Asymmetric phthalocyanines conjugated on silica for the photocatalytic degradation of organic pollutants synthesis,characterization and investigation of the photophysicochemical properties

Abstract

A series of novel asymmetric metallo (Mg, Zn and Ga) phthalocyanines were synthesized using different ratios of starting materials. After purification, these compounds were obtained in high yields. The asymmetric phthalocyanines were characterized by ultraviolet-visible (UV–vis), infrared (IR) and ¹H NMR spectroscopy, mass spectrometry (MS) and elemental analysis. High solubility in organic solvents was observed because of the ester moiety at the peripheral position, and no aggregation was observed over a wide concentration range. The photophysicochemical properties of magnesium (3a), zinc (3b) and gallium (3c) phthalocyanines were examined. The highest singlet oxygen quantum yield of 0.66 was obtained for 3c. The photophysicochemical measurements demonstrate clearly the potential of these asymmetrical phthalocyanines as photocatalytic agents in the photodegradation of organic pollutants in wastewaters. The zinc complex (3b) was attached onto silica as a solid support, and photocatalytic degradation studies were carried out using Orange G to provide a typical organic pollutant.