Investigation of the enantioselectivity of three polypeptide liquid-crystalline solvents using NMR spectroscopy.
The enantioselective potentialities of three polypeptide liquid-crystalline solutions made of poly-gamma-benzyl-L-glutamate (PBLG), poly-gamma-ethyl-L-glutamate (PELG) or poly-epsilon-carbobenzyloxy-L-lysine (PCBLL) are investigated and compared using proton, carbon-13 and deuterium NMR spectroscopy. From a practical point of view, we propose an efficient alternative to the PBLG system, which is essential when this chiral homopolymer fails in distinguishing between enantiomers or enantiotopic elements. From a theoretical point of view, this study provides new information on the role of the lateral side chain of the polypeptide in the mechanisms of enantiodiscrimination. The various experimental results reported show the extraordinary adaptability of this methodology, and so enlighten the very large potential of NMR in chiral liquid crystals in the field of enantiomeric and enantiotopic analysis.
Aroulanda
C
C
Laboratoire de Chimie Structurale Organique, CNRS ESA 8074, ICMO, Université de Paris-Sud, Orsay, France.
Sarfati
M
M
Courtieu
J
J
Lesot
P
P