Developments in nmr in liquid crystalline solvents

Abstract

This paper describes some recent developments in the technique of molecular structure determination from nmr in liquid crystalline solvents. 1. An INDOR double resonance method, which can be helpful in the analysis of complex spectra, is described and applied to the spectrum of bicyclobutane. 2. In more complex molecules, extensive overlap of peaks can make interpretation impossible. It is shown that deuterium substitution will greatly simplify the spectra. Decoupling of the deuterium is achieved by irradiation of a double quantum transition. Spectra for cyclohexane are presented. 3. A very simple model for estimating corrections for molecular vibrations is presented. In this model, only the vibrations of the hydrogen atoms, relative to a rigid framework of the heavier atoms, are taken into account. 4. Ditchfield and Snyder have made ab initio molecular orbital calculations for the anisotropy of the indirect couplings. Their principal results for methyl fluoride are presented. it is concluded that in many cases corrections for these couplings are negligible.