36951-35-6Relevant academic research and scientific papers
Synthesis and photophysics of extended π-conjugated systems of substituted 10-aryl-pyrenoimidazoles
Karthik, Shanmugam,Ajantha, Joseph,Nagaraja,Easwaramoorthi, Shanmugam,Gandhi, Thirumanavelan
, p. 10255 - 10266 (2016)
The synthesis of π-extended 10-aryl-pyrenoimidazoles having different substituents was realised via Ru(ii)-catalyzed oxidative annulation of 10-aryl-pyrenoimidazole with diphenylacetylene. The single crystal X-ray structure of trifluoromethyl and carboxylate substituted annulated-10-aryl-pyrenoimidazoles confirms the near coplanarity of the pyrene and imidazole moieties and the presence of twisted conformation resulting in intermolecular C-H?π interactions. The lowest energy absorption maximum becomes red-shifted characteristic to the nature of the substituent owing to the extended π-conjugation, and specifically the nitro substituent shows intense absorption in the visible region with the maximum at 440 nm. All the molecules were found to show intense fluorescence both in solution and solid states. Strikingly, 170 nm red-shifted fluorescence with a large Stokes shift ca. 7000 cm?1 for the nitro derivative, a value nearly two-fold higher than the parent compound despite its rigid polyaromatic skeleton was observed. The combination of electron rich π-conjugated aromatic systems with electron deficient substituents induces the intramolecular charge transfer interactions, which has been corroborated with the theoretical calculations.
Fluorescence Sensors for Bismuth (III) Ion from Pyreno[4,5-d]imidazole Derivatives
Chanawungmuang, Nichapa,Sukwattanasinitt, Mongkol,Rashatasakhon, Paitoon
, p. 301 - 308 (2021)
Three pyreno[4,5-d]imidazole derivatives are synthesized and evaluated as fluorescent sensors for bismuth (III) ion. The target compounds are prepared in 55–86% yields from a condensation reaction between pyrene-4,5-dione and aromatic aldehydes. The compound bearing a phenolic group can selectively detect bismuth (III) ion via fluorescence enhancement with a detection limit of 1.20?μm in CH3CN-DMSO mixture and 3.40?μm in 10% pH5 aqueous in CH3CN-DMSO mixture. The sensing mechanism involving a formation of coordination complex is investigated by UV-VIS and fluorescence titrations, 1H-NMR and the decomplexation of the bismuth complex by sulfide ion. The application of this sensor for quantitative analysis of spiked bismuth (III) ion in real water samples from two different sources is demonstrated.
