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

A crystallization study of four tetra-O-alkyl pcarboxylatocalix[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 center dot center dot center dot CO2H or CO2H center dot center dot center dot CO2H synthons, and dominance of one synthon over the other depending on the position of alkyl groups around the pyridine ring.