Homo- and heteronuclear 2D NMR approaches to analyse a mixture of deuterated unlike/like stereoisomers using weakly ordering chiral liquid crystals

Karim Ben Ali; Olivier Lafon; Herbert Zimmermann; Eric Guittet; Philippe Lesot

doi:10.1016/j.jmr.2007.04.007

Homo- and heteronuclear 2D NMR approaches to analyse a mixture of deuterated unlike/like stereoisomers using weakly ordering chiral liquid crystals

J Magn Reson. 2007 Aug;187(2):205-15. doi: 10.1016/j.jmr.2007.04.007. Epub 2007 Apr 20.

Authors

Karim Ben Ali¹, Olivier Lafon, Herbert Zimmermann, Eric Guittet, Philippe Lesot

Affiliation

¹ Laboratoire de Chimie et Biologie Structurales, ICSN/Centre National de la Recherche Scientifique UPR 2301, Gif-sur-Yvette 91198, France.

PMID: 17513148
DOI: 10.1016/j.jmr.2007.04.007

Abstract

We describe several homo- and heteronuclear 2D NMR strategies dedicated to the analysis of anisotropic (2)H spectra of a mixture of dideuterated unlike/like stereoisomers with two remote stereogenic centers, using weakly orienting chiral liquid crystals. To this end, we propose various 2D correlation experiments, denoted "D(H)(n)D" or "D(H)(n)C" (with n=1, 2), that involve two heteronuclear polarization transfers of INEPT-type with one or two proton relays. The analytical expressions of correlation signals for four pulse sequences reported here were calculated using the product-operators formalism for spin I=1 and S=1/2. The features and advantages of each scheme are presented and discussed. The efficiency of these 2D sequences is illustrated using various deuterated model molecules, dissolved in organic solutions of polypeptides made of poly-gamma-benzyl-L-glutamate (PBLG) or poly-epsilon-carbobenzyloxy-L-lysine (PCBLL) and NMR numerical simulations.