Browsing by Author "FEHMI BARDAK"

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    Spectroscopic and luminescence properties of an isonicotinic acid
    (2005) FEHMI BARDAK; Nurdoğan CAN; Sözerli Şebnem Esen CAN; AHMET ATAÇ
    An isonicotinic acid N-oxide Zn(II) compound was characterized on the basis of elemental analysis. FTIR spectra of the compound and free isonicotinic acid N-oxide (INO) were recorded in the range 4000-400 $cm^{-1}$. Cathodoluminescence (CL) spectra from the $Zn(INO)_2$ complex were recorded. The luminescence data were interpreted in terms of the emission band at 470 nm. The green luminescence $(\\sim 470 nm)$ arises from $Zn^{2+}$ transition $^4T_1(^4G)\\rightarrow ^6A_1 (^6S)$. It shows a weak vibronic structure, and short lifetimes less than 150 $\\mu s$. The lifetime and intensity of the signal are temperature dependent, and the parameters are reported for the 470 nm emission line.
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    Synthesis and vibrational spectroscopic study of some metal (II) halide and tetracyanonickelate complexes of isonicotinic acid
    (2006) AHMET ATAÇ; FEHMI BARDAK
    The $M(IN)_2Ni(CN)_4$ [where M: Cu, Mn, Zn, IN: Isonicotinic acid, abbreviated to M-Ni-IN] tetracyanonickelate and some metal halide complexes with the following stoichiometries: $Cu(IN)X_2$ (X:Br,I), $Cd(IN)_2X_2$, (X:Cl,Br), and $Zn(IN)_4X_2$ (X:Br,I) were synthesized for the first time. Their FT-IR spectra were reported in the 4000-400 $cm^{−1}$ region. Vibrational assignments were given for all the observed bands. The analysis of the vibrational spectra indicates that there are some structure-spectrum correlations. For a given series of isomorphous complexes, the sum of the difference between the values of the vibrational modes of uncoordinated isonicotinic acid that were coordinated to the metal ion isonicotinic acid was investigated and found to depend on the halogen for a given metal. The proposed structure of tetracyanonickelate complexes consists of polymeric layers of $|M-Ni( CN)_4|_{\\infty}$ with the isonicotinic acid molecules bound directly to the metal (M) atoms. Certain chemical formulae were determined using the elemental analysis results.
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    Experimental and DFT-Based Investigation of Structural, Spectroscopic, and Electronic Features of 6-Chloroquinoline
    (2023) Etem Kose; FEHMI BARDAK
    This study, spectroscopic, molecular structure, and electronic features of 6-chloroquinoline were studied via experimental techniques of FT-IR, UV-Vis, 1H and 13C NMR and electronic structure with DFT/B3LYP method and 6-311++G(d,p) basis set combination. The modes of vibrational were assigned according to the potential energy distributions through the VEDA program. The gauge-invariant atomic orbital method was utilized to obtain nuclear magnetic resonance properties and chemical shifts and provided in comparison to the experimental data. Frontier molecular orbital properties and electronic absorption spectral properties, hence UV-Vis spectrum, were obtained by TD-DFT modeling. The compound of chemical reactivity was explored according to frontier molecular orbital properties, electrostatic potential surface characteristics, and analysis of atomic charge. It has been achieved that the chlorine substitution significantly alters the reactive nature of quinoline moiety.
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    2-klorokinolinin Moleküler ve Spektroskopik Özelliklerinin Kuantum Kimyasal Hesaplama Yöntemleriyle Araştırılması
    (2024) FEHMI BARDAK; Etem Kose
    Mevcut çalışma, kinolin türevlerinin aktif madde olma potansiyeli ve reaktivitesi üzerindeki klor ikame etkisini ortaya çıkarmak için 2-klorokinolin molekülünün temel moleküler özelliklerinin araştırılmasıyla ilgilidir. Buna göre FT-IR, FT-Raman, 1H ve 13C NMR spektrumlarından elde edilen deneysel sonuçlarla ve kuantum kimyasal hesaplamalarla desteklenen 2-klorokinolin için spektroskopik bir araştırmayı içermektedir. Molekülün optimize edilmiş yapısı ve enerji parametreleri, yoğunluk fonksiyonel teorisi B3LYP yöntemi 6-311++G(d,p) temel seti kullanılarak elde edildi. Molekülün titreşim özellikleri, titreşim enerji dağılımı analizi yoluyla ve moleküler modelleme yoluyla elde edilen simüle edilmiş spektrumlara uygun olarak elde edildi. Atomik Orbitalleri İçeren Gauge Yaklaşımı yöntemiyle tahmin edilen 1H ve 13C NMR kimyasal kayma özellikleri deneysel verilerle karşılaştırıldı. Ayrıca bileşiğin moleküler elektrostatik potansiyel yüzey özellikleri, atomik kısmi yükler, elektronik yörüngeler ve olası elektronik geçişler sunuldu. Klor ikamesinin 2-klorokinolin molekülünün temel özellikleri üzerinde önemli etkileri olduğu ve kimyasal reaktivitesini önemli ölçüde arttırdığı gösterilmiştir.