Aggregation equilibria of amphiphilic phthalocyanines substituted by polyethylene oxide in dichloromethane

Abstract

The aggregation equilibria of metal-free and copper(II) phthalocyanine compounds substituted by polyethylene oxide at β (2 or 3, 9 or 10, 16 or 17, 23 or 24) positions, TDEO6-MPc, in deuterated dichloromethane were studied by means of 1H NMR spectroscopy. Where the side chain polyethylene oxide is hexaethyleneglycolmonododecylether (DEO6). The results of concentration dependence of 1H NMR signals reveal that the metal-free phthalocyanine TDEO6-H2Pc and copper complex TDEO6-CuPc successively form the aggregates up to trimer and tetramer in the concentration range of Pc, C Pc = 10-5.5–10-1.5 M , respectively. Formation constants and chemical shifts of each aggregate were determined by non-linear regression analysis of chemical shift change. The structures of TDEO6-MPc aggregates were estimated as TDEO6-MPc is successively stacked face to face. The phthalocyanine rings in the aggregate is slipped between them, the slippage, however, is not so large. DEO6 side chains are flexible and move freely.