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71.
Hande Petek Çiğdem Albayrak Nazan Ocak İskeleli Erbil Ağar İsmet Şenel 《Journal of chemical crystallography》2007,37(4):285-290
The single crystal X-ray diffraction analysis of the title compound, C14H20N2O3, reveals that the structure is adapted to its zwitterionic form and centrosymmetric dimers are formed by N+–H···O− type ionic weak hydrogen bonds in the crystal structure. The title compound crystallizes in the triclinic space group P−1 with a = 5.9255(13) ?, b = 9.853(3) ?, c = 12.248(3) ?, α = 101.793(19)°, β = 94.941(17)°, γ = 104.36(2)°, Z = 2, Dx = 1.308 g/cm3, μ (Mo-Kα) = 0.092 mm−1. The structure was solved by direct methods and refined to a final R = 0.0371 for 2183 reflections with I > 2σ (I). The crystal structure is stabilized by N+–H···O− type intra-molecular hydrogen bonds and N+–H···O− type packing interactions referred to as weak hydrogen bonds. To elucidate conformational flexibility of the title molecule,
the selected torsion angle is varied from −180° to +180° in every 10° separately and then molecular energy profile is calculated
and construed. In addition, charge-population analysis of the crystallographically observed structure confirms its zwitterionic
form. 相似文献
72.
Mevlut Albayrak Yucel Kadioglu Mehmet Emrah Yaman Onur Senol Elif Oral 《Biomedical chromatography : BMC》2019,33(4)
Olanzapine is an atypical antipsychotic drug from the thienobenzodiazepine family which displays efficacy in patients with schizophrenia and related psychoses. A novel LC/MS method was developed and validated for determination of olanzapine in schizophrenia patients' plasma. A liquid–liquid extraction procedure was carried out using 5 mL diethyl ether–diisopropyl ether mixture (1:1, v/v). Average recovery of the extraction procedure was 94.8%. Chromatographic separation was performed on reversed‐phase C18 column (250 × 2.0 mm, 5 μm) using mixture of deionized water (trifluoro acetic acid 0.1%)–acetonitrile (20:80, v/v) as mobile phase at a flow rate of 1 mL/min. Irbesartan was used as internal standart and total run time was 2.5 min. Mass spectrometric analysis were carried out in selective‐ion montoring mode, and detected olanzapine at m/z 313.1 and IS at m/z 429.4 in all forms of the ions. The calibration curve of olanzapine was linear in the range 2–300 ng/mL (r2 > 0.9993). The interday and intraday precisions (RSD) were <7.55%, and accuracy was >7.59% (n = 6). The proposed study was successfully validated with respect to the US Food and Drug Administration guidelines. 相似文献
73.
Erhan Albayrak 《中国物理 B》2012,21(6):67501-067501
The random crystal field(RCF) effects are investigated on the phase diagrams of the mixed-spins 1/2 and 3/2 Blume-Capel(BC) model on the Bethe lattice.The bimodal random crystal field is assumed and the recursion relations are employed for the solution of the model.The system gives only the second-order phase transitions for all values of the crystal fields in the non-random bimodal distribution for given probability.The randomness does not change the order of the phase transitions for higher crystal field values,i.e.,it is always second-order,but it may introduce first-order phase transitions at lower negative crystal field values for the probability in the range about 0.20 and 0.45,which is only the second-order for the non-random case in this range.Thus our work claims that randomness may be used to induce first-order phase transitions at lower negative crystal field values at lower probabilities. 相似文献
74.
The critical behaviors of the trilayer Bethe lattice in the form of spin-(1/2,3/2,1/2) with the exterior two layers consisting of spin-1/2 and the interior one having only spin-3/2 Ising spins are studied in terms of the recursion relations with either ferromagnetic or antiferromagnetic bilinear exchange interactions between the nearest-neighbor spins. The ground-state phase diagrams are calculated and it is found that the model presents six different ground state phase configurations. The thermal variations of the order-parameter and free energy are investigated, therefore, topologically different phase diagrams of the model are obtained. It is found that the model exhibits second- and first-order phase transitions, tricritical and bicritical points for the values of the coordination numbers q=3, 4 and 6 and, the reentrant behavior for q=4 and 6, respectively. 相似文献
75.
Albayrak Ç Kaştaş G Odabaşoğlu M Frank R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,81(1):72-78
In this study, the molecular structure and spectroscopic properties of (E)-5-(diethylamino)-2-[(4-methylphenylimino)methyl]phenol were characterized experimentally by X-ray diffraction, FT-IR and UV-vis spectroscopic techniques and computationally by DFT method. It is concluded on the basis of X-ray diffraction and FT-IR analyses that the title compound exists in enol form in the solid state. UV-vis spectra of the title compound were recorded in different organic solvents to investigate the dependence of tautomerism on solvent types. The tautomerism-solvent relation was also studied by computational methods to have more insight on structural properties. The geometry optimization of the title compound in gas phase was performed by using DFT (B3LYP) method with 6-311G(d,p) basis set. The geometry optimizations in solvent media were carried out at the same theory level by the polarizable continuum model (PCM). In the calculation of excitation energies, TD-DFT calculations were carried out in both gas and solution phases. The computational investigation of non-linear optical properties indicates that the title compound has a good second order nonlinear optical property. The thermodynamic properties were obtained in the range of 100-500 K. 相似文献
76.
Hande Petek Çiğdem Albayrak Mustafa Odabaşoğlu İsmet Şenel Orhan Büyükgüngör 《Structural chemistry》2010,21(4):681-690
The crystal and molecular structures of an o-hydroxy Schiff base derivative, (E)-2-ethoxy-6-[(2-methoxyphenylimino)methyl]phenol, have been determined by single crystal X-ray diffraction analyses at 296 and 100 K. The results from temperature-dependent structural analysis regarding the tautomeric equilibrium of the compound were interpreted with the aid of quantum chemical calculations. To clarify the tautomerization process and its effects on the molecular geometry, the gas-phase geometry optimizations of two possible tautomers of the title molecule, its OH and NH form, were achieved using DFT calculations with B3LYP method by means of 6-31 + G(d,p) basis set. In order to describe the potential barrier belonging to the phenolic proton transfer, nonadiabatic Potential Energy Surface (PES) scan was performed based on the optimized geometry of the OH tautomeric form by varying the redundant internal coordinate, O–H bond distance. The Harmonic Oscillator Model of Aromaticity (HOMA) indices were calculated in every step of the scan process so as to express the deformation in the aromaticities of principal molecular moieties of the compound. The results show that there is a dynamic equilibrium between the aromaticity level of phenol and chelate ring and furthermore π-electron coupling affecting overall molecule of the title compound. Charge transfer from phenol ring to pseudo-aromatic chelate ring increases with increasing temperature, whereas π-electron transfer from chelate ring to anisole ring is decreased as temperature increases. The most strength intramolecular H-bonds are observed for conformers close to transition state. 相似文献
77.
Malace SP Paolone M Strauch S Albayrak I Arrington J Berman BL Brash EJ Briscoe B Camsonne A Chen JP Christy ME Chudakov E Cisbani E Craver B Cusanno F Ent R Garibaldi F Gilman R Glamazdin O Glister J Higinbotham DW Hyde-Wright CE Ilieva Y de Jager CW Jiang X Jones MK Keppel CE Khrosinkova E Kuchina E Kumbartzki G Lee B Lindgren R Margaziotis DJ Meekins D Michaels R Park K Pentchev L Perdrisat CF Piasetzky E Punjabi VA Puckett AJ Qian X Qiang Y Ransome RD Saha A Sarty AJ Schulte E Solvignon P 《Physical review letters》2011,106(5):052501
We measured with unprecedented precision the induced polarization P(y) in (4)He(e,e'p)(3)H at Q(2)=0.8 and 1.3 (GeV/c)(2). The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are overestimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin-independent charge-exchange term in the latter calculation. 相似文献
78.
Albayrak R Albayram S Port J Değirmenci B Acar M Yücel A 《Magnetic resonance imaging》2004,22(7):1047-1051
79.
A. Erdinç O. Canko E. Albayrak 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(4):521-529
The complete phase diagrams of the antiferromagnetic spin-2
Blume-Capel Ising system is studied on the Bethe lattice by the use
of exact recursion relations. In order to specify the states of the
system, i.e. the different spin configurations, the ground state
phase diagram is obtained on the (H/|J|, D/|J|) plane
corresponding to the reduced external magnetic and crystal fields,
respectively. As a result, the thermal change of the
order-parameters, the magnetisations belonging to the two sublattice
system, was investigated to obtain the full phase diagrams of the
system on the (H/|J|, kT/|J|) planes. The behavior of the
order-parameters with respect to the external magnetic field was
also studied for the given values of D/|J|. Besides the
interesting thermal and external magnetic field change of the
sublattice magnetisations, the system also exhibits interesting
critical behaviors including first- and second-order phase
transitions, therefore, triciritical points and the reentrant
behavior. The calculations are carried out for the coordination
number q=4, corresponding to the square lattice, only. 相似文献
80.
Gorkem Sahin Aylin Ziylan Albayrak Zeynep Sarayli Duygu Avci 《Journal of polymer science. Part A, Polymer chemistry》2006,44(23):6775-6781
Novel aromatic mono‐ and diphosphonate monomers based on t‐butyl α‐bromomethacrylate were prepared for use in dental composites. The synthesis of the two monomers involved three steps: the reaction of diethyl phosphite with phenol or hydroquinone, the rearrangement of the resulting phosphate derivatives into o‐hydroxyaryl phosphonates with lithium diisopropylamide, and the reaction of o‐hydroxyaryl phosphonates with t‐butyl α‐bromomethacrylate. Then, the selective hydrolysis of the t‐butyl ester groups of the monomers with trifluoroacetic acid gave the other carboxylic acid containing monomers. The photopolymerization behaviors of the synthesized monomers with glycerol dimethacrylate and triethylene glycol dimethacrylate were investigated with photodifferential scanning calorimetry at 40 °C with 2,2′‐dimethoxy‐2‐phenyl acetophenone as the photoinitiator. The hydrolysis of the t‐butyl groups of the monomers increased the reactivity and the rates of polymerization of the monomers. The mixtures of the acid monomers showed rates of polymerizations similar to those of homopolymerizations of triethylene glycol dimethacrylate and glycerol dimethacrylate. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6775–6781, 2006 相似文献