Syntheses, Crystal Structures and Complexing Properties of 1,3-Distal Calix[4]arene Schiff Bases

Novel 1,3-distal p-tert-butylcalix[4]arene Schiff bases were efficiently synthesized in three steps.At first p-tert-butylcalix[4]arene was reacted with N-2-hydroxyethylphthalimide catalyzed by TPP/DEAD or alkylated with w-haloalkylphthalimide in the system of K_2CO_3/KI/CH_3COCH_3 to give 1,3-distal diphthalimidoalkyl calixarenes,which were in turn hydrazinolyzed to give diaminoalkyl calixarenes.Then with the aid of the condensation of active calixarene amines with salicylaldehyde,2-hydroxy-1-naphthaldehyde or pyridine-2-carboxaldehyde,a series of 1,3-distal calixarene Schiff bases was prepared in satisfied yields.The single crystal structures and complexing properties of these Schiff bases for transition metal ions were studied.