Crown ether-substituted water soluble phthalocyanines and their aggregation, electrochemical studies

The synthesis of a new metal-free, zinc (II), cobalt phthalocyanines and their water soluble quaternized derivatives 5a, 6a substituted with four crown ether groups are described. The aggregation behavior of these compounds was investigated in different concentrations of DMSO. The effect of solvents on absorption spectra was studied in various organic solvents. Water soluble phthalocyanines 5a and 6a were investigated for their aggregation behavior in DMSO, DMF, water and in various DMSO/water mixtures by comparing their UV–Vis spectra. Water soluble phthalocyanines in DMSO and in up to 50 vol.% DMSO/water are nonaggregated. But increasing amounts of water leads to higher aggregation ratios. Electrochemical properties of phthalocyanines were investigated by cyclic and square wave voltammetry. While cobalt phthalocyanine displayed metal and ring-based redox processes, the other phthalocyanines displayed only ring-based redox processes.