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391.
Soraia Meghdadi Mahsa Kiani Farzaneh Fadaei Tirani Maryam Bagheri Kurt Job Schenk 《Journal of Coordination Chemistry》2017,70(14):2409-2424
Two carboxamide ligands, H2bqbenzo {3,4-bis(2-quinolinecarboxamido)benzophenone} and H2bqb {N,N′-bis[(2-quinolinecarboxamide)-1,2-benzene]}, have been prepared using tetrabutylammonium bromide as an environmentally benign reaction medium. Two new Pd(II) complexes, [PdII(bqbenzo)] (1) and [PdII(bqb)] (2), have been synthesized, characterized, and their structures determined by single crystal X-ray diffraction. The di-anionic ligands, bqbenzo2? and bqb2?, are coordinated via two Namide atoms and the nitrogens of the two quinoline rings, with Pd?Namide < Pd–Nquinoline bond lengths. The geometry around palladium(II) in both complexes is distorted square planar. The electrochemical behaviors of the ligands and their Pd(II) complexes have been investigated by cyclic voltammetry in DMF. An irreversible PdII/I reduction is observed at ?1.06 V for 1 and at ?1.177 V for 2, indicating the influence of the R substituent on the central phenyl ring of carboxamide ligands on the PdII/I reduction potential. The ligands and palladium complexes were also screened for in vitro antibacterial activity. The Pd(II) complexes show strong biological activity against S.typhi and E.coli as Gram ?ve and B.cereus and S.aureus as Gram +ve bacteria comparable to the antibiotic penicillin. The antibacterial results also reveal that coordination of Pd(II) significantly improves the activity. 相似文献
392.
The main objective of the present study was to investigate the synergistic effect of simultaneous use of two reinforcing fillers in rubber compounds based on acrylonitrile-butadiene copolymer (NBR). Silica was used as reinforcing filler in all samples and the loading content was 25 phr. 3 and 5 phr of multiwall carbon nanotubes (MWCNT) were used as second reinforcing filler in NBR/silica compounds. Melt mixing method was employed for compound preparation. The effects of carbon nanotube/silica hybrid filler on mechanical and vulcanization characteristics of the rubber compounds were investigated. These results revealed that addition of the reinforcing filler, either carbon nanotube or silica, shortened the optimum cure time (t90) and also scorch time (ts1) of samples compared to that of pure NBR compound. In hybrid compounds, the reduction in optimum cure time and scorch time was higher than that of for silica-filled NBR or CNT-filled NBR compounds. This can be attributed to the synergistic effect between CNT and silica as two reinforcing agents in NBR compounds. Regardless the composition of the reinforcing filler, an increase of the relaxed storage modulus is observed, while the tan δ value is decreased steadily. The dynamic modulus reinforcement of nanocomposites was examined by the Guth Gold and Modified Guth Gold equations. For hybrid samples, the experimental values show a significant positive deviation from model predictions. According to the Barlow’s formula, hybrid compounds show higher burst strength compared to silica or CNT filled NBR compounds. 相似文献
393.
Karimian Somaye Ranjbar Sara Dadfar Mahsa Khoshneviszadeh Mahsima Gholampour Maryam Sakhteman Amirhossein Khoshneviszadeh Mehdi 《Molecular diversity》2021,25(4):2339-2349
Molecular Diversity - A series of ethyl 2-amino-4H-benzo[h]chromene-3-carboxylate derivatives, having phenyl ring with diverse substituents at C4 position of 4H-benzochromene nucleus, were... 相似文献
394.
Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect. 相似文献
395.
Jahan-Bakhsh Raoof Reza Ojani Mahsa Majidian Fereshteh Chekin 《Russian Journal of Electrochemistry》2010,46(12):1395-1401
The electrooxidation of D-penicillamine (D-PA) has been studied in the presence of potassium iodide in various buffered aqueous solutions (4.00 ≤ pH ≤ 9.00) at the
surface of glassy carbon electrode using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. It has
been found that under optimum pH (pH 5.00) in cyclic voltammetry, the electrooxidation of D-PA in the presence of potassium iodide as a homogeneous mediator occurred at a potential about 220 mV less positive than
that in absence of potassium iodide at the surface of glassy carbon electrode. The homogeneous electrocatalytic oxidation
current wave of D-penicillamine was linearly dependent on the D-PA concentration and a linear calibration curve was obtained in the ranges 3.0 × 10−5−1.5 × 10−3 M and 9.0 × 10−6−1.2 × 10−4 M of D-PA with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, respectively. The detection limits (2σ)
were determined as 3.0 × 10−5 and 3.5 × 10−6 M with CV and DPV, respectively. This method was also used for voltammetric determination of D-PA in pharmaceutical preparation by standard addition method. 相似文献
396.
In this study the Zweifach-Fung effect is investigated in a Y-shaped bifurcation when the clearance between the rigid spherical particle and the walls is small ... 相似文献
397.
Fakhari AR Salehi P Heydari R Ebrahimi SN Haddad PR 《Journal of chromatography. A》2005,1098(1-2):14-18
A new method involving concurrent headspace solvent microextraction combined with continuous hydrodistillation (HD-HSME) for the extraction and pre-concentration of the essential oil of Lavandula angustifolia Mill. into a microdrop is developed. A microdrop of n-hexadecane containing n-heptadecane (as internal standard) extruded from the needle tip of a gas chromatographic syringe was inserted into the headspace above the plant sample. After extraction for an optimized time, the microdrop was retracted into the syringe and injected directly into a GC injection port. The effects of the type of extracting solvent, sample mass, microdrop volume and extraction time on HD-HSME efficiency were investigated and optimized. Using this method, thirty-six compounds were extracted and identified. Linalool (32.8%), linalyl acetate (17.6%), lavandulyl acetate (15.9%), alpha-terpineol (6.7%) and geranyl acetate (5.0%) were found to be the major constituents. To the best of our knowledge this is the first report on the use of continuous headspace solvent microextraction coupled with hydrodistillation for investigation of essential oil components. 相似文献
398.
In this article a novel terahertz photodetector based on coherent population trapping (CPT) and in quantum well cascade format is introduced and supplementary simulations and discussions are presented to fulfill the proposed idea. In this scheme, the interference of a short-wavelength probe signal and the terahertz (THz) signals modifies the absorption coefficient of the active region and thus, detection of the short wavelength probe is translated as detection of the THz signal. A ladder structure coupled to the active region extracts the probe-excited carriers and transports them to consequent period via phonon-mediated transport just like conventional quantum cascade structures. 相似文献
399.
400.
Andreas Mayr Muthialu Srisailas Qun Zhao Yuan Gao Heidi Hsieh Mahsa Hoshmand-Kochi Natalie St. Fleur 《Tetrahedron》2007,63(34):8206-8217
Oligo(phenyleneethynylene)s that are of variable length, contain a central arenediimide unit, either a pyromellitdiimide or a naphthalenediimide group, and are terminated by isocyanide groups have been prepared. The extended frameworks were assembled from appropriately functionalized arenediimide and areneformamide units whose lengths were adjusted by adding phenyleneethynylene units. Final transformation of the formamide groups into isocyanide groups gave the title compounds. Several isocyanide-terminated oligo(phenyleneethynylene)s without an arenediimide unit have also been prepared. 相似文献