Synthesis, Structures, and Assembly of Geodesic Phenine Frameworks with Isoreticular Networks of [n]Cyclo-para-phenylenes

A series of macrocycles were designed by rendering geodesic phenine frameworks in isoreticular networks of [n]cyclo-para-phenylenes. Large, nanometer-sized molecules exceeding molecular weights of 2000 Da were synthesized by five-step transformations including macrocyclization of [6]cyclo-meta-phenylene panels. The dependence of both the molecular structures and the fundamental properties on the panel numbers was delineated by a combination of spectroscopic and crystallographic analyses with the aid of theoretical calculations. Interestingly, flexibility of the molecules via panel rotations depends on the hoop size, which has not been disclosed with the small isoreticular [n]cylco-para-phenylenes. One of the macrocycles served as a host for C-70, and its association behaviors and crystal structures were revealed.