Unveiling Morphology Evolution and Key Intermediates in the Self-Assembly of Amino Acid-Naphthalene Diimide Triads

Abstract

Precise control over molecular self-assembly is essential for constructing sophisticated architectures from simple building blocks. This demands a fundamental understanding of how chemical structure dictates morphological evolution, as well as the identification of key intermediates during assembly. Here, we study the self-assembly of an L-phenylalanine methyl ester-functionalized naphthalene diimide (NDI) triad and its alkyl chain-spaced analogue, which form millimeter-scale sheets and fibers, respectively, in chlorinated solvents. We elucidate the detailed pathways of morphological evolution and identify critical intermediates governing the process. NMR titration experiments and computational studies reveal the driving forces behind assembly, while photophysical characterization and hydrogen evolution assessments demonstrate functional implications. Our findings highlight how subtle structural modifications steer long-range molecular organization by modulating intermolecular interactions, ultimately dictating material performance.