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1.
Tarek M. El-Gogary Mostafa A. Diab Shreen F. El-Tantawy 《Monatshefte für Chemie / Chemical Monthly》2006,137(8):1027-1042
Summary. Equilibrium constants and molar extinction coefficients for 1:1 charge-transfer complexes between 2-hydroxyaniline (HA), 5-chloro-2-hydroxyaniline (CHA), and 4-bromo-2,6-dimethylaniline (BMA) as donors and iodine, as a typical σ-acceptor were determined spectrophotometrically in chloroform, dichloromethane, and
carbontetrachloride solutions. Spectral characteristics and formation constants are discussed in terms of donor molecular
structure and solvent polarity. The stoichiometry of the complexes was established to be 1:1. For this purpose, optical data
were subjected to the form of the Rose-Drago equation for 1:1 equilibria. Electronic absorption spectra of the studied anilines were measured in different solvents. Spectral
data were reported and band maxima were assigned to the appropriate molecular orbital transitions (π–π* and n–π* electronic transition). Solvent effects on the electronic transitions were discussed. Optimized geometry of the studied anilines
was obtained at B3LYP/6-31 + G(d). The effect of the electronic factors of the substituents on the geometrical parameters
of the ring has been explored. Geometrical values of the ring deviate from the regular hexagonal ring. Intramolecular H-bonds
in HA and CHA have been computed at B3LYP/6-31 + G(d) and MP2/6-31 + G(d) levels. The H-bonding distance was calculated to be 2.105 ? in
HA and 2.127 ? in CHA.
Abstracted from her M.Sc. thesis 相似文献
2.
Reda A. Haggam Mohamed G. Assy Mohamed H. Sherif Mohamed M. Galahom 《Research on Chemical Intermediates》2017,43(11):6299-6315
1,3-Thiazine 3 was obtained from cinnamoyl thiourea derivative 2 as the kinetic control product. Refluxing of 2 with sodium ethoxide afforded pyrimidine derivative 4. Moreover, stirring of 2 with bromine/acetic acid gave thiazole 5 that was condensed with o-phenylene diamine forming benzimidazole 6. Heating of arylthiourea 8 with maleic anhydride or phenacyl chloride afforded thiazole derivatives 9 and 10, respectively. Condensation of compound 10 with o-phenylene diamine gave benzimidazole 11. Reaction of p-amino benzoic acid with chloro acetyl isothiocyanate, acetylacetone and ethylacetoacetate produced imidazole 14, enaminone 15 and crotonate 16 derivatives, respectively. Stirring a mixture of benzoyl isothiocyanate with 15 and/or 16 resulted in pyridine-2-thione 17. The yields of the prepared compounds were 41–93%. The experimental section is simple and easy. The detailed synthesis, spectroscopic data, IC50 and antitumor activity of the synthesized compounds were reported. The cytotoxicity of the newly synthesized products showed that compound 4 is the most active compound towards the cancer cell line at which its reactivity is higher than that of the standard doxorubicin (anticancer reference drug). 相似文献
3.
Afzal Hafiz Muhammad Shehzad Farrukh Zubair Mukarram Bakather Omer Yahya Al-Harthi Mamdouh A. 《Journal of Thermal Analysis and Calorimetry》2020,139(1):353-365
Journal of Thermal Analysis and Calorimetry - This article discusses the effect of microwave irradiation on the thermal properties of poly(vinyl alcohol)/graphene nanocomposites, prepared using a... 相似文献
4.
El-Wahab AH Al-Fifi ZI Bedair AH Ali FM Halawa AH El-Agrody AM 《Molecules (Basel, Switzerland)》2011,16(1):307-318
Vilsmeier formylation of 2-(1-phenylhydrazonoethyl)naphtho[2,1-b]furan (2) gave 3-naphtho[2,1-b]furan-2-yl-1-phenyl-1H-pyrazole-4-carbaldehyde (3), which was reacted with C- and N-nucleophiles to afford naphthofuranpyrazol derivatives 4-8. Treatment of 2-[(3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene]-malononitrile (4a) with reactants having active hydrogen and Et?N gave the corresponding pyrazoline, pyran and chromene addition product derivatives 10, 12 and 13, consisting of three different connected heterocyclic moieties. Reaction of 1-((3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl) methylene)-2-phenylhydrazone (6b) with AcONa and ethyl bromoacetate or chloroacetone afforded the thiazolidinone and methylthiazole derivatives 14 and 15, respectively. In addition, intramolecular cyclization of 6d with Ac?O afford the corresponding 1,3,4-thiadiazol-2-yl acetamide derivative 16. The structures of the synthesized compounds were confirmed by IR, 1H-NMR/13C-NMR and mass spectral studies. Compound 14 showed promising effects against the tested Gram positive and negative bacteria and fungi. 相似文献
5.
K. F. Hassan S. Spellerberg B. Scholten Z. A. Saleh S. M. Qaim 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):689-694
A novel anion-exchange chromatographic method for separation of radioiodine from an antimony target irradiated with 3He- or α-particles was developed, with separation yield of radioiodine amounting to 90 ± 5 % and its decontamination factor from the Te and Sb radionuclides to ~104. The optimized separation method developed was then applied to the production of 124I via the 121Sb(α,n)124I process using a highly enriched 121Sb target. Quality control tests showed that the separated 124I occurred >99 % as iodide and the longer lived impurities 126I and 125I amounted to 0.16 % and <0.05 %, respectively. The trace level of inactive Sb impurity was determined by ICP–OES. 相似文献
6.
《Experimental Thermal and Fluid Science》2005,29(2):179-187
In order to predict sediment movements in coastal environments, the interaction between these particles and turbulence should be better understood. Although previous studies have particularly shown the importance of the turbulence length scales on sediment transport for current flows, few measurements have been made on wave/current flows. The purpose of our experiments is to get a better knowledge on wave action on these characteristic length scales. For this study, in the context of a grid-generated turbulence, we aimed to describe evolution of turbulence macro and micro scales in two kinds of free surface flow. Indeed, current and wave/current flows are studied. Two data analysis techniques are used to estimate these characteristic length scales depending on flow conditions. Whereas a well-known energetic method is used for current flow, a specific analysis based on correlation measurements is lead to describe temporal evolution of turbulence length scale over the wave period. As a main result, we show that the free surface causes a vortex stretching for current flow and that turbulence length scales follow a periodic evolution with a frequency which is twice as the swell period. The turbulence length scales also depend on wave period and amplitude. 相似文献
7.
Bakr F. Abdel-Wahab Mohamed F. El-Mansy Rizk E. Khidre 《Journal of the Iranian Chemical Society》2013,10(6):1085-1102
Benzoylacetonitriles are easily available and have high chemical reactivity due to the presence of three active moieties; nitrile, carbonyl, and active methylene functions. This review article represents a survey covering the synthetic strategies leading to five six-membered heterocycles; pyrans, pyridazines, pyrimidines, pyrazines, and triazine compounds; utilizing benzoylacetonitriles as starting precursor since 1985. The reactions are subdivided into groups that cover the synthetic methods of these heterocycles. 相似文献
8.
Ajaj Rahaf Shubyar Nasser Alashban Yazeed El-Sayed Samar Salah Tamar Al Yafei Mohammed A. Salem 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):923-928
Journal of Radioanalytical and Nuclear Chemistry - Groundwater is the most valuable resource in arid regions, such as UAE. Estimations of natural radionuclide concentrations are important to... 相似文献
9.
《中国化学快报》2020,31(6):1593-1597
As one of the most environmentally friendly photovoltaic(PV) conversion equipments,aqueousprocessed CdTe nanocrystal solar cells(NC SCs) have attracted great interest in recent years because of their excellent properties such as high charge-carrier mobility and broad absorption.However,two issues including interfacial recombination and leakage current seriously restrict their performance.In this paper,insulating polymer poly(vinyl pyrrolidone)(PVP) is introduced into CdTe NC SCs to solve the problems.The experimental results of transmission electron microscopy(TEM),atomic force micro scopy(AFM) and dark current measurements,etc.,demonstrate the leakage current is effectively suppressed by introducing PVP.Through further designing device structure,the reduction of interfacial recombination after introducing PVP is confirmed.By strategically taking the advantages of PVP properties(e.g.,water solubility and thermostability),the power conversion efficiency of the devices with PVP is enhanced by almost 37% compared to pure CdTe devices.This work demonstrates an effective and low-cost method to fabricate NC SCs via aqueous route.Moreover,it also proves that appropriate content of insulating polymer is of beneficial in promoting the PV performance. 相似文献
10.
Optically stimulated luminescence (OSL) measurements have been carried out on single crystals of Ag doped Li2B4O7 (LTB:Ag) after exposure to various nuclear radiations. The time integrated OSL intensity is found to be linear in the range from 0.1 Gy to 500 Gy. Fading of the OSL signal was found to be around 36% in 48 h. The presence of 6Li and 10B has been gainfully utilized to measure doses of thermal neutrons. Further, the large difference between the wavelength of the stimulation source (∼460 nm) and emission from the LTB:Ag at 270 nm has enhanced the signal-to-noise ratio in a simple OSL set-up with suitable filters. The high sensitivity of the LTB:Ag to thermal neutrons will be useful in variety of applications including personal dosimetry in mixed-fields and imaging devices for neutron radiography. 相似文献