Effect of Hydrogen-Bonding in the Development of High-Affinity Metal Ion Complexants: Polymer-Bound Phosphorylated Cyclodextrin

In a series of phosphorylated polyols bound to a polystyrene support, the position of the FTIR band assigned to hydrogen bonding between the -OH and phosphoryl oxygen correlates with the affinity of that phosphoryl oxygen for metal ions. Polymer with phosphorylated beta-cyclodextrin (pCD) ligands is now reported as a further test of this correlation. The metal ion affinity is probed with the uranyl ion. pCD is the most red-shifted of a series of five phosphorylated polyols: the strongest polyol had been phosphorylated pentaerythritol (pPE) with a band at 873 cm(-1); pCD has a band at 868 cm(-1). Consistent with the FTIR bands, pCD has a significantly higher affinity for the uranyl ion than pPE: the percents complexed from a 10(-4)M uranyl solution in a background of 1.0N HNO3, HCl, and H2SO4 are 94.7%, 90.5%, and 93.6%, respectively, for pCD and 68.6%, 52.1%, and 40.1%, respectively, for pPE. This further supports the hypothesis that the strong complexing ability of phosphorylated polyols is due to activation of the phosphoryl oxygen through hydrogen bonding between the P = O and the -OH groups within the polyol. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 1137-1142, 2011