Excited state intramolecular proton transfer induced fluorescence in triphenylamine molecule: Role of structural conformation and reversible mechanofluorochromism

Recent advances in excited state intramolecular proton transfer mechanism-based solid state fluorescent materials and stimuli-responsive fluorescence switching

Substitutional change and controlling intra and intermolecular interactions of ESIPT molecules resulted in realizing multifunctional fluorescence properties.

Symmetrical and unsymmetrical thiazole-based ESIPT derivatives: the highly selective fluorescence sensing of Cu2+ and structure-controlled reversible mechanofluorochromism

Excited state intramolecular proton transfer (ESIPT) process-based organic fluorophores provide an opportunity to develop large Stokes-shifted multifunctional fluorescence systems for light emitting, chemosensing and bioimaging applications.

Triphenylamine-based stimuli-responsive solid state fluorescent materials

Molecular engineering of triphenylamine (TPA) units produced multi-stimuli-responsive solid state fluorescent materials.

ESIPT-active multi-color aggregation-induced emission features of triphenylamine–salicylaldehyde-based unsymmetrical azine family

A new family of ESIPT and AIE-active triphenylamine-appended unsymmetrical azine derivatives is reported.

Synthesis of Strongly Fluorescent Imidazole Derivatives: Structure Property Studies, Halochromism and Fluorescent Photoswitching

New series of methoxy and hydroxyl group substituted triphenylamine (TPA)-imidazole fluorescent molecules (5-(diphenylamino)-2-(1H-phenanthro[9,10-d]imidazol-2-yl)phenol (1), 5-(diphenylamino)-2-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenol (2), 5-(diphenylamino)-2-(4,5-diphenyl-1H-imidazol-2-yl)phenol (3), 5-(diphenylamino)-2-(1,4,5-triphenyl-1H-imidazol-2-yl)phenol (4), N-(3-methoxy-4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-N-phenylbenzenamine (5), N-(3-methoxy-4-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-N-phenylbenzene amine (6), and N-(3-methoxy-4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)-N-phenylbenzenamine (7)) have been synthesized that exhibited strong solution fluorescence and molecular structure and conformation controlled fluorescence photoswitching, solid state fluorescence and halochromism. Hydroxyl substituted molecules (1-4) showed moderate to strong fluorescence in solution depend on solvent polarity and very weak solid state fluorescence. Methoxy substituted molecules (5-7) displayed strong fluorescence both in solution and solid state. Solid state structural studies revealed strong intramolecular H-bonding in the crystal lattice. Interestingly, highly twisted structure (6) showed rare light induced reversible fluorescence switching in CHCl₃. The observation of isobestic point in time dependent fluorescence photoswitching studies indicated structural isomer conversion. Further, acid sensitive imidazole nitrogen has been made use to demonstrate solid state fluorescence switching via halochromism. Thus the present studies attempted to develop new fluorescent molecules and establish structure-property relationship for designing fluorescence switching materials. Graphical Abstract Molecular structure controlled solid state fluorescence, halochromism and a rare fluorescence photoswitching in chloroform have been observed with triphenylamine-imidazole derivatives.

Self-agglomerated crystalline needles harnessing ESIPT and AIEE features for the ‘turn-on’ fluorescence detection of Al3+ ions

We report the synthesis of probe 2 for the fluorescence “turn-on” detection of Al³⁺ ions in CH₃OH.

Unusual fluorescent photoswitching of imidazole derivatives: the role of molecular conformation and twist angle controlled organic solid state fluorescence

Triphenylamine-imidazole molecules exhibited unprecedented light induced fluorescence switching via conformational change.