Spontaneous Self-assembly of Water-soluble Porphyrins having poly(ethylene glycol) as branches: Dependence of Aggregate Properties from the Building Block Architecture

In the present paper, conformational and structural properties of aggregated structures, spontaneously formed via “self-assembly” in water solution, were studied by means of Static and Dynamic Light Scattering, UV-vis and Fluorescence Spectroscopy measurements. It was observed that small changes on the chemical structure [different position of poly(ethylene glycol) hydrophilic branches around the porphyrin unit] or molecular size (with the presence of two or three porphyrin units inside a cyclic structure) of the starting compound resulted in changes of the optical properties, size and even local architecture of the self-assembled aggregates. In particular the poly(ethylene glycol) branches position around the porphyrin cores influenced significantly the formation of H- or J-type porphyrin aggregates and their properties.