Spectroscopic determination of pKa’s in glycine-metal complexes under protic solvent conditions

α-Amino acids have proven useful in diverse industries including but not limited to food, materials, pharmaceuticals, chemical catalysis, and agriculture. Despite numerous schemes for the preparation of specific series of α-amino acids in the literature, the development of a general method for their synthesis remains a challenge. Of the methods in the literature, the application of nucleophilic glycine equivalents has shown promise. While there have been several modifications of the ligand system employed by this method, recent work has included the integration of various electron withdrawing groups to the ligand. These alterations have been hypothesized to increase the acidity of the C-H bond on the α-carbon of the glycine. This increased acidity could increase the generality and efficiency of the method by allowing milder reaction conditions. The work presented will provide an overview of method development and challenges of determining the pKa’s of the α-pro of a series of glycine metal complexes through UV-VIS spectrophotometric non-aqueous protic solvent conditions. In addition, the determined pKa’s in protic solvent conditions will be presented along with development of other spectroscopic methods of analysis.