Novel calixarene–Schiff bases that bind silver(I) ion

Two novel calix[4]arene–Schiff base receptors have been synthesized. One of the new compounds has two pendant aldimines, while the second has been prepared by two-point attachment of a calixarene–dialdehyde onto a calixarene–diamine to form a “calix-tube”. Preliminary binding studies with AgClO4 show large complexation-induced shifts in 1H NMR positions.