Magnetic and electrical properties of poly(3-radical-substituted thiophene)s

Radical groups, tert-butylnitroxide, nitronyl nitroxide, and 2,6-di-tert-butylphenoxyl, were introduced at the 3-position of thiophene, and the thiophene derivatives were then polymerized to yield poly(3-radical-substituted thiophene)s. The acetoxyphenyl-substituted thiophene gave regio regular poly(3-phenol-subslituted thiophene) via oxidative polymerization with ferric chloride at low temperature, while the polymerization of the amine-substituted thiophenes did not proceed with any oxidizing agents under any reaction conditions. The phenoxyl-substituted polyradicals, 7 and 8, with spin concentrations of 0.30 and 0.25, respectively, displayed S values of 2/2 to 3/2 and 2/2, respectively, indicating an intramolecular ferromagnetic spin-coupling through the polythiophene backbone. The polyradicals, 7 and 8, themselves and the polyradical doped with iodine showed an electrical conductivity of 10(-5) and 10(-2 similar to) (-1) S cm(-1), respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.