共查询到20条相似文献,搜索用时 15 毫秒
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Huitao Liu Yingying Wen Feng Luan Yuan Gao Xiuyong Li 《Central European Journal of Chemistry》2009,7(3):439-445
The half-wave potential (E1/2) is an important electrochemical property of organic compounds. In this work, a quantitative structure-property relationship
(QSPR) analysis has been conducted on the half-wave reduction potential (E1/2) of 40 substituted benzoxazines by means of both a heuristic method (HM) and a non-linear radial basis function neural network
(RBFNN) modeling method. The statistical parameters provided by the HM model (R2 =0.946; F=152.576; RMSCV=0.0141) and the RBFNN model (R2=0.982; F=1034.171 and RMS =0.0209) indicated satisfactory stability and predictive ability. The obtained models showed that
benzoxazines with larger Min valency of a S atom (MVSA), lower Relative number of H atom (RNHA) and Min n-n repulsion for
a C-H bond (MnnRCHB) and Minimal Electrophilic Reactivity Index for a C atom (MERICA) can be more easily reduced. This QSPR
approach can contribute to a better understanding of structural factors of the organic compounds that contribute to the E1/2, and can be useful in predicting the E1/2 of other compounds.
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The reaction mechanism between AlX and HX (X = Br, Cl, and F) have been characterized in detail using DFT as well as the ab initio method. The reaction yielding AlX3 and molecular hydrogen was calculated to be highly exothermic. The present calculations also show that the possible routes
to the trihalides species start more favorable with the primary insertion product AlX2H than with the biadduct AlX(HX)2 one.
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Meysam Soleymani Ahmad Moheb Ezatolah Joudaki 《Central European Journal of Chemistry》2009,7(4):809-817
Single phase nanocrystalline La0.6Ca0.4MnO3 powder was synthesized by both the usual and a modified citrate gel precursor method, and the effects on the formation of
homogeneous nano-sized powder with a perovskite structure were investigated. In the modified method, single phase La0.6Ca0.4MnO3 powder with an average particle size of 17.2 nm was obtained when the powder was pyrolyzed at 520°C for 2 h. Its specific
surface area was 40.7 m2 g−1, about 4-fold larger than that of powder made by the usual citrate gel method.
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Natarajan Thilagavathi Chinnasamy Jayabalakrishnan 《Central European Journal of Chemistry》2010,8(4):842-851
Ru(III) complexes of the type [RuXB(L)2] have been prepared by the reaction of 3,4-dihydropyrimidin-2(1H)-ones/thiones (HL1–HL4) with the precursors of the type [RuX3B3] where X=Cl or Br; B=PPh3 or AsPh3 and L is the deprotonated ligand. The synthesized complexes were characterized by physico-chemical methods, electrochemical
and magnetic moment data. The catalytic efficiency of the complexes were examined in the oxidation of alcohols and antimicrobial
studies were also carried out.
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Azza A. Shoukry Mohamed M. Shoukry Mohamed N. Hafez 《Central European Journal of Chemistry》2010,8(4):797-805
The kinetics of base hydrolysis of glycine, histidine, and methionine methyl esters in the presence of [Pd(pip)(H2O)2]2+ complex, where pip is piperazine, is studied in aqueous solutions, at T = 25°C, and I = 0.1 mol dm−3. The rate of ester hydrolysis for glycine methyl ester is studied at different temperature and dioxane/water solutions of
different compositions. The kinetic data are fit under the assumption that the hydrolysis proceeds in one step. The activation
parameters for the base hydrolysis of the complexes are evaluated
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The triplet excited state properties and photosensitization mechanisms of indigo were investigated based on density functional
theory calculations. The solvent effects on the photosensitization mechanisms of indigo have also been considered. The thermodynamic
feasibility of the possible 1O2 and O2·−-photogeneration pathways by triplet excited state indigo in different solvents was explored, in order to gain some deeper
insights into the photosensitization characters of the dye.
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In the present study, Quantitative Structure-Activity Relationship (QSAR) modeling has been carried out for lipid peroxidation
(LPO)-inhibition potential of a set of 27 flavonoids, using structural and topological parameters. For the development of
models, three methods were used: (1) stepwise regression, (2) factor analysis followed by multiple linear regressions (FA-MLR)
and (3) partial least squares (PLS) analysis. The best equation was obtained from stepwise regression analysis (Q2 = 0.626) considering the leave-oneout prediction statistics.
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Gheorghe Roman 《Central European Journal of Chemistry》2012,10(5):1516-1526
Benzimidazole, benzimidazoles diversely substituted at position 2, and 5,6-dimethylbenzimidazole have been alkylated at N
1 with ketonic Mannich bases derived from acetophenones, acetylnaphthalenes, 2-acetylthiophene and 1-tetralone to afford a
series of novel 1-(3-oxopropyl)benzimidazoles. The reduction of these transamination products with NaBH4 in methanol produced the corresponding 1-(3-hydroxypropyl)benzimidazoles in excellent yields.
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Phase equilibria established in the PbO - BiVO4 system over the whole component concentration range up to 1000°C have been investigated. A phase diagram has been constructed
using DTA and XRD.
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Tsonko Kolev Bojidarka B. Koleva Michael Spiteller 《Central European Journal of Chemistry》2008,6(3):393-399
The applications of linear-polarized IR-spectroscopy to oriented colloid suspensions in a nematic host are demonstrated with
croconic and rhodizonic acids. The experimental IR vibrational assignments of the solid-state of both neutral compounds are
presented. Assignments are supported by theoretical quantum chemical calculations and vibrational analysis at the DFT level
of theoretical approximation with the 6-311++G** basis set.
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Mohamed R. Shehate Mohamed M. Shoukry Mona S. Ragab 《Central European Journal of Chemistry》2012,10(4):1253-1261
The Pd(DMPA)Cl2 complex, where DMPA = N,N-dimethylaminoproylamine, was synthesized and characterized. The stoichiometry and stability constants of the complexes formed between various dicarboxylic acids and [Pd(DMPA)(H2O)2]2+ were investigated. The effect of solvent dielectric constant, chloride ion concentration of the medium and temperature on the stability constant of the cyclobutanedicaroxylic acid (CBDCA) complex was investigated. The equilibrium constants for the displacement of coordinated CBDCA by inosine, taken as an example of DNA constituents, were calculated. The results are expected to contribute to the chemistry of antitumour agents. 相似文献
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Abdülhadi Baykal Yüksel Köseoğlu Mehmet Şenel 《Central European Journal of Chemistry》2007,5(1):169-176
Heating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size
estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements
confirm a typical Mn2+signal with a highly resolved hyperfine structure.
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