CO)16 and N,N,N′,N′-tetramethyl-1,3-propanediamine was found to have high activities for the following deoxygenations: 1) conversion of nitrobenzenes to anilines, 2) aliphatic nitro compounds to nitriles, 3) oximes to nitriles, 4) hydroxylamines to amines, and 5) amine oxides to amines. The above-mentioned rhodium catalyst system was heterogenized by using amino-substituted polystyrenes. Rh6 and Rh14 carbonyl clusters of [Rh6(CO)15H]−, [Rh6(CO)15]2−, and [Rh14(CO)25]4−, were formed on the polymer surface. The characteristic features of the catalysis of the polymer-bound rhodium cluster complexes are described in relation to the corresponding homogeneous ones.