The Catalytic Conversion of Parahydrogen by Paramagnetic Complex Ions in Aqueous Solution

Rates of conversion of parahydrogen by paramagnetic complex ions of copper (II) and chromium (III) in aqueous solution have been measured at 25°C. The results are discussed in terms of the Wigner theory, which predicts the effects of magnetic moment and collision distance. Owing to the planar configuration of the copper (II) complexes, only a qualitative test of theoretical predictions is possible. The rate effects produced by various symmetrical octahedral complexes of chromium (III) can be explained in terms of the theory if one evaluates the various collision distances for H2 from a detailed examination of the complex structure in each case.