Synthesis of tetraazacalix[2]arene[2]triazines: tuning the cavity by the substituents on the bridging nitrogen atoms

Structure: see text] A number of tetraazacalix2]arene2]triazines bearing different substituents on the bridging nitrogen atoms were synthesized efficiently using a fragment coupling strategy. The N-arylation of the parent azacalix2]arene]2]triazine afforded tetra(arylaza)calix2]arene2]triazine in 91% yield. The introduction of different substituents on the bridging positions led to the regulation of the cavity of the resulting macrocyclic molecules.