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排序方式: 共有107条查询结果,搜索用时 15 毫秒
71.
Guney E Kaya Y Yilmaz VT Gumus S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1171-1178
New palladium(II) and platinum(II) complexes of saccharinate (sac) with 2-(2-pyridyl)benzimidazole (pybim) have been synthesized and characterized by elemental analysis and spectroscopic techniques. From the experimental studies, these complexes were formulated as [Pd(pybim)(sac)2] (1), and [Pt(pybim)(sac)2]·4H2O (2). The ground-state geometries of both complexes were optimized using density functional theory (DFT) methods at the B3LYP level. A bidentate pybim ligand together with two N-coordinated sac ligands form the square-planar MN4 coordination geometry around the palladium(II) and platinum(II) ions. The calculated IR and UV-vis spectral data have been correlated to the experimental results. Thermal analysis data support the molecular structures of both complexes. 相似文献
72.
In this paper, we establish an algorithm for the computation of the mean residual life of a (n − k + 1)-out-of-n system in the case of independent but not necessarily identically distributed lifetimes of the components. An application for the exponentiated Weibull distribution is given to study the effect of various parameters on the mean residual life of the system. Also the relationship between the mean residual life for the system and that of its components is investigated. 相似文献
73.
Ismail??demirEmail author Sedat?Ya?ar Bekir??etinkaya 《Transition Metal Chemistry》2005,30(7):831-835
Six ruthenium-N-heterocyclic carbene complexes (2–7) have been prepared and the new compounds characterized by C, H, N analyses, 1H-n.m.r. and 13C-n.m.r. The reduction of ketones to alcohols via transfer hydrogenation was achieved with catalytic amounts of complexes (2–7) in the presence of t-BuOK. 相似文献
74.
Sulfonated N‐heterocyclic carbine‐silver (I) complexes: Synthesis,characterisation and biological evaluation
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The synthesis, characterisation and biological activity of water‐soluble Ag(I)‐NHC complexes, general formula Na[(NHC)AgCl] where NHC is a sulfonated and sterically hindered N‐heterocyclic carbene, is reported. The Ag‐NHC complexes (2a–e) were synthesised by reacting the corresponding sulfonated NHC ligands with Ag2O in the presence of NaCl or NaBr in methanol/water (1:1) solution. Synthesised silver (I)‐N‐heterocyclic carbene complexes have been characterised by NMR, micro‐analysis and HRMS spectroscopic methods. The IC50 values of these complexes were determined by a proliferation BrdU enzyme‐linked immunosorbent assay (ELISA) against HeLa (human cervix carcinoma), HT29 (human adenocarcinoma) and L929 (mouse fibroblast) cell lines. These complexes have been highlighted as promising and original platforms for building new types of metalodrug. All new water‐soluble Ag(I) complexes demonstrated remarkable cytotoxic activity against HeLa, HT29 and L929 cell lines. 相似文献
75.
We propose and demonstrate single-chip white-light-emitting diodes (WLEDs) integrated with semiconductor nanophosphors of colloidal quantum dots for high scotopic/photopic (S/P) ratio. These color conversion WLEDs achieve S/P ratios over 3.00, which exceeds the current limit of 2.50 in common lighting technologies, while sustaining sufficient levels of color rendering index. 相似文献
76.
Sedat Ture Rafig Gurbanov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):620-629
AbstractThe reactions of hexachlorocyclotriphosphazene, N3P3Cl6 (1) with 1,1,3,3-tetramethyl-guanidine (2) in (1:1:2, 1:2:4 and 1:3:6) stoichiometries in THF and dichloromethane solutions under reflux yield a total of 4 novel products: three non-geminal derivatives, N3P3Cl4[NCN2(CH3)4]2 (3), N3P3Cl3[NCN2(CH3)4]3 (4) and N3P3Cl2[NCN2(CH3)4]4 (5); and one hexa-substituted product, N3P3[NCN2(CH3)4]6 (6). The structures of 3-6 have been determined mainly by elemental analysis, MS, 31P and 1H NMR spectral data. Furthermore, thermal characteristics of the synthesized compounds 4 and 6 were evaluated using Differential Scanning Calorimetric (DSC) measurements. NMR spectroscopic data, product types and relative yields are compared with those of the previously investigated derivatives of N3P3Cl6 (1) with mono and difunctional reagents. 相似文献
77.
AbstractReactions of non-gem-hexanedioxytetrachlorocyclotriphosphazene (1) with monofunctional nucleophilic reagents, 2-(2-hydroxyethyl)thiophene (2), benzyl alcohol (3) and 1,1,3,3-tetramethylguanidine (4) were investigated. The reactions, using an excess of NaH, in THF solutions, under refluxing conditions and with 1:2?mole ratios allow the synthesis of the following novel cyclotriphosphazene derivatives: 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-[2-(2-ethoxy)hiophene]-cyclotriphosphazatriene, N3P3Cl2[O(CH2)6O-(C6H8OS)2] (5); 2,4-(hexane-1,6-dioxy)-2,4,6,6-[2-(2-ethoxy) thiophene]-cyclotriphosphazatriene, N3P3[O(CH2)6O-(C6H8OS)4] (6); 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-(methoxybenzene)-cyclotriphosphazatriene, N3P3Cl2[O(CH2)6O-(C6H5CH2O)2] (7); 2,4-(hexane-1,6-dioxy)-2,4,6,6-(methoxybenzene)-cyclotriphosphazatriene, N3P3[O(CH2)6O-(C6H5CH2O)4] (8); and 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-(1,1,3,3-tetramethyguanidine)-cyclotriphosphazatriene, N3P3Cl2[O(CH2)6O-HN-CN2(CH3)4] (9). The structures of the synthesized compounds (5–9) have been characterized by elemental analysis, TLC-MS, 1H, 13C and 31P {+1H} and {?1H} NMR spectral data. 相似文献
78.
To obtain the temperature-sensitive rate equations, a new energy level diagram of Praseodymium ion (Pr3+) in a glass host is modelled. By solving the modified rate equations, an analytical expression is presented to investigate the temperature dependence of the signal gain of a praseodymium-doped fiber amplifier (PDFA). It is seen that a change in the signal gain slightly depends on the variation of the distribution of Pr3+-ions in transitions 3F4 ↔ 3F3 with the temperature. Numerical calculations are carried out for the temperature range which is changing from −20 to +60 °C. Pr3+-doped ZBLAN fiber amplifier pumped at 1017 nm and Pr3+-doped sulfide fiber amplifier pumped at 1028 nm are selected as an application for the 1.3 μm signal wavelengths. It is also seen that the prediction of the model is in good agrement with their experimental results. 相似文献
79.
Sedat Karabulut Hilmi Namli Jerzy Leszczynski 《Journal of computer-aided molecular design》2013,27(8):681-688
Molecular structures of stable tautomers of dimedone [5,5-dimethyl-cyclohexane-1,3-dione (1) and 3-hydroxy-5,5-dimethylcyclohex-2-enone (2)] were optimized and vibrational frequencies were calculated in five different organic solvents (dimethylsulfoxide, methanol, acetonitrile, dichloromethane and chloroform). Geometry optimizations and harmonic vibrational frequency calculations were performed at DFT 6-31+G(d,p), DFT 6-311++G(2d,2p), MP2 6-311++G (2d,2p) and MP2 aug-cc-pVDZ levels for both stable forms of dimedone. Experimental FT-IR spectra of dimedone have also been recorded in the same solvents. A new approach was developed in order to determine tautomers’ ratio using both experimental and theoretical data in Lambert–Beer equation. Obtained results were compared with experimental results published in literature. It has been concluded that while DFT 6-31+G(d,p) method provides accurate enol ratio in DMSO, MeOH, and DCM, in order to obtain accurate results for the other solvents the MP2 aug-cc-pVDZ level calculations should be used for CH3CN and CHCl3 solutions. 相似文献
80.
Simge Balaban Ezgi Man Ceren Durmus Gulsah Bor Ayse Elcin Ceylan Z. Pinar Gumus Serap Evran Hakan Coskunol Suna Timur 《Electroanalysis》2020,32(3):656-665
Synthetic cannabinoids (SCs) are the large group of abused drugs and detection of them is still a challenge. Hence, new methods for analysis of SCs are being investigated. We aimed to develop a novel system for selective analysis of SCs. First, various custom‐tailored aptamers against the target SCs were selected through GO‐SELEX process. Toggling between different SC analytes during successive rounds of selection was performed to generate cross‐reactive aptamers. Then, the amino‐capped aptamers were synthesized and easily attached to the cysteamine‐covered gold electrodes. Analytical parameters and selectivity of the aptasensors were compared by using electrochemical techniques. After comparison of the analytical features and selectivity towards target analytes, one of the aptamers designated as Apta‐1 was chosen for further measurements. The aptasensor was tested by using differential pulse voltammetry technique against JWH‐018 (5‐pentanoic acid), selected as a model for SCs. The linearity and limit of detection were determined as 0.01–1.0 ng/mL and 0.036 ng/mL. Finally, sample application in synthetic urine samples was successfully performed with standard addition method, as confirmed by LC‐QTOF/MS. JWH‐018 (4‐hydroxypentyl), JWH‐073 (3‐hydroxybutyl), JWH‐250 (5‐hidroxypentyl) and HU‐210 were used to test the selectivity of the aptasensor and the system was shown to recognize all these SCs. Also other illegal drugs did not significantly interfere with the signal responses. 相似文献