Anthracene Modified by Aldehyde Groups Exhibiting Aggregation-Induced Emission Properties

In order to get an easy way to achieve the transformation from aggregation-caused quenching luminophores (ACQphores) to aggregation-induced emission luminogens (AIEgens), we took aldehyde groups as the modifying group to decorate anthracene. The fluorescence performances of 9-anthraldehyde (AnA) and 9,10-anthracenedi-carboxaldehyde (AnDA) in solution and aggregated state were studied. We found out that the aldehyde group can transform anthracene with aggregation-caused quenching properties to AIEgen. The single-crystal structures analysis of AnA and AnDA showed that their structure characteristics are responsible for the AIE properties of AnA and AnDA. On one hand, the aldehyde group can cause steric effects to lower intermolecular pi-pi packing style in aggregated state. On the other hand, intermolecular H-bonding interactions can restrict the intramolecular rotation and suppress internal charge transfer. These results may supply a new simple method for the transformation from ACQphores to AIEgens on the point of the molecular design.