Separation, Enantiorecognition, and Chiral Stationary Phase Design of Organophosphonates
Mechanistic investigations of several chiral stationary phases (CSPs) were undertaken. These investigations were carried out in an effort to understand the recognition processes responsible for the observed enantioselectivities on the CSPs of interest. Several spectroscopic and chromatographic approaches were taken to establish working models for the recognition processes involved. Specifically, the spectroscopic ($\sp1$H-NMR) studies focused on the solution state behaviors of several CSP analogs in the presence of the individual enantiomers of suitable analytes. Based on observed chemical shift changes and intra- and intermolecular nuclear Overhauser effects upon complexation, conclusions were made with regard to the validity of the initially proposed chiral recognition mechanisms. The chromatographic studies were derived from a basic understanding of these recognition mechanisms. In one case, the role of CSP rigidity is probed and in another, the importance of selector orientation with respect to the underlying silica support is investigated.
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign