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    New Bi-Nuclear Nickel(II) Complex-Based Salen Schiff Base: Synthesis, Crystal Structure, Spectroscopic, Thermal, and Electrical Investigations
    (Mdpi, 2022) Es-Sounni, Bouchra; Haily, El Mehdi; Nakkabi, Asmae; Bakhouch, Mohamed; Bejaoui, Linda; Kaya, Savas; El Yazidi, Mohamed
    In this study, a new bi-nuclear nickel complex [Ni2HL2(EtOH)(2)](Cl)(EtOH) of a Schiff base ligand, 2-[3-[2-hydroxybenzylideneamino]propyliminomethyl]phenol, was synthesized and characterized using UV/Vis, IR, HRMS, and TGA/DTA analysis. The molecular structure of the obtained complex was corroborated by the single crystal X-ray diffraction technique. It was found in the complex that two molecules of the ligand coordinate with two nickel atoms through azomethine-N and phenoxy-O, resulting in 6-coordinate distorted octahedral geometry, in which two ethanol molecules occupy the axial positions. The dielectric and electrical properties of the obtained samples were studied by impedance spectroscopy at different frequencies (from 1 Hz to 1 MHz) in the temperature range 298-343 K. It is found that the electrical conductivity of the Ni(II) complex is lower than that of the free ligand H2L, suggesting that the complexation traps the charge carriers contained in the ligand.
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    Synthesis, crystal structure, Hirshfeld surface analysis and DFT calculations of 2, 2, 2-tribromo-1-(3,5-dibromo-2-hydroxyphenyl)ethanone
    (Elsevier, 2022) Brahmia, Ameni; Bejaoui, Linda; Rolicek, Jan; Hassen, RachedBen; Serdaroglu, Goncagul; Kaya, Savas
    A novel derivative 2, 2, 2-tribromo-1-(3,5-dibromo-2-hydroxyphenyl) ethanone was synthesis by 3-acetyl-4-hydroxycoumarin and dibromide. The structural properties of the synthesized compound have been exploited with the aid of single-crystal X-ray crystallographic studies and infrared spectrometry. The compound crystallizes in the monoclinic system with space group P2(1)/c. A comparative study between the novel brominated compound synthesized and the brominated coumarin derivative is presented. The optimized DFT geometries (B3PW91/6-311 G (2df, p)) and the spectral simulations of two derivatives compared agree well with the experimental data. Hirshfeld's analysis revealed the importance of Br center dot center dot center dot Br (40%) and Br center dot center dot center dot H/H center dot center dot center dot Br (19%) of the total surface contacts in the molecular stack. The contacts O center dot center dot center dot H/H center dot center dot center dot O have a significant contribution for the brominated coumarin (C2) of 26.1% of SH compared to the brominated cycle (C1) 9.7%. (C) 2021 Published by Elsevier B.V.
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    Synthesis, crystal structure, hirshfeld surface analysis, spectroscopic, biological and first-principles studies of novel aminocoumarins
    (Elsevier, 2020) Bejaoui, Linda; Brahmia, Ameni; Marzouki, Riadh; Dusek, Michal; Eigner, Vaclav; Serdaroglu, Goncagul; Kaya, Savas
    Two novel aminocoumarins 3-(1-(2 aminophenylamino) ethylidene)chromene-2,4-dione, noted (1) and 3-(1-(2-1-(2, 4-dioxochromene-3-ylidene) ethylamino)phenylamino) ethylidene) chromene-2,4-dione,noted (2), were synthesized from 3-acetyl-4-hydroxycoumarin and ortho-phenylenediamine in absolute ethanol and characterized by spectroscopies methods (FT-IR, UV-vis and fluorescence). The crystal structures of the mentioned compounds were solved from single-crystal diffraction data at low temperature. The compound (1) crystallizes in the orthorhombic system with space group Iba2 while (2) is monoclinic with space group P(2)1/c . Hirshfeld surface analysis indicates the presence of the pi-pi stacking in the aminocoumarin structures with the contribution of 7.8% for (1) and 8.7% for (2) of the total Hirshfeld area. The optimized DFT geometries (B3PW91/6-311 G (2df, p)) and the spectral simulations agree well with the experimental data. Theoretical reactivity behavior was assessed, taking into account HOMOLUMO diagrams and Molecular Electrostatic Potential maps. The two aminocoumarins derivatives have fluorescence properties. Analysis of the photoluminescence spectra shows that the emission intensity is high for the solutions of the two compounds in polar aprotic solvents (DMSO, DMF). The aminocoumarins were monitored for antimicrobial activity using the disk diffusion method. The coumarin (1) is effective against S. aureus (gram-positive bacteria) and S. typhy (gram-negative bacteria), but the coumarin (2) showed markedly weak antibacterial activity. (C) 2020 Elsevier B.V. All rights reserved.