Novel coincidence effects in a bimetallic phase transfer catalyzed reaction. Biphasic reduction reactions catalyzed by rhodium carbonylmetallate clusters

Bimetallic and cluster rhodium carbonyl complexes catalyze the biphasic reduction of nitro compounds under mild conditions (using CO/5 M NaOH, C₆H₆ or PhCH₃). Rate studies indicate the sensitivity of the reaction to the nature of the organic substrate, base concentration, and the temperature. A previously observed bimetallic (Co₂(CO)₈ and (1,5-HDRhCl)₂) and phase transfer catalyzed [R₄N⁺X⁻] reduction of nitro compounds was found to be a consequence of the inhibition and reactivation of the true catalyst by the quaternary ammonium salt and cobalt carbonyl, respectively.