ESR Studies on C60.OXand C60.HMTTEF

Autor: J. V. Acrivos, D. E. Morris, L. Chen, Thalappil Pradeep, K. K. Singh
Rok vydání: 1996
Předmět:
Zdroj: Fullerene Science and Technology. 4:583-598
ISSN: 1064-122X
DOI: 10.1080/10641229608001572
Popis: The electron spin resonance (esr) of C60.Ox and C60.HMTTEF (hexamethylentetratellurafulvalene) has been investigated at 9.36 GHz as a function of temperature. T (298 T 4 K). C60.Ox shows an esr absorption of equal ‘g’ value to that of C60 exposed to O2 and light but is more intense. The C60 in its pure form is in a singlet state. The impurity sites introduced by O2 produce the esr absorption. The Curie - Weiss plots of inverse esr absorption intensity versus temperature indicate an antiferromagnetic TH = 50 for air exposed C60 and 90K for C60Ox. From the esr intensity at room temperature, the calculated number of free spins (S = 1/2) is =1/3 per mole of C60-Ox. In case of C60.HMTTEF, there is a very weak esr absorption at room temperature suggesting that the room temperature form is diamagnetic with very small charge transfer between C60 and HMTTEF. This conclusion is consistent with the structure and magnetic susceptibility of this cocrystal. As the temperature is lowered, the equilibrium: AD
Databáze: OpenAIRE