Spin dynamics and charge transfer in C60 · 2ferrocene studied by electron spin resonance

Electron spin resonance (ESR) has been applied to study spin dynamics and charge transfer interactions in C60(Fe(C5H5)2)2. A low concentration of C60− spins is derived by ESR, suggesting the presence of weak charge transfer between C60 and ferrocene. The C60− ESR spectra display an appreciable anisotropy at T < 40 K reflecting molecular rotation freezing, while their low temperature variation (T < 10 K) implies development of antiferromagnetic spin–spin interactions. At high temperatures, the narrow ESR line of C120O− impurity spins inhibits observation of a C60− ESR.