Multi-stimuli responsiveness of pyrimidine bishydrazone: AIE, tuneable luminescence, white light emission, mechanochromism, acidochromism and its anticounterfeiting applications

An AIE active acidochromic pyrimidine-functionalized two-in-one fluorescent probe for selective relay detection of Al3+/Zn2+ and PPi with various detection applications

“…The probe HSAL was synthesized from inexpensive starting materials via a facile synthetic method. Schiff base condensation reaction of 4,6-dihydrazinopyrimidine 37 and salicylaldehyde in ethanolic medium under reflux conditions resulted in the formation of HSAL in good yields (Scheme 1).…”

“…The starting material 4,6-dihydrazinopyrimidine was synthesized according to a reported synthetic protocol 37 (Scheme S1, ESI †). To a stirred solution of 4,6-dihydrazinopyrimidine (0.500 g, 3.56 mmol) in 10 mL ethanol, salicylaldehyde (1.09 g, 8.91 mmol) was added and the whole reaction mixture was refluxed for 5 hours which resulted in an off-white-colored precipitate.…”

Interrogating the nature of aggregates formed in a model azine based ESIPT coupled AIE active probe: stark differences in photodynamics in the solid state and aggregates in water

“…9,12,13 Quite surprisingly, although the coupling of ESIPT with other interesting photoprocesses has been investigated thoroughly over the years, [14][15][16][17][18] the same has not been done for the coupling of AIE with ESIPT apart from basic steady state spectral studies. [19][20][21][22][23] Although sophisticated steady-state spectroscopic experiments (evolution of the steady state spectrum upon varying the percentage of water in a binary solvent system) as well as other characterization type experiments (DLS, SEM, etc.) have been conducted to prove the AIE processes in many reports, 7,24,25 no spectrodynamic studies have been conducted to identify how the ESIPT process is modulated in the aggregated form.…”

A white light emitting single halochromic hydrazine bridged bis(3-pyrrolyl BODIPY) fluorophore

“…For instance, Xiang Ma et al 19 developed bi-functional organic molecules with systematic donor–acceptor–donor type molecules 7 which generated white light emission by the transformation of the self-folded conformation to the partially folded conformation by enhancing the intramolecular charge transfer (ICT) efficiency upon tuning different excitation wavelengths, solvent polarity, temperature, and interaction with β-CD. Murugesapandian and coworkers 20 designed an organic molecule based on a D–A–D triad structure, featuring diethylaminophenol-functionalized pyrimidine bishydrazone having both excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT) properties. Remarkably, it demonstrates both reversible mechanochromism and acidochromic white light emission behavior when exposed to vapors of trifluoroacetic acid and triethylamine in both solid and solution phases.…”