Relation between the Chemical Composition and the Electronic Properties of the Charge-Transfer Complex, p-Chloranil: p-Phenylenediamine

Abstract

The charge‐transfer complex p‐chloranil:p‐phenylenediamine has been prepared by three methods: (a) precipitation from benzene, (b) precipitation from methylene chloride, (c) direct reaction between the dry solid constituents. A 1:1 complex was found in all cases, with entrapped solvent present in the cases of samples precipitated from solution. It has been shown that the concentration of unpaired electron spins and the conductivity are characteristic of the complex and do not depend upon the method of preparation. The thermal activation energy for conductivity has been found to be 0.43 eV, and for spin concentration it has been found to be 0.13 eV. Theoretical difficulties involved in the consideration of activation energies are discussed. A mechanism is considered in the light of the thermal activation energies and the Seebeck coefficient, which was found to be +1.4 mV/°C.