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排序方式: 共有521条查询结果,搜索用时 31 毫秒
1.
Dr. Ashok Yadav Meghamala Sarkar Dr. Sappati Subrahmanyam Atul Chaudhary Prof. Dr. Evamarie Hey-Hawkins Prof. Dr. Ramamoorthy Boomishankar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(19):4209-4213
The design of porous materials for the recognition of multiple hydrocarbons is highly desirable for the energy-efficient separation and recognition of chemical feedstock. Herein, three new iso-structural porous discrete metal–organic cages of formula {[Pd3(NiPr)3PO]4(R-AN)6} (R-AN=anilate linkers) for the selective recognition of substituted aromatic hydrocarbons are reported. The tetrahedral cages 1 , 2 , and 3 containing anilate, chloranilate, and bromanilate linkers exhibited selective encapsulation of mesitylene, o-xylene, and p-xylene, respectively, over other analogous aromatic hydrocarbons. These selective encapsulations were driven by the variations in the portal diameters present at each of these cages and their interactions with the hydrocarbon guests. These observations are supported by mass spectrometry, NMR studies, and theoretical binding-energy calculations. 相似文献
2.
M. Sharma K. Chaudhary M. Kumari P. Yadav K. Sachdev V. Chandra Janu R. Gupta 《Materials Today Chemistry》2020
A green and environment-friendly magnetically separable nanocomposite, glutathione@magnetite was fabricated sonochemically through the functionalization of Fe3O4 by glutathione which was well characterized using Fourier-transform infrared spectroscopy, ultravoilet-visible spectroscopy, scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermogravimetric analysis, vibrating sample magnetometer, Brunauer-Emmett-Teller, and high-resolution transmission electron microscope. The parameters affecting adsorption including pH, temperature, contact time, initial adsorbate concentration, and adsorbent amount were optimized by batch experiments. The magnetic glutathione@magnetite was applied for the removal of uranium(VI) in water with maximum adsorption capacity found to be 333.33 mg/g in 120 min at a neutral pH at 25 °C showing high efficiency for U(VI) ions. Furthermore, adsorption results obtained from UV-vis spectroscopy were validated by inductively coupled plasma optical emission spectroscopy. The thermodynamic parameters, viz Gibbs free energy (ΔGº), standard enthalpy change (ΔHº), and standard entropy change (ΔSº) of the process were calculated using the Langmuir constants. The pseudo-second-order kinetics model is seen to be applicable for describing the uptake process using a kinetics test. Moreover, desorption studies reveals that glutathione@magnetite can be used repeatedly, and removal efficiency shows only a small decrease after six cycles. Thus, glutathione@magnetite acts as a potential adsorbent for the removal of U(VI) from the water with great adsorption performance. 相似文献
3.
Abhishek Maurya Arun Kumar Mahato Nikita Chaudhary Neha Kesharwani Payal Kachhap Vivek Kumar Mishra Chanchal Haldar 《应用有机金属化学》2020,34(4):e5508
Two vanadium (IV) complexes [VIVO(Haeae-sal)(MeOH)]+ ( 1 ) and [VIVO(Haeae-hyap)(MeOH)]+ ( 2 ) were prepared by reacting [VO(acac)2] with ligands [H2aeae-sal] ( I ) and [H2aeae-hyap] ( II ) respectively. Condensation of 2-(2-aminoethylamino)ethanol with salicylaldehyde and 2-hydroxyacetophenone produces the ligands ( I ) and ( II ) respectively. Both vanadium complexes 1 and 2 are sensitive towards aerial oxygen in solution and rapidly convert into vanadium(V) dioxido species. Vanadium(V) dioxido species crystalizes as the dimeric form in the solid-state. Single-crystal XRD analysis suggests octahedral geometry around each vanadium center in the solid-state. To access the benefits of heterogeneous catalysis, vanadium(V) dioxido complexes were anchored into the polymeric chain of chloromethylated polystyrene. All the synthesized neat and supported vanadium complexes have been studied by a number of techniques to confirm their structural and functional properties. Bromoperoxidase activity of the synthesized vanadium(V) dioxido complexes 3 and 4 was examined by carrying out oxidative bromination of salicylaldehyde and oxidation of thioanisole. In the presence of hydrogen peroxide, 3 shows 94.4% conversion ( TOF value of 2.739 × 102 h−1) and 4 exhibits 79.0% conversion (TOF value of 2.403 × 102 h−1) for the oxidative bromination of salicylaldehyde where 5-bromosalicylaldehyde appears as the major product. Catalysts 3 and 4 also efficiently catalyze the oxidation of thioanisole in the presence of hydrogen peroxide where sulfoxide is observed as the major product. Covalent attachment of neat catalysts 3 and 4 into the polymer chain enhances substrate conversion (%) and their catalytic efficiency increases many folds, both in the oxidative bromination and oxidation of thioether. Polymer supported catalysts 5 displayed 98.8% conversion with a TOF value of 1.127 × 104 h−1 whereas catalyst 6 showed 95.7% conversion with a TOF value of 4.675 × 103 h−1 for the oxidative bromination of salicylaldehyde. These TOF values are the highest among the supported vanadium catalysts available in the literature for the oxidative bromination of salicylaldehyde. 相似文献
4.
5.
Zusammenfassung Die Strömung zäher nicht-newtonscher Flüssigkeiten durch gewellte kreisförmige Rohre unter Wirkung eines axialen Druckgefälles wurde theoretisch und experimentell untersucht. Das besondere Interesse galt dabei der durch die Wellung veränderten Druck-Durchsatz-Charakteristik. Die theoretischen Betrachtungen beziehen sich auf den Grenzfall hinreichend langer Wellen, wo sich der Querschnitt des Flüssigkeitsfadens in Strömungsrichtung nur langsam ändert und sowohl die Trägheit als auch die Elastizität der Flüssigkeit eine untergeordnete Rolle spielen. In dieser Näherung konnte der Durchsatz in Abhängigkeit vom Druckgefälle und den nichtlinearen Fließeigenschaften der Flüssigkeit für beliebige Wellenamplituden analytisch bestimmt werden. Die theoretischen Ergebnisse sind in Einklang mit experimentellen Befunden.
The flow of a non-Newtonian fluid driven by an axial pressure gradient through a corrugated pipe of circular cross-section is analysed theoretically and realized experimentally. Particular attention is directed toward the pressure-discharge characteristics of the pipe which change due to the corrugation. A theory is developed for the limiting case of corrugations with long wave-length, where the cross-section of the pipe varies gradually in the flow direction and the effects of inertia and elasticity of the fluid are of minor importance. Within such a long-wave approximation the flow rate, in dependence on the applied pressure drop and on the non-linear viscous properties of the fluid, is determined analytically for arbitrary wave amplitudes. The theoretical results are in agreement with experimental findings.
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6.
Sudhakar D. G. S. Rao A. Srinivasa Reddy Ch. Venkata Ramana 《Russian Journal of General Chemistry》2019,89(8):1696-1701
Russian Journal of General Chemistry - A series of novel 1,2,4-thiadiazole derivatives bearing 1,2,4-oxadiazole is synthesized. Structures of the synthesized compounds are confirmed by 1H and 13C... 相似文献
7.
Sachin B. Pandya Urmila H. Patel Kaushik P. Chaudhary Bhavesh N. Socha Nikita J. Patel Bhupesh S. Bhatt 《应用有机金属化学》2019,33(12)
Novel cobalt complex of 4‐amino‐N‐(6‐chloropyridazin‐3‐yl)benzene sulfonamide (sulfachloropyridazine) has been synthesized and characterized by elemental analysis, FT‐IR spectroscopy and magnetic susceptibility (VSM). Cobalt complex of Sulfachloropyridazine (Co‐SCP) crystallized in monoclinic space group P21/n with Z = 4. The structure is solved by direct method and refined to R = 0.099 for 4720 reflections with I ?4σ(I). The results of FT‐IR spectra suggest the binding of cobalt atom to the sulfonamide ligand which is in agreement with the crystal structure determination. In crystal structure, molecule is linked via, C‐H … π, C‐Cl … π and π … π intermolecular interactions. The computational studies like the optimization energy and root means square deviation compare with single crystal structure, frontier molecular orbital (Homo‐Lumo energy) and binding energy of the Co‐SCP has been carried out using DFT/B3LYP level of theory in gaseous phase. Hirshfeld surfaces and the 2D‐fingerprint analysis are performed to study the nature of interactions and their measurable contributions towards crystal packing. The interaction of the complex with DNA is investigated using viscosity measurement and absorption titration studies. The result shows the complex bind to DNA with intercalative mode with high DNA‐binding constant (Kb). Also, in vivo and in vitro cytotoxic studies are performed using S. pombe cells and brine shrimp lethality bioassay. DNA‐cleavage study shows better cleaving ability of the complex. 相似文献
8.
Biswanath Das Yallamalla Srinivas Chithaluri Sudhakar Parigi Raghavendar Reddy 《Helvetica chimica acta》2011,94(7):1290-1295
The stereoselective synthesis of the naturally occurring dihydropyranone rugulactone has been accomplished starting from 3‐phenylpropan‐1‐ol employing Maruoka allylation and ring‐closing metathesis as the key steps. 相似文献
9.
Sadiq‐ur‐Rehman Bilal Ahmad Khan Muhammad Aziz Chaudhary Khawaja Ansar Yasin Saqib Ali 《Heteroatom Chemistry》2015,26(6):417-425
Di‐ and triorganotin(IV) carboxylates, RnSn(OCOC(R2)=CHR1)4–n (n = 2 and 3; R = Me, Et, n‐Bu, Ph; R1 = 3‐CH3O‐4‐OHC6H3, R2 = C6H5) were prepared by reacting the corresponding organotin(IV) chloride with the silver salt of the (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐phenylpropenoic acid. The title compounds were investigated and characterized by elemental analysis, infrared (FT‐IR), multinuclear (1H, 13C, 119Sn) NMR, and mass spectrometry, and possible structures were proposed. The complexes and ligand acid ( HL ) have been evaluated in vitro against various bacteria and fungi. The results noticed during the biocidal activity screenings proved their in vitro biological potential. They were also tested for cytotoxicity. 相似文献
10.
Bharat Indu Chaudhary Jeffrey M. Cogen J. Scott Parent 《Journal of Thermal Analysis and Calorimetry》2011,105(1):279-285
Organic solids have been prepared from radical-initiated activation of solutions composed of tetradecane and triallyl trimesate
(TAM) monomer or triallyl phosphate (TAP) monomer using a recently developed variation of precipitation polymerization methods.
The powders, which comprise fused aggregates, are shown to be rich in monomer (83–88 wt% TAM or 86–92 wt% TAP), and are believed
to be formed by a combination of hydrocarbon addition and allyl group oligomerization. TAM-g-tetradecane primary particles are on the order of 500 nm in diameter, while TAP-g-tetradecane particles are on the order of 100–200 nm diameter. These products are thermochemically assessed using a combination
of differential scanning calorimetry, thermogravimetry and pyrolysis combustion flow calorimetry. The phosphorus-containing
TAP-g-tetradecane shows exothermic activity around 230 °C, likely due to thermal decomposition of the trialkyl phosphate moiety,
and may find use in advanced materials applications. 相似文献