Thermally stable strongly fluorescent multi-stimuli responsive carbazole zwitterionic fluorophores: Alkyl chain length dependent thermofluorochromism and latent fingerprinting.

Carbazole-picoline based π-conjugated zwitterionic fluorophores, (E)-3-(4-(4-(9H-carbazol-9-yl)styryl)pyridin-1-ium-1-yl)propane-1-sulfonate (Cz-PS) and (E)-4-(4-(4-(9H-carbazol-9-yl)styryl)pyridin-1-ium-1-yl)butane-1-sulfonate (Cz-BS) were synthesized and investigated the stimuli-responsive solid-state fluorescence properties. Cz-PS and Cz-BS displayed enhanced fluorescence in the solid-state (555 and 542 nm) with the quantum yield (Φ) of 32.9 and 28.

Propeller shaped triarylamine acid: An ultra-sensitive fluorescence probe for distinguishing propanol isomers and water sensing in organic solvents.

The photophysical properties of conformationally flexible (TPA-C) and partially rigidified (Cz-C) triarylamine acids were explored in solid as well as solution state and correlated with the structure. TPA-C and Cz-C exhibited moderate solid-state fluorescence (Φ = 6.2 % (TPA-C) and 5.

Deep blue emitting dual state fluorescent triphenylamine-dicyclohexylurea derivative: Multi-stimuli responsive fluorescence switching and methanol/water sensing.

A new deep blue emissive organic fluorophore (N-cyclohexyl-N-(cyclohexylcarbamoyl)-4-(diphenylamino)benzamide (NCDPB)) was designed and synthesized, which showed strong fluorescence both in solution and solid-state. Solid-state structural analysis of NCDPB revealed non-planar twisted molecular conformation with extended hydrogen bonding between the amide functionalities. The propeller shaped triphenylamine (TPA) and non-planar cyclohexyl unit prevented close π…π stacking and produced strong deep blue emission in the solid state (λ = 400 nm, quantum yield (Φ) = 12.

Water sensitive fluorescence tuning of V-shaped ESIPT fluorophores: Substituent effect and trace amount water sensing in DMSO.

Highly sensitive nature of excited state intramolecular proton transfer (ESIPT) functionality in organic fluorophores made them potential candidates for developing environmental sensors and bioimaging applications. Herein, we report the synthesis of V-shaped Dapsone based Schiff base ESIPT derivatives (1-3) and water sensitive wide fluorescence tuning from blue to red in DMSO. Solid-state structural analysis confirmed the V-shaped molecular structure with intramolecular H-bonding and substituent dependent molecular packing in the crystal lattice.

Highly Selective Turn-on Fluorescence Sensor for Cd Ions by Tripodal Organic Ligand.

Organic fluorescence sensor for selectively detecting and quantifying toxic heavy metal ions has received significant interest due to their environmental hazards. Herein, we have designed and synthesized a simple tripodal Schiff base ligand (1) based on hydroxy-naphthaldehyde and tris(2-aminoethyl)amine (TREN) and demonstrated highly selective turn-on fluorescence sensing of Cd ions. The free ligand did not show any fluorescence in DMF.

Carbazole fluorophore with an imidazole/thiazole unit: contrasting stimuli-induced fluorescence switching, water-sensing and deep-blue emission.

Carbazole-based, π-conjugated donor-acceptor fluorophores were synthesized by integrating imidazole/thiazole units. Then, we investigated the impact of subtle structural changes on fluorescence properties. Carbazole integrated with imidazole (Cz-I) and carbazole integrated with thiazole (Cz-T) showed strong fluorescence in solution (quantum yield ( ) = 0.