Thermochemical and microstructural studies on binary organic eutectics and complexes

The phase diagram, solidification kinetics and differential scanning calorimetry of a few charge-transfer (CT) complexes of pyrene with p-benzoquinone, m-dinitro benzene and m-nitrobenzoic acid have been studied. These materials have been characterized by X-ray diffraction. Microstructure and electrical conductivities of congruent melting complexes and eutectics have been determined. The data indicate that side-by-side nucleation of donor and acceptor results both in eutectic as well as CT complex formation under the present experimental conditions. This explains low electrical conductivities of these materials due to weak interaction and mixed stacking of donor and acceptor. Excess thermodynamics functions of the CT materials and eutectics have been determined and results have been discussed in the light of electron donor-acceptor interactions between the components. (C) 2004 Elsevier B.V. All rights reserved.