Molecular glasses based on 1,8-naphthalimide and triphenylamine moieties as bipolar red fluorescent OLED emitters with conventional versus TADF hosting

Synthesis and Performance of Imide-Based Small Molecules Containing Carbazole Groups with AIE Properties

Here, two novel naphthalimide derivatives SNI-Cz and SNI-DCz with AIE were designed and synthesized. The correctness of the two structures was characterized by NMR and HRMS. Their crystal structures, photophysical properties, electrochemical properties, thermal stabilities, fluorescence lifetime and yields have been characterized. Photoluminescence experiments revealed that SNI-DCz had superior properties due to the D-π-A-π-D structure and sliding away stacking of molecules. SNI-DCz exhibited weak fluorescence in pure DMF, with a significant AIE effect observed in the 40% water mixture and a sharp increase in fluorescence intensity was also observed. Cyclic voltammetry and thermogravimetric analysis indicated that SNI-DCz had good electron affinity and thermal stability. The excellent properties of SNI-DCz made it a promising emitter for optoelectronics.

A 1,8-naphthalimide based chemosensor for intracellular and biofluid detection of Pd2+ ions: microscopic and anticounterfeiting studies

A naphthalimide based chemosensor (NPG), containing 1,8-naphthalimide as a fluorophore unit and pentaethylene glycol as a binding unit, has been used for the detection of Pd2+ ions in 50% HEPES buffer-DMSO (pH 7.2) solution. The NPG showed aggregation induced emission enhancement (AIEE) properties in H2O-DMSO binary mixtures (0-90%) and the CIE plot of NPG in DMSO has x = 0.152, y = 0.102 coordinates corresponding to blue colour emission with 86% colour purity. Upon addition of Pd2+ ions, NPG showed a decrease in fluorescence intensity associated with a colour change from fluorescent blue to non-fluorescent colourless solution. The lowest limit of detection for Pd2+ ions was 75 nM. The mechanism of interaction of NPG with Pd2+ ions leads to complexation induced aggregation caused quenching (ACQ) supported by DLS, SEM and AFM studies. The NPG has been successfully utilized for (i) intracellular detection of Pd2+ ions (250 μM) in live MG-63 cells; (ii) detection of Pd2+ ions in pharmaceutical (99.74 ± 0.6%), urine (98.20 ± 2.96%) and blood serum (99.17 ± 1.84%) samples and (iii) detection of Pd2+ ions using silica coated TLC strips via a contact mode method. NPG can be used as a security ink for writing letters and alphabets for anticounterfeiting applications.