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11.
M. Veber K.N.V. Duong F. Gaudemer A. Gaudemer 《Journal of organometallic chemistry》1979,177(1):231-237
Allylcobaloximes react under very mild conditions with ethyl bromomalonate to yield allyl-substituted ethylmalonates in good yield. In the case of crotyl-, 3,3 dimethyl, allyl- and cinnamyl-cobaloximes, the substitution occurs with total rearrangement of the allyl groups. Similar rearrangements are observed during the reactions of propargyl- and allenylcobaloximes with BrCH(CO2Et)2 yielding allenyl- and propargyl-malonic esters respectively. 相似文献
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13.
Frost RL Duong L Weier M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(8-9):1853-1859
A series of tungstate bearing minerals including scheelite, stolzite, ferberite, hübnerite, wolframite, russellite, tungstenian wulfenite and cuprotungstite have been analyzed by Raman microscopy. The results of the Raman spectroscopic analysis are compared with published data. These minerals are closely related and often have related paragenesis. Raman microscopy enables the selection of individual crystals of these minerals for spectroscopic analysis even though several of the minerals can be found in the same matrix because of the pargenetic relationships between the minerals. The Raman spectra are assigned according to factor group analysis and related to the structure of the minerals. These minerals have characteristically different Raman spectra. The nu1(Ag) band is observed at 909 cm(-1) and although the corresponding nu1(Bu) vibration should be inactive a minor band is observed around 894 cm(-1). The bands at 790 and 881 cm(-1) are associated with the antisymmetric and symmetric Ag modes of terminal WO2. The band at 695 cm(-1) is interpreted as an antisymmetric bridging mode associated with the tungstate chain. The nu4(Eg) band was absent for scheelite. The bands at 353 and 401 cm(-1) are assigned as either deformation modes or as r(Bg) and delta(Ag) modes of terminal WO2. The band at 462 cm(-1) has an equivalent band in the infrared at 455 cm(-1) assigned as delta(as)(Au) of the (W2O4)n chain. The band at 508 cm(-1) is assigned as nu(sym)(Bg) of the (W2O4)n chain. 相似文献
14.
Larvicidal and structural studies of some triphenyl- and tricyclohexyltin para-substituted benzoates
Quyen Duong Edlira Mitrojorgji George Eng 《Journal of organometallic chemistry》2006,691(8):1775-1779
Several new triphenyl- and tricyclohexyltin para-substituted benzoates were synthesized. Their structures were characterized by IR and Mössbauer spectroscopies. The structures were determined to be four-coordinated monomers. Larvicidal activities of the new compounds as well as other benzoates were evaluated against the 2nd larval instar of the Anopheles stephensi and Aedes aegypti mosquitoes. Results from the screening studies indicated that the triphenyltin benzoates were more toxic towards the Ae. aegypti larvae. A quantitative-structure activity relationship was also developed for the An. stephensi larvae. 相似文献
15.
Hung A. Duong 《Tetrahedron》2006,62(32):7552-7559
A Ni/N-heterocyclic carbene catalyzed cycloaddition of one alkyne and two isocyanates that affords pyrimidine-dione is described. The key to the success of this protocol is the use of unsymmetrically substituted alkynes that favors the formation of pyrimidine-diones over pyridones. A variety of pyrimidine-diones were prepared. A one-pot cycloaddition and Stille coupling were reported for tributyl(1-propynyl)tin. Competition studies also provide insights into the mechanism of the cycloaddition. 相似文献
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17.
Jennifer T. Duong Mark J. Bailey Teresa E. Pick Patrick M. McBride Evelyn L. Rosen Raffaella Buonsanti Delia J. Milliron Brett A. Helms 《Journal of polymer science. Part A, Polymer chemistry》2012,50(18):3719-3727
Water‐dispersible, polymer‐wrapped nanocrystals are highly sought after for use in biology and chemistry, from nanomedicine to catalysis. The hydrophobicity of their native ligand shell, however, is a significant barrier to their aqueous transfer as single particles. Ligand exchange with hydrophilic small molecules or, alternatively, wrapping over native ligands with amphiphilic polymers is widely employed for aqueous transfer; however, purification can be quite cumbersome. We report here a general two‐step method whereby reactive stripping of native ligands is first carried out using trialkyloxonium salts to reveal a bare nanocrystal surface. This is followed by chemically directed immobilization of a hydrophilic polymer coating. Polyacrylic acids, with side‐chain grafts or functional end groups, were found to be extremely versatile in this regard. The resulting polymer‐wrapped nanocrystal dispersions retained much of the compact size of their bare nanocrystal precursors, highlighting the unique role of monomer side‐chain functionality to serve as effective, conformal ligation motifs. As such, they are well poised for applications where tailored chemical functionality at the nanocrystal's periphery or improved access to their surfaces is desirable. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
18.
Xuan Thinh Duong Irina Holmes Ji Li Brett D. Wick Dongyong Yang 《Journal of Functional Analysis》2019,276(4):1007-1060
In this paper we establish the characterization of the weighted BMO via two weight commutators in the settings of the Neumann Laplacian on the upper half space and the reflection Neumann Laplacian on with respect to the weights associated to and respectively. This in turn yields a weak factorization for the corresponding weighted Hardy spaces, where in particular, the weighted class associated to is strictly larger than the Muckenhoupt weighted class and contains non-doubling weights. In our study, we also make contributions to the classical Muckenhoupt–Wheeden weighted Hardy space (BMO space respectively) by showing that it can be characterized via the area function (Carleson measure respectively) involving the semigroup generated by the Laplacian on and that the duality of these weighted Hardy and BMO spaces holds for Muckenhoupt weights with while the previously known related results cover only . We also point out that this two weight commutator theorem might not be true in the setting of general operators L, and in particular we show that it is not true when L is the Dirichlet Laplacian on . 相似文献
19.
Alexander Tuan-Huy Duong Bryan J. Simmons Mohammad Parvez Alam Jesus Campagna Neil K. Garg Varghese John 《Tetrahedron letters》2019,60(3):322-326
This study describes our development of a microfluidic reaction scheme for the synthesis of fused indoline ring systems found in several bioactive compounds. We have utilized a continuous-flow microfluidic reactor for the reaction of hydrazines with latent aldehydes through the interrupted Fischer indolization reaction to form fused indoline and azaindoline products. We have identified optimal conditions and evaluated the scope of this microfluidic reaction using various hydrazine and latent aldehyde surrogates. This green chemistry approach can be of general utility to rapidly produce indoline scaffolds and intermediates in a continuous manner. 相似文献
20.
A dynamic mathematical model is developed for production of Cerenol polyether from 1,3‐propanediol in a batch reactor system. The model accounts for polycondensation reactions and side reactions in the liquid phase and for mass transfer of volatile species to the vapor. Parameters are estimated using measured liquid‐phase concentrations of monomer, oligomers, water, and end groups as well as the mass and composition of condensate collected from the overhead condenser system. The proposed model uses novel probability factors to keep the model equations relatively simple while accounting for the complex influence of superacid catalyst on reaction rates. The model is a significant advance over previous Cerenol models because it better accounts for mass‐transfer rates and for the dynamic behavior of the condenser. In addition, the proposed model accounts for the inhibitory influence of water on polycondensation kinetics due to hydration of hydroxyl ends. The model equations and parameter estimates provide a substantial improvement in fit to the data, especially for long reaction times and high catalyst levels, resulting in a 97% reduction in the value of the weighted least squared objective function compared to equations and parameters from a previous model. 相似文献