Ionoelectronics. Pillarlike Aggregates Formed via Highly Nonlinear Complexation Processes. A Light-Scattering Study

A bisphthalocyanine lutetium derivative substituted with benzo-15-crown-5 subunits, [(15C5) 4 Pc] 2 Lu ( 1 ), has been shown to form sandwich complexes with cations such as potassium ion, the complexes further form pillarlike aggregates. Light scattering studies have been carried out as a function of the ratio [K + ]/[ 1 ] in order to determine the characteristics of the aggregates. It has been demonstrated that high molar mass aggregates ( M̄ w about 10 6 ) are formed even at small [K + ]/[ 1 ] ratios, they coexist with uncomplexed monomeric [(15C5) 4 Pc] 2 Lu. The transformation from the metal-free monomer to the metal ion-containing aggregate involves a highly nonlinear two-stage complexation process. The shape of the aggregate is very probably rodlike (pillar-type structure) as indicated by the angle dependence of the light scattered.