Vessels based on cyclodextrin polymers promote aggregation induced emission

This work focuses on the use of cyclodextrin-based polymers for obtaining luminescent materials with a wide range of applications. To achieve Aggregation Induced Emission (AIE), a new strategy has been developed involving host-guest inclusion and non-inclusion complexes instead of using mixtures of good and bad solvents. Two well-known AIEgens tetraphenylethene (TPE) and tetraphenylcyclopentadiene (TPC) have been chosen along with cyclodextrin (CD)- urethane based nanosponges varying CD:linker ratios. The CD-based nanosponges were obtained by reacting β-cyclodextrin (β-CD) in DMF with the suitable cross-linking agent, hexamethylene diisocyanate (HDI), at three CD-HDI molar ratios (1:4, 1:6, and 1:8). A comprehensive morphological and photophysical characterization is undertaken. High fluorescence quantum yield (f F ) values are obtained, depending on the solvent or solvent mixture used to transport the AIEgen to the promoting host. A f F of 60% is observed for the AIEgen-CD:linker ratio of 1:4 for TPE and 81% for TPC with a ratio of 1:8. This is found to promote the AIE effect by restricting the free motion (loose bolt effect) of the phenyl rings in TPE and TPC, inside the nanosponges.