Novel metal (II) phthalocyanines with 3,4,5-trimethoxybenzyloxy-substituents: Synthesis, characterization, aggregation behaviour and antioxidant activity

Abstract

A new substituted phthalonitrile derivative was prepared by a nucleophilic displacement reaction of 3,4,5-trimethoxybenzyl alcohol with 4-nitrophthalonitrile. Novel metallophthalocyanines IM: Zn (II), Co (II), Ni (II)1 with four peripheral 3,4,5-trimethoxybenzyloxy groups were synthesized by cyclotetramerization of phthalonitrile derivative. These compounds were purified by crystallization and column chromatography. They were characterized by elemental analysis, FTIR, H-1 NMR, C-13 NMR and UV-VIS spectral data. The aggregation investigations carried out in different concentrations indicate that 3,4,5-trimethoxybenzyloxy-substituted phthalocyanine compounds do not have any aggregation behaviour in concentration range of 10(-2)-10(-8) M. The antioxidant activities of phthalocyanines were investigated by in vitro antioxidant assays such as free radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferrous ion chelating ability. The highest DPPH activity and ferrous ion chelating activity were obtained from Tetrakis [(3,4,5-trimethoxybenzyloxy) phthalocyaninato] cobalt and 4-(3,4,5-trimethoxybenzyloxy) phthalonitrile, respectively. 4-(3,4,5-trimethoxybenzyloxy) phthalonitrile was shown to have a fairly ferrous ion chelating activity. (C) 2012 Elsevier Ltd. All rights reserved.