Measuring the Correlation Times of Molecules Bound to Chiral Molecular Micelles
NMR spectroscopy was used to determine the correlation times of 1,1'- binaphthyl-2,2'-diyl hydrogen phosphate (BNP) protons when bound to molecular micelles. These molecular micelles contained a dipeptide head group composed of various amino acids. BNP is a chiral molecule and therefore contains both (R) and (S) enantiomers. The chiral analyte interacted with the chiral head group of the polymers by inserting into a chiral pocket. This chiral pocket, depending on which amino acids were contained in the head group, bound the BNP’s protons in a way to cause various degrees of anisotropy in the correlation times. This anisotropy was then correlated to the degree to which the polymer could discriminate between the two enantiomers. It was found that large degrees of anisotropy were characteristic of high chiral resolution and vice versa.