Absorbance spectrometric study of electron donor acceptor complexes of coal derived asphaltene with [60]- and [70]fullerenes

Coal derived asphaltene (CDA) has been observed to form molecular complexes with electron acceptors such as [60]- and [70]fullerenes in carbon tetrachloride medium. The UV-vis spectroscopic studies show that CDA forms an inclusion complex of 2(CDA):1(fullerene) stoichiometry with [60]fullerene. On the other hand, CDA forms similar complex of 3(CDA):1(fullerene) stoichiometry with [70]fullerene. This is established by determining the thermodynamic parameters such as formation constants, enthalpies and entropies of the complex formation. The results also indicate that the process of complex formation in both the cases is entropy driven one.