Aminu Dauda, Abdul Ademola Olaleye and Hadiza Usman Abdullahi

Keywords: Phthalocyanine, 3-Phthalonitrile, electrochemistry, Thermal analysis

Abstract

In this research, phthalonitrile was synthesized from the reaction of 7-hydroxycoumarin with 3-nitrophthalonitrile in DMF. Cyclotetramerization of phthalonitrile in the presence of metal salt, Fe(II)) gave peripherally substituted metal phthalocyanine complex. The structure of the synthesized compound was characterized by different analytical tools such as 1H NMR, UV-Vis, and FT-IR spectrophotometry and cyclic voltammetry. Disappearance of the C≡N stretching vibration on the IR spectra of phthalonitrile was observed at 2230 cm−1. The FTIR vibration results for C=O, C=C amd C-O were 1712cm-1, 1615 cm-1 and 1276 cm-1 respectively. Solubility of metal phthalocyanine complex was found to be very low in common laboratory solvents such as tetrahydrofuran (THF) and dimethylformamide (DMF). The electronic spectrum of FePc in DMF, shows intense Q absorption at 678 nm. UV-Vis spectra of phthalocyanines showed electronic spectra with two strong absorption bands Q and B bands. The Q band was found in 600–750 nm and B at 300–400 nm. The thermal stability of the phthalocyanine derivative was checked by T.G.A and degradation was observed to start at 380oC which showed that the complex could withstand relatively high temperatures. It was, therefore, concluded that the metal phthalocyanine prepared in this study showed suitably high thermal stability and can be used for various applications