Research into methanofullerenes with various substitution degrees by UV spectroscopy

Abstract

A qualitative and quantitative UV spectroscopic study of C₆₀ fullerene and methanofullerene (1,2-dihydro-C₆₀-fullerene) compounds differing in the degree of functionalization has been carried out. In solvents with different polarities, the molar absorptivity of C₆₀ and the mono-substituted 1,2-dihydro-C₆₀-fullerenes has been determined. It was found that the extinction coefficient of C₆₀ at 330 nm does not depend on the solvent nature and amounts to ∼54 400 M⁻¹ cm⁻¹. The molar absorption coefficients of the mono-substituted 1,2-dihydro-C₆₀-fullerenes are practically independent of the chemical structure and length of the substituent. As for the methanofullerene compounds with different degrees of functionalization, it is shown that as the number of substituents increases, a hypsochromic shift of the characteristic absorption bands and a decrease in the optical density of these substances in solution occur. An exponential dependence of molar absorption methanofullerene coefficients from the degree of fullerene compounds is revealed. A spectroscopic method for analyzing the methanofullerene compounds with different numbers of substituents has been developed. The good reproducibility and sensitivity of the methods suggested are demonstrated on model mixtures of fullerene derivatives. An analysis of the reaction mixture obtained by the interaction of fullerene and diallyl ether malonate is also given.