1991 Volume 64 Issue 6 Pages 1896-1900
Calix[n]arenes (n=4 and 6) bearing (S)-5-oxo-2-pyrrolidinylcarbonyloxyl groups on the lower rim were synthesized. In chloroform, the hexamer bearing six (S)-5-oxo-2-pyrrolidinylcarbonyloxyl groups could “bind” ferrocenecarboxylic acid through hydrogen-bonding interactions, the complexation being conveniently detected by induced circular dichroism (ICD) spectroscopy (λmax 445 nm). On the basis of the examination of acyclic reference compounds, the appearance of the ICD band was explained as such that one pyrrolidone unit acts as a binding site and the chiral center in the neighboring pyrrolidone unit affects the transition moments in the ferrocene π-system. The association constant for the 1 : 1 complex was estimated to be 680 M−1. This is a new, convenient method for detecting the formation of molecular complexes with calixarenes in organic media.
This article cannot obtain the latest cited-by information.