Water-soluble axially disubstituted non-aggregated silicon phthalocyanines and their electrochemical properties

A series of two novel silicon phthalocyanines 3, 5 and their water-soluble derivatives 3a, 5a have been synthesized by introducing 2-{2-[3-(dimethylamino)phenoxy]ethoxy}ethanol and 2-{2-[3-(diethylamino)phenoxy]ethoxy}ethanol at the axial positions of silicon(IV) phthalocyanine, respectively. The aggregation behaviour of these compounds was investigated in different solvents and concentrations of DMSO and water. Silicon phthalocyanine complexes 3 and 5 and their water-soluble derivatives 3a and 5a did not show any aggregation in CHCl3, CHCl3, DMF, DMSO, THF, EtOH, EtOAc and water. The electrochemistry of complexes 3, 5 was also studied by cyclic voltammetry (CV) and square wave voltammetry (SWV) methods. Complexes 3 and 5 exhibit two reversible Pc ring-based one-electron reduction couples and two quasi-reversible Pc ring-based one-electron oxidation couples. (C) 2013 Elsevier Ltd. All rights reserved.