New Metallophthalocyanines Posture Pyridine Pendants Via 1,3,4-Oxadiazole Bridge: Synthesis, Optical and Electrical Studies
The new symmetrically tetra substituted metallophthalocyanines (MPc) [MPc1-3, M = Co(II), Ni(II) and Cu(II)] bearing pyridyl moieties on peripheral positions have been synthesized via 1,3,4-oxadiazole bridge. The newly prepared compounds have been characterized by elemental analysis, FTIR, Solid State 13C NMR, Solid State UV–Vis, Thermogravimetric Analysis (TGA) and XRD analysis, the complexes are in good consistency with the experimental results. All the newly synthesized compounds exhibited good optical property showing the red shift of Q-band position and TGA results show admirable thermal stability (>400 °C). The MPc2 and 3 show high dielectric constant (ÃÂ′), 9800 and 11150 respectively, at 50 Hz. The ensuing MPc1-3 show low dielectric loss (tanδ) in the frequency range of 50 Hz to 5 MHz at room temperature. The shoulder nature is observed in the variation of tanδ with frequency for MPc2 and MPc3, which is understood on the basis of resonance between hopping frequencies of charge carriers and applied frequency. The variation of AC conductivity with frequency was explained by electron hopping model and values are in the range of 4.0x10-5–1.6x10-4 (S/m) at 5 MHz measured at 20 °C.