Synthesis and properties of new calix[4]arene containing diacetylene pendants

Abstract

Topological polymerization required specific supramolecular assembly of the monomer molecules that can provide unique structures of polymer can not be attained by conventional polymerization. The best known topological polymerization to date involves diacetylene monomers to produce the corresponding ene-yne conjugated polydiacetylenes. The new series of tert-butylcalix[4]arene derivatives containing 2-4 diyne chains on the phenoxy rim were synthesized in this dissertation in the attempt to demonstrate the first polymerization through a topological intramolecular 1,4-addition of diyne. The copper-catalyzed coupling reaction of multipropynyl-tert-butylcalix[4]arene with 5-iodo-4-pentynol in pyrrolidine constitutes the key step in the synthesis of the diynes chain. The solid-state photopolymerization study indicates that only the calix[4]arene derivatives containing four diyne units with alkyl urethane groups can be topologically polymerized to afford polydiacetylenes containing calix[4]arene. The length of alkyl linker between the diyne and carbamate group also has a pronounced effect on the polymerizability of the diyne units. The visible absorption band at 350-600 nm and the Raman signals around 1500 and 2100 cm-1 signified the ene-yne conjugation of the resulting polymers. The polydiacetylenes obtained displayed the formation of nanodisk in water and tetrahydrofuran probably through a micelle type self-assembly. The polymers also exhibited reversible red to yellow thermochromism near 120 ºC.