Complexation and Oxidation of Glycine and Related Compounds by Ag(II)

Article abstract of DOI:10.1021/ja00544a021

The oxidation of glycine, several other amino acids, and carboxylic acids by Ag(II) has been studied.Transient spectra, kinetics, and product analysis indicate that the mechanism involves two steps.The first step is formation of a complex between Ag(II) and the substrate.The second step is an electron transfer from the carboxyl group to the Ag(II) within the complex.As a result, the substrate undergoes decarboxylation.The rate constants for complexation and oxidation were determined for a variety of substrates and with different forms of Ag(II), i.e., aquo, hydroxo, and ammino complexes.Both steps of the mechanism are affected by the structure of the substrate, for example, by the electron-donating properties of methyl groups and electron withdrawing by the NH3⁺ group.The rate of electron transfer within the complex is also affected by the structure and stability of the complex.The rate constants for complexation of the compounds studied under various conditions range from 10⁶ to 10⁸ M^-1 s^-1.The rates of oxidation were usually of the order of 10³ s^-1, although the highly stable complexes reacted more slowly.