No abstract

No abstract

No abstract

No abstract

The new 3H-imidazo[4,5-a]acridine-11-carbonitriles were prepared from the reaction of 1-alkyl-5-nitro-1H-benzoimidazoles with 2-(4-methoxyphenyl)acetonitrile and benzyl cyanide by nucleophilic substitution of hydrogen in high yields. Physical spectral and analytical data have confirmed the structures of the synthesized dyes. The optical and solvatochromic properties of these compounds were investigated and the results showed that they show very interesting photophysical properties. Density functional theory (DFT) calculations of fluorescent dyes were performed to provide the optimized geometries and relevant frontier orbitals. Furthermore, intra- and intermolecular interactions in fluorescent imidazo[4,5-a]acridines were evaluated by AIM (Atoms in Molecules) analysis.

No abstract

New fluorescent heterocyclic ligands were synthesized by the reaction of 8‐(4‐chlorophenyl)‐3‐alkyl‐3H‐imidazo[4',5':3,4]benzo [1,2‐c]isoxazol‐5‐amine with p‐hydroxybenzaldehyde and p‐chlorobenzaldehyde in good yields. The coordination ability of the ligands with Fe3+ ion was examined in an aqueous metanolic solution. Schiff base ligands and their metal complexes were characterized by elemental analyses, IR, UV–vis, mass, and NMR spectra. The optical properties of the compounds were investigated and the results showed that the fluorescence of all compounds is intense and their obtained emission quantum yields are around 0.15 – 0.53. Optimized geometries and assignment of the IR bands and NMR chemical shifts of the new complexes were also computed by using density functional theory (DFT) methods. The DFT‐calculated vibrational wavenumbers and NMR chemical shifts are in good agreement with the experimental values, confirming suitability of the optimized geometries for Fe(III) complexes. Also, the 3D‐distribution map for HOMO and LUMO of the compounds were obtained. The new compounds showed potent antibacterial activity and their antibacterial activity (MIC) against Gram‐positive and Gram‐negative bacterial species were also determined. Results of antibacterial test revealed that coordination of ligands to Fe(III) leads to improvement in the antibacterial activity.

An increasingly wide variety of fluorescent compounds is used in biotechnology, genomics, immunoassays, array technologies, imaging, and drug discovery. Therefore, synthesis of fluorophores with novel structural features can be interesting and useful in various fields. In this paper, four new fluorescent heterocyclic compounds with high quantum yields are introduced. These new fluorophores are synthesized in moderate to high yields via regioselective nitration of 3-alkyl-8-(4-chlorophenyl)-3 H-imidazo[4',5':3,4]benzo[c]isoxazoles. The latter compounds are obtained from the reaction of 1-alkyl-5-nitro-1 H-benzoimidazoles with (4-chlorophenyl)acetonitrile in basic MeOH solution. Physical spectral (UV-vis, IR, (1)HNMR, (13)C NMR, NOESY and fluorescence) and analytical data have established the structures of synthesized compounds. The fluorescence properties of new fluorescent heterocyclic compounds are studied. The fluorescence of all compounds is very intense and fluorescence quantum yields are high (> 0.52). Density functional theory (DFT) calculations are performed to provide the optimized geometries, relevant frontier orbitals and the prediction of (1)H NMR chemical shifts for confirming the exact structure of fluorescent compounds. Calculated electronic absorption spectra were also obtained by time-dependent density functional theory (TD-DFT) method.