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111.
Zayed MA Mohamed GG Abdullah SA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(3):1027-1036
Four novel azo compounds were synthesized; o-phenylazo- (C(14)H(13)N(3)O(2)) (I), p-bromo-o-phenylazo- (C(14)H(13)BrN(3)O(2)) (II), p-methoxy-o-phenaylazo- (C(15)H(16)N(3)O(3)) (III) and p-nitro-o-phenylazo-p-acetamidophenol (C(14)H(13)N(4)O(4)) (IV). These compounds were carefully investigated using elemental analyses, UV-vis, FT-IR, (1)H NMR and mass spectra. Also, the effects of p-substituents such as bromo, methoxy and nitro groups on the mass fragmentation pathways of these dyes were studied using Hammet's effects. This research aimed chiefly to threw lights on the structures-stability relationship of four novel newly prepared azo derivatives of p-acetoamidophenol. The data obtained referred to the variation of mass fragmentation pathways with the variation of p-substituent of these dyes which can be used in industry for various dyeing purposes. This variation is also correlated and verified by molecular orbital calculations which were done on ionic forms of these dyes using semi empirical PM3 program. The biological activities of these dyes were also investigated and its structure relationship was correlated. 相似文献
112.
Mabkhot YN Al-Majid AM Alamary AS Warad I Sedigi Y 《Molecules (Basel, Switzerland)》2011,16(6):5142-5148
Facile and convenient syntheses of bisdimethylthieno[2,3-b]thiophen-2,5-diyl bis(oxazole-2-amine), bis(1H-imidazol-2-amine), bis((3a)-H-indole),[1,2-a]pyrimidine), bis(1H-imidazo[1,2-b][1,2,4]triazole) and bis(9H-benzo[d]imidazo[1,2-a]imidazole) derivatives incorporating a thieno[2,3-b]thiophene moiety from the versatile and readily accessible 1,1'(3,4-dimethylthieno[2,3-b]thiophene-2,5-diyl)-bis(2-bromo-ethanone) (1) are described. 相似文献
113.
Marwan Batiha Mohammednoor Altarawneh Abdullah Alsofi Mohammad Al-Harahsheh Ibrahem Altarawneh Saleh Alrawadieh 《Theoretical chemistry accounts》2011,129(6):823-832
The reaction of aniline with hydrogen atom is investigated herein using the hybrid meta-DFT functional of BB1 K. Hydrogen
atom is found to preferentially add at an ortho position. However, the fate of the o-(C6H5NH2)H adduct is found to be solely the deactivation of the initial addition channel. The rate constant for the abstraction channel
(C6H5NH2 + H → C6H5NH + H2) is fitted by the expression 1.10 × 10−11 exp(−4,200/T) cm3 molecule−1 s−1. Our calculated rate constant for the abstraction channel agrees very well with the available experimental measurements.
Satisfactory agreement is found between calculated and experimental measurements for the displacement channel (C6H5NH2 + H → C6H6 + NH2). Our detailed analysis for the corresponding displacements in toluene and phenol suggests that the three systems exhibit
similar behavior with regard to the relative importance of abstraction and displacement channels. 相似文献
114.
This paper presents a mixed-integer programming formulation to find optimal solutions for the block layout problem with unequal departmental areas arranged in flexible bays. The nonlinear department area constraints are modeled in a continuous plane without using any surrogate constraints. The formulation is extensively tested on problems from the literature. 相似文献
115.
We first investigate the high-temperature behavior of a two-parameter deformed quantum group fermionic gas with GLp,q(2) symmetry, where (p,q)C×C. We then discuss both the structural and thermodynamical differences between GLp,q(2)- and SUr(2)-fermions with r=p/q where (p,q)R×R. 相似文献
116.
The storage of extremely cold (4 K) antiprotons in a Penning trap is an important step toward the creation and study of cold
antihydrogen. The other required ingredient, the largest possible number of comparably cold positrons, is still lacking. These
would be recombined in a high vacuum with the trapped antiprotons, already stored at a pressure below 5×10−17 Torr, thereby avoiding annihilation of the antihydrogen atoms before they can be used in high accuracy measurements or in
controlled collision experiments. In an exploratory experiment, positrons from a 18 mCi22Na source follow fringing field lines of a 6 T superconducting solenoid through tiny apertures in the electrodes of a Penning
trap to strike a tungsten (reflection) moderator. The positron beam is chopped mechanically and a lock-in directly detects
a positron current of 2.5×106e+/s on the moderator. The use of a moderator, unlike an earlier experiment in which < 100 positrons were confined in vacuum,
should greatly increase the number of positrons trapped in high vacuum. 相似文献
117.
1-Acyl-2-alkyl-1,2-dihydropyridines were prepared from 4-trimethylstannylpyridine and Grignard reagents. This methodology was utilized in the synthesis of N-methyl-2-azatricyclo[5.3.1.0]undecane. 相似文献
118.
An injection mode-locked CO2 laser has been used to synchronously pump NH3 and C2D2 mid-infrared lasers resulting in the generation of short (? 1 ns) and powerful (> 1 MW) pulse trains. 相似文献
119.
Awang K Mukhtar MR Hadi AH Litaudon M Latip J Abdullah NR 《Natural product research》2006,20(6):567-572
The alkaloidal extract of the leaves of Phoebe grandis (nees) merr. have provided two new minor alkaloids; phoebegrandine D (1), a proaporphine-tryptamine dimer, and phoebegrandine E (2), an indoloquinolizidine. This is the first report on the occurrence of an indoloquinolizidine in the Phoebe species. The crude extract also exhibited antiplasmodial activity (IC50<8 microg mL-1). The structures of the novel compounds were elucidated by spectroscopic methods, notably 2D NMR and HRMS. 相似文献
120.
K. K. Abdullah K. Karunakaran Nair N. Ramachandran K. M. Varier B. R. S. Babu Antony Joseph Rajive Thomas P. Magudapathy K. G. M. Nair 《Pramana》2010,75(3):459-469
Mass attenuation coefficients (μ/ρ) for Zr, Nb, Mo and Pd elements around their K-edges are measured at 14 energies in the range 15.744–28.564 keV using secondary excitation from thin Zr, Nb, Mo, Rh, Pd,
Cd and Sn foils. The measurements were carried out at the K
α
and K
β
energy values of the target elements by two techniques: (1) Proton-induced X-ray emission (PIXE) and (2) 241Am (300 mCi) source. In PIXE, 2 MeV proton-excited X-rays were detected by a Si(Li) detector. In the second case, X-rays excited
by 59.54 keV photons from the targets were counted by an HPGe detector under a narrow beam good geometry set-up with sufficient
shielding. The results are consistent with theoretical values derived from the XCOM package and indicate that the PIXE data
have better statistical accuracy. 相似文献