π-Conjugated Polyradicals Containing Anthracene Skeleton in the Backbone Chain

Abstract

The bromoethynylanthracene monomer with 3,5-di-tert-butyl-4-acetoxyphenyl group was newly synthesized and was polymerized by Pd(0) catalyst to give the head-to-tail regulated polymer with DP = 12. The ESR spectra of the anthracene-based polyradical suggested an effectively delocalized spin distribution on the backbone anthracene. The δm_s = ±2 forbidden transition ascribed to the triplet species was observed at g = 4 in frozen toluene glass. Magnetization and static magnetic susceptibility of the polyradical were measured using a SQUID magnetometer. The average spin quantum number was beyond S = 1/2, indicating the ferromagnetic interaction.

Key Words:

• polyradical
• poly(anthraceneethynylene)
• ladder polymer
• phenoxy radical
• magnetic ineteraction
• molecule-based magnets