Synthesis, Structure and Properties of Core‐Modified Calixporphyrinoids

Calix[n]porphyrinoids containing both sp 2 and sp 3 meso ‐carbons can bind metals like porphyrinoids and anions like calix[n]pyrroles. Thus, calix[n]porphyrinoids are hybrid macrocycles of porphyrinoids and calix[n]pyrroles. The core‐modified calix[n]porphyrinoids resulted by replacing one or more pyrroles of calix[n]porphyrinoids with different heterocycles or carbacycles that possesses very attractive structural, spectral, and coordination properties. For the past two decades, several different types of core‐modified calix[n]porphyrinoids in which one or more pyrroles were replaced with other heterocycles such as thiophene, selenophene, tellurophene, silole, phosphole, pyridine, etc and carbacycles such as m/p ‐phenylene have been synthesized and explored their structure, metal coordination and anion sensing properties. This review describes different synthetic strategies used for the synthesis of various types of core‐modified calix[4]phyrins and expanded calix[n]phyrins and discusses their key structural aspects, properties, coordination chemistry and applications.