Supramolecular aggregate packing transitions as a strategy for molecular discrimination.

Inspired by the conformational rearrangements of G-protein-coupled receptors (GPCRs) during signal transduction in the human olfactory system, this study proposes and validates a molecular discrimination strategy based on packing mode transitions of organic supramolecular aggregates. We constructed four supramolecular aggregates using naphthalene diimide (NDI) derivatives as core building blocks. These aggregates enabled the discrimination of aliphatic amines, aromatic amines, and structurally similar alkaloids, including nicotine and cotinine. Our results demonstrate that subtle differences in molecular structure can induce a reduction in internal packing density and molecular order within the aggregates, and these packing changes are transduced as shifts in spectroscopic signals and variations in spectral intensity. Molecular dynamics simulations further reveal that steric hindrance and electrostatic interactions play key roles in modulating the packing modes of the aggregates, providing molecular-level support for the experimental observations. This work validates the feasibility of using structural responses of supramolecular aggregates for molecular discrimination and offers new experimental and theoretical perspectives on the structural behavior of organic aggregates upon chemical perturbation.