title: The new Schiff base 4-[(4-Hydroxy-3-fluoro-5-methoxy-benzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one: experimental, DFT calculational studies and in vitro antimicrobial activity.
abstract: The synthesized Schiff base, 4-[(4-Hydroxy-3-fluoro-5-methoxy-benzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one (I), has been characterized by (13)C NMR, (1)H NMR, 2D NMR ((1)H-(1)H COSY and (13)C APT), FT-IR, UV-vis and X-ray single-crystal techniques. Molecular geometry of the compound I in the ground state, vibrational frequencies and chemical shift values have been calculated by using the density functional method (DFT) with 6-311++G(d,p) basis set. The obtained results indicate that optimized geometry can well reflect the crystal structural parameters. The differences between experimental and calculated results of FT-IR and NMR have supported the existence of intermolecular (O-H⋯O type) and intramolecular (C-H⋯O type) hydrogen bonds in the crystal structure. Molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO) and electronic absorption spectra were carried out at B3LYP/6-311G++(d,p). HOMO-LUMO electronic transition of 3.92eV is due to contribution of the bands the n→π∗. The antimicrobial activity of the compound I was determined against the selected 11 bacteria and 8 fungi by microdilution broth assay with Alamar Blue. In vitro studies showed that the compound I has no antifungal effect for selected fungal isolates. However, the compound I shows remarkable antibacterial effect for the bacteria; Streptococcus pneumoniae, Haemophilus influenzae and Enterococcus faecalis.
authors.affiliation: Department of Science Education, Ondokuz Mayıs University, 55139 Kurupelit, Samsun, Turkey.
authors.forename: Nazan Ocak
authors.initials: NO
authors.lastname: İskeleli
authors.affiliation: Department of Biophysics, Faculty of Medicine, Giresun University, 28100 Giresun, Turkey. Electronic address: yeldabingol_55@hotmail.com.
authors.forename: Yelda Bingöl
authors.initials: YB
authors.lastname: Alpaslan
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Giresun University, 28100 Giresun, Turkey.
authors.forename: Şahin
authors.initials: Ş
authors.lastname: Direkel
authors.affiliation: Department of Chemistry, Faculty of Science and Arts, Ordu University, Cumhuriyet Campus, 52200 Ordu, Turkey.
authors.forename: Aliye Gediz
authors.initials: AG
authors.lastname: Ertürk
authors.affiliation: Atatürk Vocational High School, Gazi University, 06760 Çubuk, Ankara, Turkey.
authors.forename: Nevin
authors.initials: N
authors.lastname: Süleymanoğlu
authors.affiliation: Department of Middle Education, Educational Faculty, Ondokuz Mayıs University, 55139 Kurupelit, Samsun, Turkey.
authors.forename: Reşat
authors.initials: R
authors.lastname: Ustabaş
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D018360:Crystallography, X-Ray; D004583:Electrons; D005658:Fungi / Q000187:drug effects; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011720:Pyrazoles / Q000737:chemistry*; D047069:Pyrazolones / Q000737:chemistry*; D011789:Quantum Theory; D012545:Schiff Bases / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014732:Vibration
chemical_list: C000602373:4-((4-hydroxy-3-fluoro-5-methoxybenzylidene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one; D000890:Anti-Infective Agents; D000935:Antifungal Agents; D011720:Pyrazoles; D047069:Pyrazolones; D012545:Schiff Bases
keywords: Antibacterial and antifungal activity; Crystal structure; DFT calculations; Electronic absorption spectra; FT-IR and NMR spectroscopy; Schiff base