Homogeneous Catalysis of D2–H2O Isotope Exchange by Pentacyanocobaltate(II)

Abstract

The rate of exchange of deuterium between hydrogen gas and water catalyzed by pentacyanocobaltate(II) has been measured as a function of pressure and temperature at a constant total cobalt concentration, 0.05 M, and ionic strength, 1 M. The rates of evolution of hydrogen from solutions of hydridopentacyanocobaltate(III) have been determined under identical conditions. These data have been employed to test the validity of a mechanism for the[Formula: see text] -catalyzed isotope exchange reaction, and to clarify the controversy over the magnitude of the specific rate for the deuterium transfer step[Formula: see text]Calculations show that kinetic isotope and ion pairing effects are significant.