Synthesis, thermal, and electrical properties of stilbene-bridged polymeric zinc phthalocyanine

Diethylstilbesterol diphthalonitrile ether (1) was synthesized by nucleophilic aromatic substitution of diethylstilbesterol onto 4-nitrophthalonitrile. A polymeric zinc phthalocyanine (2) was prepared by polymeric tetramerization of the tetranitrile monomer with Zn(CH ₃)₂·2H₂O. Thermal analysis of the polymeric zinc phthalocyanine was performed by differential scanning calorimetry and thermal gravimetric analysis. Dc and ac conduction properties of polymeric zinc phthalocyanine pellet were investigated in the frequency range of 100 to 1.6 × 10⁶ Hz and temperature 300-505 K. σ_dc was found to follow a variable range hopping mechanisms up to ~400 K. Above this temperature, σ_dc followed thermally activated conduction mechanism only. Based on the existing theories of ac conduction, it was concluded that the temperature dependence of the exponent 's' and conductivity, the correlated barrier hopping model is the dominant conduction mechanism for electron transport in the polymeric zinc phthalocyanine pellet.