Pick and Choose the Coordinated Metal Ion to Tune the Porphyrin Supramolecular Chirogenesis

The solvent-driven aggregation of metalloporphyrin derivatives, bearing an L- or D-prolinate appendage, results in the stereospecific formation of chiral species that are strictly influenced by the aminoacid chirality and, above all, by the metal axial coordination capability. The Pd porphyrin derivatives self-assemble in hydroalcoholic mixtures in fractal-like suprastructures, displaying intense, specular dichroic bands and peculiar UV-Vis spectral features, accounting for the formation of J-type aggregates of complex morphology. Spectroscopic and kinetic studies gave important information on the aggregation process, allowing for a comparison with previously reported systems achieved from the free base and Zn derivatives in the same aggregative conditions. Analyzing the self-aggregation process for the three porphyrin derivatives highlights the remarkable influence of porphyrin inner core features on the chirogenesis of the final systems, revealing an easy tunability of the asymmetry of the assemblies upon metal choosing.Self-assembly of prolinated metalloporphyrin enantiomers in hydroalcoholic media gives stereospecific suprastructures with tunable chiroptical and morphological properties depending on the porphyrin core features. This is here shown by comparing the aggregation behavior of Zn and Pd complexes and the porphyrin free base in the same experimental conditions. image