Unique Photophysical Behavior of Coumarin-Based Viscosity Probes during Molecular Self-Assembly

Intermolecular interactions impact self-assembly phenomena having a variety of bio/chemical, physical, and mechanical consequences. Nevertheless, the underlying mechanisms leading to a controlled stereo- and chemo-specific aggregation at the molecular level often remain elusive because of the intrinsically dynamic nature of these processes. Herein, we describe two 3-styryl coumarin molecular rotors capable of probing subtle intermolecular interactions controlling the self-assembly of a small-molecule organogelator. Complementing the characterization of the gel via circular dichroism and atomic force microscopy, thorough spectroscopic investigations on these sensors were carried out to prove their high chemical and spatial affinity toward the 3D supramolecular network. The results were further supported by molecular dynamics simulations to reveal further critical insights into the gelator's dynamic self-assembly mechanism. These sensors could potentially serve as templates to study a variety of soft-supramolecular architectures and the ways in which they assemble.