Halogen Effect on Non-Conventional Organogel Assisted by Balanced π-π Interaction

Triphenylamine-functionalized anthracene derivatives bearing no alkyl chains or amide units (ADIPA and Br-ADIPA) are synthesized in a straightforward manner. Among these two compounds, Br-ADIPA could form stable gel in organic solvents, but ADIPA cannot gelate any conventional solvents under the tested conditions. In order to disclose the supramolecular self-assembly of Br-ADIPA gel, a series of characterizations were performed, which indicated that it might self-assemble into aggregates which do not involve pi-pi stacking between anthracene chromophore in the gel state, and intermolecular pi-pi interactions between phenyl rings on triphenylamine moieties are essential driven forces for its gelation. Interestingly, the self-assemblies of these two compounds calculated using Polymorph software well matched the characterization results. It revealed that a one-dimensional molecular packing was promoted by multiple intermolecular pp interactions between triphenylamine units in Br-ADIPA, and the bromine atom played important role in its balanced intermolecular pi-pi interactions. In comparison, these supramolecular forces in ADIPA provided a three-dimensional structure.