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

Radical groups, tert-butylnitroxide, nitronyl nitroxide, and 2,6-di-tert-bu tylphenoxyl, were introduced at the 3-position of thiophene, and the thioph ene derivatives were then polymerized to yield poly(3-radical-substituted t hiophene)s. The acetoxyphenyl-substituted thiophene gave regio regular poly (3-phenol-subslituted thiophene) via oxidative polymerization with ferric c hloride at low temperature, while the polymerization of the amine-substitut ed thiophenes did not proceed with any oxidizing agents under any reaction conditions. The phenoxyl-substituted polyradicals, 7 and 8, with spin conce ntrations 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-coup ling through the polythiophene backbone. The polyradicals, 7 and 8, themsel ves 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 Else vier Science Ltd. All rights reserved.