Synthesis of New Chromogenic Calix[4]arenes Bridged at the Upper Rim through Bisazobiphenyl Linkages

Synthesis of new chromogenic calix[4]arenes through the coupling of diazotized 4,4‘-diaminobiphenyls and calix[4]arenes at the upper rim is described. Analysis of the synthesized bisazobiphenyl-bridged calixarenes by NMR and CPK models suggest that the bisazobiphenyl linkage is on the transannular phenyl groups of the calixarene moiety in the 1,3-alternate conformation.