NMR studies of flexible molecules in the nematic mesophase

Horne, Timothy James (1990) NMR studies of flexible molecules in the nematic mesophase. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

NMR spectroscopy has been used widely in the study of molecules in liquid crystalline mesophases. In the work described in this thesis, proton, deuteron and fluorine NMR is used to study the conformations and orientational order of both nematogens and solutes dissolved in nematic solvents. The first two experimental chapters, chapters 2 and 3, describe investigations of the nematogen 4-methoxy-4'-cyanobiphenyl (1-OCB); the first of these is a study of the structure and ordering of 1-OCB molecules in its mesophase, and the second, which is an investigation of the possible existence of pairs of interacting molecules in 1-OCB, describes the study of nematic solutions of which 1-OCB is a part. Chapter 4 is concerned with the same theme as chapter 3, and is an investigation of the orientational ordering of solutes in 1-OCB. The second member of the n-OCB homologous series, 2-OCB, is investigated in chapter 5, and models for the conformations adopted by the ethoxy chain examined. In the final chapter, chapter 6, the utility of the nematic mesophase as a solvent in which the conformations adopted by non-rigid solutes can be determined is demonstrated; two α,α,α-trifluoro- derivatives of methoxybenzene (anisole) are studied, and it is shown that the preferred conformations of these molecules are quite different from those of the parent molecule, anisole.

This record has no associated files available for download.