A facile synthesis of amphiphilic N-glycosyl naphthalimides and fabrication of flexible semiconductors using molecular self-assembly

Abstract

Using natural processes as a guiding tool, the scientific community is actively involved in achieving substantial advances at the interface of supramolecular chemistry and materials design. In this paper, we have synthesized a series of amphiphilic N-glycosyl naphthalimides using environmentally benign protocols in good yields. For the first time, an exclusive formation of β-anomeric product using ammonium sulfate catalyst, an FDA approved GRAS chemical, has been thoroughly investigated. To explore the potential of N-glycosyl naphthalimides in the field of supramolecular materials, molecular self-assembly studies were systematically performed in a wide range of solvents and they were found to form a hydrogel, organogel and oleogel. The existence of molecular level interactions and assembly pattern were identified using FT-IR, NMR, SAXRD, UV-vis and fluorescence spectral methods and a suitable assembly mechanism was proposed. The morphology of the supramolecular architecture with respect to the molecular structure was identified using optical microscopy and scanning electron microscopy. Rheological studies clearly disclose the strength of soft materials and processability. Conductivity measurements on assembled thin films developed by drop casting of N-glycosyl naphthalimides reveal the semiconducting behaviour. Interestingly, a highly flexible semiconducting material derived by anchoring of a gelator on cotton fabric through hydrogen bonding displayed enhanced conducting properties compared to the assembled thin film. The demonstrated flexible organic semiconducting material obtained via a more sustainable pathway would provide an opportunity to fabricate green electronics.