SUPRAMOLECULAR ASSEMBLIES OF PORPHYRINS AND PHTHALOCYANINES BEARING OPPOSITELY CHARGED SUBSTITUENTS - 1ST EVIDENCE OF HETEROTRIMER FORMATION

Mixtures of solutions of 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrins and 4,4',4'',4''-tetrasulfonated phthalocyanines in polar solvents are shown to contain well-defined supramolecular assemblies, consisting either of heterodimers or heterotrimers. The formation of these species is controlled by the affinity of the central metal ion of each chromophore for axially bound coordinating molecules. On the other hand, heteroaggregation has an influence on the axial reactivity of the chelated metals. Thus, copper and nickel phthalocyanines, which usually display no affinity for axial ligands, are able to bind strong donors such as pyridine or DMSO when involved in porphyrin-phthalocyanine heterodimers. Steric effects related to the position of the peripheral substituents have also been investigated.