Browsing by Author "Zengin, Huseyin"

Now showing 1 - 2 of 2

2,6-Bis((e) and Its Metal(Ii) Complexes: Synthesis, Spectroscopy, Biological Activity, and Photoluminescence Features
(Wiley-v C H verlag Gmbh, 2013) Gulcan, Mehmet; Zengin, Huseyin; Celebi, Metin; Sonmez, Mehmet; Berber, Ismet
The preparation, characterization, magnetic measurements, antimicrobial activity, and photoluminescence properties of a number of metal complexes with a Schiff base ligand derived from 2, 6-diformyl-4-methylphenol and 1-amino-5-benzoyl-4-phenyl-1H-pyrimidine-2-thione are reported herein. UV/Vis spectra and magnetic measurements infer square planar stereochemistry for Pd-II and Pt-II complexes, and octahedral arrangement for the other metal complexes. The compounds results in intense emission (where (max) = 402 nm) upon irradiation by UV light. The photoluminescence quantum yields and long excited-state lifetimes of the ligand and its complexes were calculated as 42% and 3.94 ns, respectively. The photoluminescence intensities and quantum yields of metal complexes changed upon complexation with various metal ions. The ligand and its complexes are of interest as organic emitting materials for electroluminescent devices. The complexes were additionally evaluated for in vitro the antimicrobial activity against bacterial and fungal strains. While Cu-II, Co-II, and Pt-II complexes have good antifungal efficiency against yeast (MICs, 80 gmL(-1)), only the complex [Cu(L)(AcO)]4H(2)O had effective and selective antimicrobial activity against all tested microorganisms with MIC values in the range of 40-80 gmL(-1), except for E. coli ATCC 4230. This study suggests that the complex [Cu(L)(AcO)]4H(2)O may be a new potential antimicrobial substance towards bacteria and fungi.
Wear Resistance and Tribological Properties of Gnps and Mwcnt Reinforced Alsi18cunimg Alloys Produced by Stir Casting
(Elsevier Sci Ltd, 2021) Turan, Muhammet Emre; Aydin, Fatih; Sun, Yavuz; Zengin, Huseyin; Akinay, Yuksel
The present work aims to produce Multiwalled Carbon Nanotube (MWCNT) and Graphene Nanoplatelets (GNPs) reinforced AlSiCuNiMg alloy matrix composites via stir casting. The wear resistance and tribological performances of produced materials are examined by steel balls in dry sliding conditions under loads of 10 N, 20 N, and 40 N. The composites were produced by the combination of semi powder metallurgy and stir casting techniques and then a solid-solution + aging process was applied. The microstructures and phase-type of all specimens were examined by Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). The results of this study show that the wear rates of the matrix decreased significantly with the addition of GNPs and MWCNTs reinforcements. When sliding speed increased, wear rates for all produced samples decrease. Graphene reinforced composite exhibited the best tribological behavior among the prepared samples. The design of test conditions and the analysis of output responses were studied by statistical analysis of Taguchi array, analysis of variance (ANOVA) and regression models. ANOVA indicated that the wear rate was mainly affected by material content followed by sliding speed and applied load. The wear mechanisms were identified by characterizations of worn surface, wear debris and counterface material.