Browsing by Author "Okumuş, Veysi"

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Application of Half-Sandwich Metal-Phosphinite Compounds to Biological Activities: Determine the energies of the HOMO and LUMO levels
(Wiley Online Library, 2022) Dündar, Abdurrahman; Rafikova, Khadichakhan; Zazybin, Alexey; Güzel, Remziye; Kayan, Cezmi; Karakaş, Duygu Elma; Dündar, Abdurrahman; ISLAM, Sholpan; Okumuş, Veysi; Aydemir, Murat
Mononuclear transition metal complexes 1-(furan-2-yl)ethyldiphenyl[dichloro(η6-p-cymene)ruthenium(II)]phosphinite, (2), 1-(furan-2-yl)ethyldiphenyl[dichloro(η6-benzene) ruthenium(II)] phosphinite (3), 1-(furan-2-yl)ethyldipheny[chloro(η4-1,5-cyclooctadiene)rhodium(I)]phosphinite (4), 1-(furan-2-yl)ethyldiphenyl[dichloro (η5pentamethylcyclopentadienyl)iridium (III)] phosphinite (5) were synthesized and characterized by microanalysis, infrared, MS, and NMR spectroscopy. The biological activities of the complexes were also tested. Compounds 2 and 5 were the best complexes at DPPH radical scavenging and reducing power activity at 73.27 % and 0.41 at 200 μg/mL, respectively. The highest antimicrobial activity exhibited by complex 3 as 14 mm inhibition zone against S. aureus. All of the complexes have cleaved the DNA from the double-strand and exhibited three bands on gel electrophoresis. Moreover, cyclic voltammetry studies of the phosphinite complexes were carried out to determine the energies of the HOMO and LUMO levels as well as to estimate their electrochemical and some electronic properties.
Biological assays, electrochemical behavior, and theoretical DFT calculations of Ru(II) complexes of chiral phosphinite based based on β-amino alcohols: Transfer hyrogenation of ketones using a HCOOH/Et3N mixture
(Elsevier, 2024) Dündar, Abdurrahman; Meriç, Nermin; Ertekin Binbay, Nil; Okumuş, Veysi; Sever, M. Şerif; Belyankova, Yelizaveta; Tursynbek, Saniya; Dauletbakov, Anuar; Sarah, Bayazit; Zolotareva, Darya; Yerassyl, Kamshyger; Dündar, Abdurahman
Synthesis of two phosphinite ligands based on β-amino alcohols, in high yields has been demonstrated. When we treated [Ru(arene)(μ-Cl)Cl]2 {arene:p-cymene,benzene} with chelating phosphinite ligands, we obtained neutral Ru(II)-complexes possessing the general formula [Ru(arene)phosphiniteCl2]. The structure of the ligands and complexes was confirmed using analytical and spectroscopic techniques. The quantum chemical calculations were carried out for the ruthenium complexes at the DFT/CAM-B3LYP level of theory in gas phase. The phosphinite complexes were subjected to cyclic voltammetry studies in order to determine the energies of HOMO and LUMO levels and to estimate their electrochemical and some electronic properties. Organic complex-based memory substrates were immobilized using TiO2-modified ITO electrodes, and the memory functions of phosphinite-based organic complexes were verified by chronoamperometry (CA) and open-circuit potential amperometry (OCPA). In the present study, the antioxidant potentials of ruthenium-based p-cymene and benzene complexes through DPPH radical scavenging, metal chelating, and reducing power activities were also determined. In addition, DNA binding abilities and antimicrobial activities of these complexes against pathogenic bacteria were studied. Finally, the ruthenium complex, (2S)-1-{[(2S)-2-[(diphenylphosphanyl)oxy]propyl][(1R)-1-phenylethyl]amino}propan-2-yldiphenyl phosphinitobis[dichloro(η6-benzene)ruthenium(II)] also catalyzed asymmetric transfer hydrogenation of acetophenone with high conversion (up to 99%) and good enantioselectivity (ee up to 89 %), in the existence of formic acid and triethylamine in dichloromethane medium under air atmosphere.
Solid Phase Extraction Based on the Use of Agaricus arvensis as a Fungal Biomass for the Peconcentrations of Pb and Al Prior to Their Determination in Vegetables by ICP-OES
(ATOMIC SPECTROSCOPY, 2013) Dündar, Abdurrahman; Dündar, Abdurrahman; Özdemir, Sadin; Okumuş, Veysi
A solid phase extraction (SPE) method based on the use of a fungal biomass as sorbent was developed for the preconcentrations of Pb and Al. Agaricus arvensis was immobilized on Amberlite XAD-4 and loaded onto a column. Important parameters such as pH and flow rate of the solution, amount of biosorbent and resin, volume of sample solution, which affect the efficiency of the preconcentration procedure for Pb and Al, were optimized. The effect of possible interfering ions, i.e., Cd2+, Cu2+, Ni2+, Zn2+, Co2+, Na+, K+, Ca2+, Mg2+, and Fe2+, was investigated. Experiments on the repeatability of the solid phase column showed that the same column could be used at least 30 cycles without loss of the biosorption efficiency for the recovery of Pb and Al. The limit of detection (LOD) of Pb and Al was found to be 0.10 ng m(L-1) and 0.03 ng mL(-1), respectively. The sensitivity of ICP-OES improved 39.8-fold for Pb and 39.5-fold for Al. Linearity was obtained in the concentration range of 1.25-50.0 ng mL(-1) for Pb and 0.5-50.0 ng mL(-1) for Al. The relative standard deviation (RSD) of the method under optimum conditions was lower than 8.4% (n=5) for Pb and Al, which was validated through the analysis of certified reference tea and poplar leaves samples. The biosorption capacity of immobilized Agaricus arvensis for Pb and Al was found to be 31.2 mg g(-1) and 45.7 mg g(-1), respectively. The developed method was applied to determine the concentrations of Pb and Al in various edible vegetable samples (cucumber, okra, tomato, beans, aubergine, watermelon, zucchini, pepper, melon, lettuce, roka, purslane, scallion, cress, parsley, cabbage, sugar cane, and basil) grown along the cultivated banks of the Tigris River in Diyarbakir, Turkey.
Synthesis and Characterization of Bionanomaterials and Evaluation of Their Antioxidant, Antibacterial, and DNA Cleavage Activities
(Chemistry Select, 2021) Tarhan, Tuba; Dündar, Abdurrahman; Okumuş, Veysi; Çulha, Mustafa
In this study, the hexagonal boron nitride (hBN) (1), poly-levodopa (P-L(DP) (2), P-L(DP) coated hBN (hBN@P(L-DP)) (3), and silver nanoparticles (AgNPs) decorated hBN@P(L-DP) (hBN@P(L-DP)-AgNPs) (4) were synthesized and characterized by multiple spectroscopic techniques. Additionally, their biological properties such as antioxidant, antibacterial, and DNA cleavage activities were determined. It is worth noting that, products 3 and 4 were newly synthesized structures. The antioxidant activities of all the nanomaterials 1, 2, 3, and 4 nanomaterials were investigated using some tests such as DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and reducing power ability. Among the synthesized nanomaterials, product 2 exhibited the highest radical scavenging (64.8±1.94 %) and reducing power activity (0.61±0.017) at a concentration of 200 mg L−1. Product 4 was determined to have antibacterial activity against all three Gram-positive and three Gram-negative test bacteria. In addition, all the nanomaterials were tested for cleavage activity using pBR 322 plasmid DNA, as a result of which it was determined that only product 4 showed the ability of cleavage from both chains of DNA.