MicroED Guided Structure Property Relationships in Mechanochemically Synthesized Fluorescent Cocrystals
Year: 2026
Type: preprint
Abstract: Co-crystallization offers a versatile strategy to control solid-state fluorescence in organic fluorophores. Here, we demonstrate systematic emission tuning of a pyridine-based fluorophore via mechanochemical co-crystallization with aromatic carboxylic acids differing in positional isomerism and functional group multiplicity. Dicarboxylic acid coformers induced pronounced hypsochromic shifts, whereas tri- and hexa-carboxylic acids produced bathochromic shifts, spanning emission from sapphire blue to greenish yellow. Photophysical and structural analyses revealed that O–H···N hydrogen bonding and conformational twisting in dicarboxylic acid cocrystals reduced π-conjugation, increasing the HOMO-LUMO gap. In contrast, fluorophore cocrystals with tri- and hexa-carboxylic acids enhanced electron-accepting character and donor-acceptor interactions; the resulting increased planarity and charge-transfer stabilization lead to red-shifted emission. These findings show that subtle variations in coformer structure and supramolecular interactions enable precise tuning of solid-state emission, providing a rational route to advanced luminescent materials. MicroED, together with SCXRD, plays a crucial role in establishing structure-property correlations.
Source: ChemRxiv
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221626056