Fabrication of diverse nano-architectures through the self-assembly of a naphthalene diimide derivative bearing four carbamates

Abstract

A naphthalene diimide (NDI) derivative bearing four carbamate groups (coded as: W2) was synthesised using a multistep strategy, and utilizing solvophobic effects, the self-assembly of this molecule was studied using solvent mixtures. Self-assembly led to a variety of controllable morphologies of supramolecular structures on both the micro and nanoscale. Nanobelts, nanospheres, nano-corals, microflowers and nanograss-like morphologies were obtained in DMF, MCH, CHCl₃, THF, water and MeOH solvent mixtures. UV-vis absorption, fluorescence emission spectroscopy, FT-IR and XRD gave insight into the mode of aggregation of W2 in various solvents. The polarity of the solvent mixtures used directed the self-organisation of W2 by driving the π–π stacking interaction between NDI cores, and the H-bonding between the carbamate moieties. Our studies show that the solvent polarity guides the self-assembly process during solvent evaporation leading to the formation of supramolecular nano- and microstructures under ambient conditions.