Synthesis, spectroscopic characterization and DFT calculations of a new highly fluorescent heterocyclic system: imidazo[4,5-a]quinindoline

Abstract

New N-alkyl-substituted heterocyclic system imidazo [4,5-a]quinindolines (imidazo[4,5-f]-indolo[2,3-b]quinolines) were synthesized by one pot reaction of 1-alkyl-5-nitro-1H-benzimidazole with 2-(1-alkyl-1H-3-indolyl)acetonitrile in basic media via the nucleophilic substitution of hydrogen and concomitant cyclisation in good yields. Physical spectral (UV-vis, IR, NMR and fluorescence) and analytical data have established the structures of synthesized compounds. The fluorescence properties of these new heterocyclic compounds were studied. The fluorescence of all compounds was very intense and fluorescence quantum yields were very high (> 0.70). Solvent effects on absorption and emission spectra of these dyes have also been studied; the absorption and emission bands in polar solvents undergo a red shift. Density function theory (DFT) calculations of one structure by using the B3LYP hybrid functional and the 6-311+G(d,p) basis set to provide the relevant frontier orbitals were also performed.

Analysis of Different Bioactive Compounds Conferring Antimicrobial Activity from Lactobacillus plantarum and Lactobacillus acidophilus with Gas Chromatography-Mass Spectrometry (GC-MS)

“…Other compounds as Isopropyl Myristate possess antioxidant and antibacterial properties (Faridha Begum et al, 2016). Furthermore, Rahman et al (2014) showed that 9-Hexadecenoic acid had antimicrobial properties.Several studies showed that Quinindoline had Antibacterial activity (Sokhanvar and Pordel, 2014;Pordel et al, 2016). Quinindolines are a group of synthetic analogs of the natural alkaloid neocryptolepine.…”

“…The quinindoline derivatives also revealed antimicrobial, antimuscarinic, antiviral, and cytotoxic potential. A combination of the quinindoline moiety with the imidazole nucleus may enhance optical and biological properties (Sokhanvar and Pordel., 2014).…”

Synthesis, electrochemical, photophysical, and photovoltaic properties of new fluorescent compounds: 3 H ‐benzofuro[2,3‐ b ]pyrazolo[4,3‐ f ]quinoline

“…In our earlier research works, some new fluorescent heterocyclic compounds have been synthesized with pentacyclic aromatic skeleton featuring indole, 4‐pyridinecarbonitrile, and benzimidazole or indazole systems as the key ingredients 33,34 . In the present study, which is conducted as continuation of our investigations on synthesizing new heterocyclic dyes as organic photosensitizers in DSSCs, 35,36 we have aimed at a synthesis of 3 H ‐benzofuro[2,3‐ b ]pyrazolo[4,3‐ f ]quinolines as novel fluorophores as high‐performance organic photosensitizers.…”