Cu Elimination from Cu-Coordinating Macromolecules

We demonstrate a simple, fast, and efficient process for the elimination of Cu impurities from water-soluble Cu-coordinating macromolecules that are difficult to purify via standard polymer purification techniques. The process is based on the complexation and precipitation of Cu by sodium diethyldithiocarbamate and was investigated for two different compound classes known to coordinate to Cu in aqueous solution. More than 99.9% of the Cu impurity was eliminated, with a remaining level below the detection limit (0.0005 wt %). Further analysis by 1H NMR, MALDI, ATR-IR, and SEC showed no degradation or side reactions of the polymers induced by the treatment. This process thus compliments the growing toolbox of Cu-catalyzed conjugation techniques as a mild, effective, and scalable tool for the removal of Cu from water-soluble and Cu-coordinating polymers.