Pyrene-tethered self-assembled supramolecular system demonstrating vesicular structures and aggregation-induced emission: synthesis, assembled studies and morphology

Abstract

The emergence of aggregation-induced emission luminogens (AIEgens) has significantly stimulated the development of luminescent supramolecular materials because of their strong emissions in the aggregated state. With this inspiration, pyrene tethered Schiff base molecule, namely (Z)-1-(2,4-dinitrophenyl)-2-(pyren-1-ylmethylene), hydrazine was designed and successfully synthesized and well characterized by using proton (¹H NMR), Fourier–transform infrared (FT-IR), and electron ionization mass spectrometry (EI-MS). UV-visible absorption and emission studies have been employed to elucidate self-assembled and aggregation properties. It is shown that monomers of synthesized compounds can exhibit emission driven by assembly by forming an H-aggregate, which corresponds to its blue shift tuning to the visible region associated with the extended π-conjugation. Furthermore, to have a more profound understanding of the supramolecular assembly, TEM and confocal microscopy were utilized to verify the aggregate morphology. In both investigations, monomer aggregation into a vesicular structure with monodispersed PDI is preferred.

Graphical abstract

Pyrene tethered Schiff base molecule, namely (Z)-1-(2,4-dinitrophenyl)-2-(pyren-1-ylmethylene), hydrazine was designed and successfully synthesized. Monomer 1 demonstrating aggregation-induced emission upon increasing the gradual amount of H₂O in DMF solution of compound 1 (DMF/H₂O, 30/70 (v/v). Pictorial representation is also pasted along with TEM and confocal results of aggregate or supramolecular structures of synthesised compound.