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The adducts of dimethylformamide, diethylformamide, dimethylacetamide and diethylacetamide with PdCl2 and PtCl2 have been prepared and the IR. spectra of the compounds in nujol mull or in CH2Cl · CH2Cl solution are studied. The lowering of the carbonyl frequency (amide I) shows that the metal is linked by a dative bond to the amide oxygen atom acting as a donor; the lowering is about 33 to 59 cm?1. The decrease of the frequency of the carbonyl group vibration, observed in these cases as for other addition compounds of Lewis acids, is due to an intramolecular electronic displacement in the direction of the amid oxygen atom. 相似文献
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Gioria Esteban Signorini Chiara Taleb María C. Thomas Arne Mihályi Magdolna R. Gutierrez Laura 《Cellulose (London, England)》2021,28(14):9135-9147
Cellulose - Palladium was incorporated into carboxymethylated cellulose fibers as a support, thereby becoming an efficient and stable catalyst for low temperature gas phase reaction. Thus, NO was... 相似文献
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J.R. Meneghini B.S. Carmo S.P. Tsiloufas R.S. Gioria J.A.P. Aranha 《Journal of Fluids and Structures》2011,27(5-6):694-701
Some recent results regarding the global dynamical behaviour of the wake of circular cylinders and airfoils with massive separation are reviewed in this paper. In order to investigate the effect of interference, the three-dimensional instability modes are analysed for the flow around two circular cylinders in tandem. In the same way, the flow around a stalled airfoil is investigated in order to provide a better understanding of the three-dimensional characteristics of wakes forming downstream of a lifting body with massive separation. These results are compared with those found for an isolated cylinder. Some fundamental differences among these flows are discussed. 相似文献
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Estefanía Gioria Dr. Juan del Pozo Dr. Jesús M. Martínez‐Ilarduya Prof. Dr. Pablo Espinet 《Angewandte Chemie (International ed. in English)》2016,55(42):13276-13280
A Pd complex, cis‐[Pd(C6F5)2(THF)2] ( 1 ), is proposed as a useful touchstone for direct and simple experimental measurement of the relative ability of ancillary ligands to induce C?C coupling. Interestingly, 1 is also a good alternative to other precatalysts used to produce Pd0L. Complex 1 ranks the coupling ability of some popular ligands in the order PtBu3>o‐TolPEWO‐F≈tBuXPhos>P(C6F5)3≈PhPEWO‐F>P(o‐Tol)3≈THF≈tBuBrettPhos?Xantphos≈PhPEWO‐H?PPh3 according to their initial coupling rates, whereas their efficiency, depending on competitive hydrolysis, is ranked tBuXPhos≈PtBu3≈o‐TolPEWO‐F>PhPEWO‐F>P(C6F5)3?tBuBrettPhos>THF≈P(o‐Tol)3>Xantphos>PhPEWO‐H?PPh3. This “meter” also detects some other possible virtues or complications of ligands such as tBuXPhos or tBuBrettPhos. 相似文献
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R.S. Gioria J.R. Meneghini J.A.P. Aranha I.C. Barbeiro B.S. Carmo 《Journal of Fluids and Structures》2011,27(5-6):792-797
We assess the effect of the choice of spanwise periodic length on simulations of the flow around a fixed circular cylinder. The Reynolds number is set to 400 because, at this value, both lift coefficient and shedding frequency show significant drop due to three-dimensional flow structures. From the analysis of the three-dimensionalities of the wake and of the integral quantities such as Strouhal number, RMS of lift coefficient and energy contained in the three-dimensional portion of the flow we obtain an estimate of the minimum spanwise length to satisfactorily represent the flow. Furthermore, we observe a distinct wake behavior when the spanwise length is approximately the mode B instability wavelength. 相似文献
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Estefanía Gioria Juan delPozo Jesús M. Martínez‐Ilarduya Pablo Espinet 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(42):13470-13474
A Pd complex, cis‐[Pd(C6F5)2(THF)2] ( 1 ), is proposed as a useful touchstone for direct and simple experimental measurement of the relative ability of ancillary ligands to induce C−C coupling. Interestingly, 1 is also a good alternative to other precatalysts used to produce Pd0L. Complex 1 ranks the coupling ability of some popular ligands in the order PtBu3>o‐TolPEWO‐F≈tBuXPhos>P(C6F5)3≈PhPEWO‐F>P(o‐Tol)3≈THF≈tBuBrettPhos≫Xantphos≈PhPEWO‐H≫PPh3 according to their initial coupling rates, whereas their efficiency, depending on competitive hydrolysis, is ranked tBuXPhos≈PtBu3≈o‐TolPEWO‐F>PhPEWO‐F>P(C6F5)3≫tBuBrettPhos>THF≈P(o‐Tol)3>Xantphos>PhPEWO‐H≫PPh3. This “meter” also detects some other possible virtues or complications of ligands such as tBuXPhos or tBuBrettPhos. 相似文献
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