Synthesis and Crystal Structure of a Calix[4]arene-Based Dual Boron–Dipyrrin System.

The preparation of a calix[4]arene-based dual boron–dipyrrin system was accomplished by the condensation of diformylcalix[4]arene and pyrrole followed by a treatment with DDQ and diethyl ether–boron trifluoride (1/1). An X-ray crystal structure analysis and spectroscopic measurements revealed that the cone conformation of calix[4]arene serves to define 14.9 Å as the center-to-center boron–dipyrrin separation.