Vibrational circular dichroism study of optically pure cryptophane-A

Thierry Brotin; Dominique Cavagnat; Jean-Pierre Dutasta; Thierry Buffeteau

doi:10.1021/ja0603148

Vibrational circular dichroism study of optically pure cryptophane-A

J Am Chem Soc. 2006 Apr 26;128(16):5533-40. doi: 10.1021/ja0603148.

Authors

Thierry Brotin¹, Dominique Cavagnat, Jean-Pierre Dutasta, Thierry Buffeteau

Affiliation

¹ Laboratoire de Chimie de l'ENS-LYON (UMR 5182-CNRS), Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon 07, France.

PMID: 16620127
DOI: 10.1021/ja0603148

Abstract

Vibrational circular dichroism (VCD) measurements and density functional theory (DFT) calculations were used to obtain the absolute configuration of optically pure cryptophane-A molecule. This large molecule (120 atoms) that possess a globular shape, but no chiral centers, exceeds the molecular size of published structures for which VCD has been used to determine the absolute configuration. VCD spectra recorded in CDCl(3) solution for the two resolved enantiomers are near mirror images, and very good agreement between the observed IR and VCD spectra and intensity calculations performed at the DFT (B3PW91/6-31G) level establish, besides the absolute configuration, the preferential anti conformation of the aliphatic linkers of the chloroform-cryptophane-A complex. Experiments performed in CD(2)Cl(2) and C(2)D(2)Cl(4) solutions show no significant modifications in the IR and VCD spectra, indicating that the conformation of the aliphatic linkers is similar for empty (C(2)D(2)Cl(4) solution) and encaged (CDCl(3) and CD(2)Cl(2) solutions) cryptophane-A molecules.