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Rohand T, Ben El Ayouchia H, Achtak H, Ghaleb A, Derin Y, Tutar A, Tanemura K. Design, synthesis, DFT calculations, molecular docking and antimicrobial activities of novel cobalt, chromium metal complexes of heterocyclic moiety-based 1,3,4-oxadiazole derivatives. J Biomol Struct Dyn 2022; 40:11837-11850. [PMID: 34402765 DOI: 10.1080/07391102.2021.1965031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A Schiff base, 5-(4-methylphenyl)-4-[(pyridin-2-ylmethylidene)amino]-4H-1,2,4-oxadiazole as a bidentate ligand has been synthesized by the reaction between the 4-amino-5-(4-methylphenyl)-4H-1,3,4-oxadiazole and aromatic aldehyde. The Schiff base reacted with CoCl3·6H2O and CrCl3·6H2O in ethanol to yield 1,3,4-oxadiazole complexes. The structures of synthesized ligand and their complexes have been established on the basis of their IR, Mass and 1H-NMR spectra. Electronic and geometric structures of both cobalt and chromium complexes were investigated by density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) calculations. DFT-based reactivity calculations estimated the studied system as strong electrophile and/or strong nucleophile in polar organic reactions. Moreover, most reactive sites were predicted theoretically based on the delocalized and localized indexes. The nature of Ligand-Metal chemical bonding is discussed in terms of the natural bond orbital (NBO) and QTAIM analysis. Accordingly, the metal ions such as cobalt and chromium are bidentate coordinated with the Schiff base by nitrogen atoms of imine function and pyridine, to form stable complexes. Furthermore, the chromium ions have an affinity superior to the cobalt ions towards Schiff base ligand. In addition, the results of the antibacterial activity in-vitro show that the metal complexation confers an increase in the antibacterial activity of the complexed ligand compared to the free ligand against both Gram-positive and Gram-negative bacteria with broad spectrum activity. In silico molecular docking studies of the ligands and their complexes were applied to describe the probable binding modes into the active site of Escherichia coli (E. coli) FabH and Salmonella typhimurium LT2 neuraminidase (STNA) receptors. The increase in biological activity could be attributed to the high stability of the complexes and strong affinities to bacterial enzyme receptors.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Taoufik Rohand
- Laboratoire de Chimie Analytique et Moléculaire, Département de Chimie, Université Cadi Ayyad, Faculté Polydisciplinaire Safi, Safi, Morocco
| | - Hicham Ben El Ayouchia
- Laboratoire de Chimie Analytique et Moléculaire, Département de Chimie, Université Cadi Ayyad, Faculté Polydisciplinaire Safi, Safi, Morocco
| | - Hafid Achtak
- Department of Biology, Environment and Health Research Team, Polydisciplinary Faculty, Cadi Ayyad University, Safi, Morocco
| | - Adib Ghaleb
- Laboratoire de Chimie Analytique et Moléculaire, Département de Chimie, Université Cadi Ayyad, Faculté Polydisciplinaire Safi, Safi, Morocco
| | - Yavuz Derin
- Department of Chemistry, Sakarya University, Sakarya, Turkey
| | - Ahmet Tutar
- Department of Chemistry, Sakarya University, Sakarya, Turkey
| | - Kiyoshi Tanemura
- Chemical Laboratory, School of Life Dentistry at Niigata, Nippon Dental University, Niigata, Japan
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Khomyakov PA, Andreoni W, Afify ND, Curioni A. Large-scale simulations of a-Si:H: the origin of midgap states revisited. PHYSICAL REVIEW LETTERS 2011; 107:255502. [PMID: 22243090 DOI: 10.1103/physrevlett.107.255502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Indexed: 05/31/2023]
Abstract
Large-scale classical and quantum simulations are used to generate a-Si:H structures. The bond-resolved density of the occupied electron states discloses the nature of microscopic defects responsible for levels in the gap. Highly strained bonds give rise to band tails and midgap states. The latter originate mainly from stretched bonds, in addition to dangling bonds, and can act as hole traps. This study provides strong evidence for photoinduced degradation (Staebler-Wronski effect) driven by strain, thus supporting recent work on a-Si, and sheds light on the role of hydrogen.
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