Characterization of the F-19 chemical shielding tensor using cross-correlated spin relaxation measurements and quantum chemical calculations

摘要

The F-19 chemical shift anisotropy (CSA) tensor is an indispensable structure estimation tool in the NMR investigations of flourinated biomolecules. This work focuses on the characterization of the F-19 CSA tensor in small molecules, through the combined use of quantum chemical methods and liquid-state NMR cross-correlated spin relaxation experiments. The effect of different basis sets and quantum computational methods on the magnitude and orientation of the F-19 CSA tensor are discussed. The results from ab initio methods and the liquid-state relaxation experiments match well and are comparable to values of the CSA tensor obtained from previous solid-state studies and from theoretical investigations of similar molecules. (C) 2010 Elsevier B.V. All rights reserved.