INTRAMOLECULAR AND INTERMOLECULAR HYDROGEN-BONDING IN TRIPHENYLPHOSPHINE DERIVATIVES OF COPPER(I) CARBOXYLATES, (PH(3)P)(2)CUO2C(CH2)(N)COOH - ROLE OF COPPER(I) IN THE DECARBOXYLATION OF MALONIC-ACID AND ITS DERIVATIVES Academic Article uri icon

abstract

  • The air-sensitive copper(I) hydrogen dicarboxylate complexes (Ph3P)2CuO2C(CH2)nCOOH (n = 1,2) and derivatives thereof have been synthesized from 1 equiv of the corresponding dicarboxylic acid and cuprous butyrate. The solid-state structures of these derivatives exhibit quite different hydrogen bonding motifs. That is, the malonate derivative (1) contains a three-coordinate copper(I) center composed of two phosphine ligands and a monodentate carboxylate ligand. The appended carboxylic acid forms a strong intramolecular hydrogen bond with the distal oxygen atom of the carboxylate group bound to copper. On the other hand, the succinate derivative (2) displays a polymeric chain structure in which the carboxylic acid moiety is intermolecularly hydrogen bonded to the neighboring complex. Complex 1 undergoes decarboxylation in tetrahydrofuran solution, whereas complex 2 is stable toward decarboxylation. The phenylmalonic acid analog of complex 1 similarly undergoes carbon dioxide extrusion under milder conditions than 1 and has been shown to proceed via a first-order process. This copper(I) derivative is a very effective catalyst for the decarboxylation of phenylmalonic acid to phenylacetic acid and carbon dioxide. This process has been shown to be first-order in copper(I) complex and zero order in [acid]. The rate constants for CO2 extrusion from the complex and for acid decarboxylation are very similar, an observation consistent with a reaction pathway for the catalytic decarboxylation where the slow step is the extrusion of CO2 from the half-acid copper(I) complex. The role of intra- and intermolecular hydrogen bonding involving complex 1 on the CO2 extrusion process isdiscussed. Crystal data for 1: space group P1, a = 12.949(6) , b= 13.162(7) , c= 13.253(6) , = 60.73(3), = 85.26(4), = 68.62(4), Z= 2, R = 5.80%. Crystal data for 2: space group P21/n, a = 13.141(2) , b = 13.0070(10) , c = 20.814(3) , = 100.300(10), Z = 4, R = 4.00%. 1994, American Chemical Society. All rights reserved.

published proceedings

  • INORGANIC CHEMISTRY

author list (cited authors)

  • DARENSBOURG, D. J., HOLTCAMP, M. W., KHANDELWAL, B., & REIBENSPIES, J. H.

citation count

  • 37

complete list of authors

  • DARENSBOURG, DJ||HOLTCAMP, MW||KHANDELWAL, B||REIBENSPIES, JH

publication date

  • February 1994