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

A number of tetraazacalix[ 2] arene[ 2] triazines bearing different substituents on the bridging nitrogen atoms were synthesized efficiently using a fragment coupling strategy. The N- arylation of the parent azacalix[ 2] arene[ 2] triazine afforded tetra( arylaza) calix[ 2] arene[ 2] 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.