DSC studies of aromatic hydrocarbon picrates

Melting temperatures, enthalpies and entropies of fusion of a number of crystalline, charge-transfer complexes of aromatic hydrocarbons with 2,4,6-trinitrophenol (picric acid) have been measured, together with the corresponding data for some aromatic hydrocarbons themselves and for picric acid. The data suggest that for this, and for other nitro-aromatic acceptor molecules, enthalpies of fusion of charge-transfer complexes reflect the complexing ability of the electron acceptor, although the contribution of the charge-transfer interaction to the measured enthalpy is small.