Makoto Miyasaka

Average Octet Radical Polymer: A Stable Polyphenoxyl with Star-Shaped π Conjugation

An average spin quantum number of 7/2 is displayed by the star-shaped, π-conjugated polyradical 1, even with a spin concentration of 0.8 per monomer unit. Polymer 1 is stable at room temperature, and it is a powerful candidate for the synthesis of a feasible polymer with very high spin.

Hyperbranched poly(phenylenevinylene) bearing pendant phenoxys for a high-spin alignment

2,6-Dibromo-4-(3′,5′-di-tert-butyl-4′-acetoxyphenyl)styrene was polymerized in a one-pot reaction using a palladium catalyst, and subsequent hydrolysis and oxidation yielded the hyperbranched poly[(4-(3′,5′-di-tert-butyl-4′-ylooxyphenyl)-1,2,(6)-phenylenevinylene)], which three-directionally satisfies both an alternant but non-Kekule-type π-conjugation and the ferromagnetic connectivity of the unpaired electrons of the pendant phenoxyl. The AFM image, unusually low solution viscosity, and low chemical reactivity of the phenol group indicated the polymer to have a highly branched and globular structure. In spite of the extremely crowded branching, π-conjugation in the polymer skeleton was maintained, as indicated by photoelectron and EPR spectroscopies. The phenoxyl polymer even with a spin concentration of only 0.4 spin per monomer unit displayed an average S value of 3.

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

Abstract 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 regioregular poly(3-phenol-substituted 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∼−1 S cm −1 , respectively.

Ein stabiles Polyphenoxyl mit sternförmiger π‐Konjugation: Oktett‐Zustand im Mittel

Eine Spinquantenzahl von 7/2 weist das sternformige, π-konjugierte Polyradikal 1 selbst bei einer Spinkonzentration von 0.8 pro Monomereinheit auf. 1 ist bei Raumtemperatur stabil und ist vielversprechend fur die Synthese eines praktikablen Polymers mit sehr hohem Spin.