Determination of Solubility Limits for PDTC and Cu[PDTC]Br

Abstract

Carbon tetrachloride (CCl4) is an organic compound that once widely used as an industrial solvent, degreaser, and grain fumigant.  Improper disposal and ground water solubility issues led to CCl4 being listed as a priority pollutant by the U.S. EPA. We are currently investigating the use of 2,6-pyridinedithiocarboxylic (PDTC) and its copper coordination compound [Cu(PDTC)L]x as a potential CCl4 environmental remediation technology.  PDTC and Cu[PDTC]Cl have a very low solubility in water, which decreases the effectiveness of the molecule as a remediation technique.  Using a ligated iron UV-Vis spectroscopy assay PDTC’s solubility was determined to be 39 mM in a pH 7.6 (check this number) buffer. The solubility of Cu(PDTC)Br in pH 7.6 buffer was determined to be 50 mM via oversaturation UV-VIS assay. The results from both solubility studies were used to confirm a high throughput assay based on dynamic light scattering.  The solubilities determined in this study will act as an initial benchmark for the comparison of future novel PDTC derivatives.