Directory
Chiral cryptophanes and their properties
Over the past few years, we have developed a novel approach to prepare enantiopure cryptophanes and to study their chiroptical properties by Electronic Circular Dichroism (ECD) and Vibrational Circular Dichroism (VCD). This approach, based on the separation by crystallization of cryptophane diastereomers, provides the two enantiomers of cryptophanol-A derivatives in fair amount (ee > 98 %). Cryptophanols-A were used to synthesize new enantiopure derivatives that cannot be easily obtained by the conventional approaches. In addition, the access to enantiopure materials allows the study of the chiroptical properties of cryptophane derivatives by modern spectroscopic techniques. Thus, we have demonstrated that VCD spectroscopy combined to DFT calculations (B3PW91/6-31G*) allows the determination of the absolute configuration (AC) of cryptophane derivatives (J. Am; Chem. Soc. 2006; J. Org. Chem. 2008; J. phys. Chem. A 2008). Besides the direct AC determination of cryptophanes. These studies have revealed that the conformation of the linkers is strongly dependent on the presence and the size of a guest molecule inside the cryptophane cavity.
