Absorption spectroscopic study of EDA complexes of [70]fullerene with a series of methyl benzenes

[70]Fullerene has been shown to form 1:1 molecular complexes with toluene, p-xylene, m-xylene, 1,2,4,5-tetramethyl benzene (durene) and pentamethyl be nzene (PMB) in CCl4 medium by absorption spectroscopic method. Isosbestic p oints have been detected in case of complexes with PMB and durene. Charge t ransfer absorption band could not be detected but the intensity of the broa d absorption band of C-70 in CCl4 decreases systematically with increase in the concentration of the added methylbenzenes. From this trend the formati on constants (K-c) of the complexes have been determined at three different wavelengths. The constancy of K-c with respect to change in the wavelength of measurement supports the view that complex of a single stoichiometry (1 :1) is formed in each case. (C) 2001 Elsevier Science B.V. All rights reser ved.