Homoheteracalix[n]arenes (X = S, Se, N)

Abstract

The expanded analogs of the calix[n]arenes in which the aryl units are (meta) connected via a polyatomic rather than a CH2 or heteroatom bridge can be called homocalix[n]arenes, and more particularly homoheteracalix[n]arenes if at least one heteroatom is part of the bridge. The first examples of systems with sulfur heteroatoms were reported in the 1970s. Recently, there has been an increasing interest in these macrocyclic systems and also the selenium analogues were prepared. In this chapter, we report on the different approaches to homothiacalix[n]arenes, homoselenacalix[n]arenes and homoazacalix[n]arenes, and their structural characteristics. The synthetic methods available to obtain the macrocycles from simple starting materials have opened up opportunities for applications for these novel compounds.