Isotopic effects of hydrogen in the dark and photochemical reaction of the pentacyanocobaltate(II) (cobaltocyanide) ion in aqueous solutions

Isotopic effects have been investigated at various stages during the reaction of the pentacyanocobaltate (cobaltocyanide) ion (PCC) with water, in photochemical and dark variants. It is found that the magnitudes of the kinetic isotopic effects of hydrogen do not exceed 1.5. The isotope composition of hydrogen liberated into the gas phase in the dark corresponds to the equilibrium value for an isotope exchange reaction between molecular hydrogen and water, but under photochemical conditions the deuterium content is less than the equilibrium value. It has been found that light considerably accelerates the isotope exchange reaction of PCC hydride with water. An explanation is given of the effects obtained