Aqueous organometallic catalysis. Isotope exchange reactions in H2–D2O and D2–H2O systems catalyzed by water-soluble Rh- and Ru-phosphine complexes

Abstract

The water-soluble complexes [{RuCl₂(mTPPMS)₂}₂], [RuCl₂(PTA)₄], [RhCl(mTPPMS)₃], [RhCl(mTPPTS)₃], and [RhCl(PTA)₃] (mTPPMS = sodium salt of meta-sulfonatophenyl-diphenylphosphine, mTPPTS = sodium salt oftris(meta-sulfonatophenyl)phosphine, and PTA = 1,3,5-triaza-7-phosphaadamantane) showed high catalytic activity (up to 1252 h⁻¹) in the H–D isotope exchange reactions between H₂ and D₂O or D₂ and H₂O. The reactions took place at 20–70 °C, 0.1–2 MPa H₂, and were strongly influenced by the pH. In the hydrogenation (with H₂) of unsaturated acids in D₂O, the relative rates of H–D exchange, hydrogenation and deuteration were determined by the individual substrates and catalysts: in the reaction of maleic acid catalyzed by [RhCl(mTPPMS)₃] only hydrogenation took place with no deuteration and H–D exchange, whereas a similar reaction of itaconic acid was accompanied by a fast H–D exchange and the product methylsuccinic acid was highly deuterated.