Pyridine Directed Assembly of Tetra-O-Alkyl p-Carboxylatocalix[4]arenes

A crystallization study of four tetra-O-alkyl p-carboxylatocalix­[4]­arenes from a series of pyridine derivatives has been carried out to investigate the effects of varying the length of the calixarene lower-rim alkyl group introduced, and the introduction of alkyl groups around the pyridine guest/template. Analysis of 11 of 24 possible sets of single crystals formed shows trends in self-assembly based on the availability of the calixarene cavity for guest/template inclusion, either Py···CO2H or CO2H···CO2H synthons, and dominance of one synthon over the other depending on the position of alkyl groups around the pyridine ring.