N‐Substituted Azacalixphyrins: Synthesis,Properties, and Self‐Assembly

Pre‐ and postintroduction of substituents with respect to the macrocyclization step leads to previously unknown N‐substituted azacalixphyrins. The stepwise synthetic approach has been studied in detail to highlight the key role of the N‐substituents of the precursors and/or intermediates in terms of reactivity. Based on a combined experimental and theoretical investigation, the relationship between the properties of the macrocycles and their degree of substitution is rationalized. Depending on the nature of the N‐substituents, the formation of supramolecular ribbon‐like structures could also be observed, as demonstrated by combined TEM, SEM, AFM, and FTIR experiments.