Langmuir-Blodgett films of two chiral perylene bisimide-based molecules: Aggregation and supramolecular chirality
Colloids and Surfaces A: Physicochemical and Engineering Aspects
Perylene bisimide (PBI) and its derivatives as building blocks for constructing nanostructures with functional properties have achieved considerable attention due to their applications in many fields. In this work, two chiral PBI derivatives (C6-SNPR and STDI2) molecules were utilized to prepare films by Langmuir-Blodgett (LB) technique at room temperature. Both molecules could form organized assemblies at air/water interface spontaneously by intermolecular interactions. The results of the morphological characterization showed that the facial chiral C6-SNPR molecules could self-assemble into nanoparticles with diameter about 40 nm, while the axil chiral STDI2 molecules formed irregular nanostructures at different surface pressures. The CD results showed that the self-assembled LB films of C6-SNPR were optically active while the one of STDI2 were CD silent. The relatively large steric hindrance and long spacer length in the side chains of STDI2 lead to weaker electron coupling between the neighboring molecules. Therefore, the aggregates of STDI2 exhibited CD silent in the self-assembly LB films. Moreover, the LB films of C6-SNPR showed circular polarized luminescence with relatively high glum vale about 10−3. The obtained films with excellent CD and CPL properties by LB method may provide a new clue for preparing chiral optical materials.
Circular dichroism, Stereochemistry, Nanostructures, Circularly polarized luminescence, Solid state, Materials