Chiral NMR Shift Reagents

Bates College, Lewiston ME

Investigators

Abstract

This project, conducted by Dr. Thomas J. Wenzel and undergraduate students at Bates College, is supported in the Analytical and Surface Chemistry program. The research, which is a part of NSF's Research in Undergraduate Institutions (RUI) initiative, develops and utilizes combinations of chiral NMR shift reagents to resolve mixtures of enantiomeric substrates. The chiral component of the shift reagents includes calixarenes, calixresorcarenes, crown ethers, cyclodexrins and amino acid derivatives. Paramagnetic lanthanide ions are coupled to the chiral solvating agents to achieve improved enantiomeric resolution in NMR applications. Information from 2D NMR, computational, x-ray crystallographic, and lanthanide shift and relaxation studies are used to determine if the mechanism that leads to enantiodistinction is specific enough to allow absolute configurations to be assigned. As new pharmaceuticals are being more quickly developed, improved techniques for differentiation of optical isomers become increasingly important . This research develops techniques to improve such differentiation. As a result it will help assure the efficacy and safety of many new pharmaceuticals.