Magnetic properties of verdazyl free radicals. VII. π-Bridged verdazyl biradicals with triplet ground state
- 15 September 1974
- journal article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 61 (6) , 2294-2296
- https://doi.org/10.1063/1.1682306
Abstract
Magnetic susceptibilities of two π‐bridged verdazyl biradical solids have been measured in the temperature range 1.8−300°K. Paramagnetic Curie constants of 1.0±0.1 and 0.90±0.05 K·emu/mol have been found in 1,4‐bis(1,5‐diphenyl‐3‐verdazyl)benzene (P‐verdazyl) and 1,3‐bis(1,5‐diphenyl‐3‐verdazyl)benzene (M‐verdazyl), respectively. Both Curie constants suggest the presence of the triplet ground state. The intramolecular positive exchange integrals, J/k, of these biradicals are much greater than 300°K. The susceptibility of P‐verdazyl exhibits a maximum at 19±1°K, which implies a negative exchange interaction between the triplets, its magnitude being estimated to be about 7°K.Keywords
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