The NMR Spectra of Samples Dissolved in Liquid–Crystalline Phases: Automatic Analysis with the Aid of Multiple Quantum Spectra— The Case of Flexible Molecules

Abstract

Homonuclear NS = 0 and heteronuclear NS ≠ 0 multiple quantum spectra, involving changes in the magnetic number mI by (NI−1), (NI − 2), and (NI−3), with NI and NS the number of interacting nuclei of magnetogyric ratio γI and γS, are used for the automatic analysis of 1H NMR spectra of flexible molecules dissolved in liquid–crystalline phases. The automatic procedure has been applied to study molecules of general formula Ph–CH2–X starting from a parameter set having all the spectral parameters set to zero. The results of such an analysis are then used as starting parameters for analysis of the single quantum spectrum. The method was first tested when X = Br and X = H in order to compare strategies differing for the types of parameters used and was then applied to the analysis of 3-phenylprop-1-yne.