Synthesis and structure of nitrogen bridged calix[5]- and -[10]-pyridines and their complexation with fullerenes

Abstract

Azacalix[5]pyridine, a heteroatom bridged calixaromatic with an odd number of arene units, and azacalix[10]pyridine, a giant molecular belt, were selectively synthesized based on a 2 + 3 macrocyclic coupling strategy; both novel macrocyclic hosts formed strong 1 : 1 complexes with fullerenes C₆₀ and C₇₀ in a size-selective manner with association constants up to 1.3 × 10⁵ ± 0.03 × 10⁵ M^–1.