S. Blanchard et al., A novel calix[6]arene-based mononuclear copper(I) complex that exhibits chirality at low temperature, NEW J CHEM, 22(11), 1998, pp. 1143-1146
A calix[6]arene functionalized in alternate positions at the lower rim with
three picolyl groups acts as a biomimetic N3 ligand with cuprous ion. The
stable C-3 symmetrical complex derived from CuCl exists as a pair of helica
l enantiomers. A low temperature H-1 NMR study revealed that the chirality
is transmitted to the calixarene skeleton, thereby providing a chiral cavit
y around the apical binding site of the metal center.