Aggregation of an octasubstituted phthalocyanine in dodecane solution

Abstract

The absorption spectra of a metal-free phthalocyanine octasubstituted with branched alkoxy chains, 2,3,9,10,16,17,23,24-octakis(3,7-dimethyloctoxy)phthalocyanine (PcH 2 (8,2)), in dodecane were analyzed in terms of monomer-dimer-trimer equilibria. The pure PcH 2 (8,2) derivative is known to have a columnar discotic mesophase at room temperature and forms a one-dimensional, self-assembled structure. In dodecane solution the same type of stacked aggregation is shown to exist with a high dimerization constant K 1 =(1.50±0.04) X 10 6 M -1 and a trimerization constant K 2 =(5.2±0.4) X 10 4 M -1