Synthesis, characterization and dielectric properties of novel phthalocyanines bearing an octa-peripherally substituted mercaptoquinoline moiety

The synthesis, characterization, spectral and dielectric properties of peripherally (α) octa-mercaptoquinoline substituted Zn(II), Lu(III), Fe(III) and In(III) phthalocyanines are described for the first time. These complexes (2–5) and their precursor are characterized by elemental analysis, FT-IR, 1H NMR, electronic spectroscopy as well as mass spectroscopy. Complexes 2–5 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in any of the solvents over a wide concentration range. The dielectric properties and the dc conduction properties of 2–5 were investigated as a function of frequency and temperature. The dielectric properties were studied in the frequency range 400–1 × 106 Hz. and in the temperature range 300–500 K. It has been observed that both the dielectric constant (ε′(ω)) and dielectric loss (ε″(ω)) decrease with the rise in frequency, but increase with the rise in temperature. From the analysis of the dc conductivity (σdc) dependence on temperature, a weak temperature dependence in the low temperature region and a strong temperature dependence in the higher temperature region was observed for films of 2–5, which indicates the involvement of two conduction mechanisms.

Graphical abstractThe synthesis, characterization, spectral and dielectric properties of peripherally (α) octa-mercaptoquinoline substituted Zn(II), Lu(III), Fe(III) and In(III) phthalocyanines are described. The dielectric properties and the dc conduction properties of these compounds were investigated as a function of frequency and temperature. Both the dielectric constant (ε′(ω)) and dielectric loss (ε″(ω)) decrease with a rise in frequency and they increase with a rise in temperature From the analysis of the dc conductivity (σdc) dependence on temperature, a weak temperature dependence in the low temperature region and a strong temperature dependence in the higher temperature region was observed for films of the Zn(II), Lu(III), Fe(III) and In(III) phthalocyanines.Figure optionsDownload full-size imageDownload as PowerPoint slide