Inorganic nanostructured templates for porphyrin J aggregates growth

Organic- inorganic hybrid nanocomposites are widely studied in several scientific fields due to theemergence of new properties in terms of chemical an spectroscopic behavior, coming from the conjunction of different building blocks. In virtue of their interesting spectroscopic properties and their ability to form self-assembled structures, porphyrins represent interesting candidates as organic building blocks to realize hybrids nanocomposite materials. In particular, tetrakis (4- sulphonatophenyl) porphyrin (TPPS4) is able to form self- assembled J- aggregates, with different shape and size, whose growth is closely related to the experimental conditions (i.e. pH, reactant concentrations, addition of salt and templating agents) [1-2]. In this work, the aggregation process of TPPS4 in presence of different inorganic nanostructured materials is examined. As first example, we have chosen gold nanorods and clusters composed of ten metal atoms (Au10). In both cases, formationof J aggregates can be revealed in solution at moderately acidic pH. Furthermore, on a glass surface the presence of Au10 and the acidity of the medium trigger the formation of a metallic self- assembled layer composed of gold nanoparticles and porphyrin aggregates. As second example in the class of 2D materials, carbon nanotubes functionalized with amine groups have been examined. The length of the spacer chains bearing the amino moiety plays an important role in porphyrin aggregationprocess. SPION nanoparticles have been also examined. All the investigated nanocomposites have been examined by detailed spectroscopic and morphologic characterization.