On the role of torsional dynamics in the solid-state fluorescent properties of a new bifluorene–tetracarboxylic acid and its supramolecular assemblies: a structural and TD-DFT investigation†
Abstract
A novel butterfly-shaped tetracarboxylic acid [9,9′-methylene-bis(9-methylfluorene-2,7-dicarboxylic acid), H4L] featuring a co-facial bifluorene core was designed and synthesised. Reactions of H4L with CdII produced the luminescent supramolecular frameworks 2 and 3, with different dimensionalities and wingspans of L4−. Their solid-state emission properties were rationalised based on the torsional dynamics of the facing bifluorene units by means of X-ray diffraction analysis and TD-DFT calculations.