Novel Benzothiazole Boc-Phe-Phe-Bz Derivative Dipeptide Forming Fluorescent and Nonlinear Optical Self-Assembled Structures

This work explores the self-assembly and optical properties of a novel chiral, aromatic-rich Boc-Phe-Phe dipeptide derivative functionalized with a benzothiazole bicyclic ring that forms supramolecular structures. Leveraging the well-known self-assembling capabilities of diphenylalanine dipeptides, this modified derivative introduces a heterocyclic benzothiazole unit that significantly enhances the fluorescence of the resulting nanostructures. The derivative's rich aromatic character drives the formation of supramolecular structures through self-organization mechanisms influenced by quantum confinement. By adjusting the solvent system, the nanostructures exhibit tunable morphologies, ranging from nanospheres to nanobelts. The nonlinear optical properties of these self-assembled structures were studied and an estimated deff of ~0.9 pm/V was obtained, which is comparable to that reported for the highly aromatic triphenylalanine peptide.