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We find that Magtrieve™ (CrO2) catalyzes the oxidation of a wide variety of alcohols with periodic acid as the terminal oxidant. Mild conditions, short reaction times, and facile aqueous work-up make this a most attractive method. Olefins are not oxidized under these conditions; thus alcohols react selectively in the presence of alkenes. Conditions have been optimized with respect to catalyst loading, solvent, and co-oxidant; and the scope of the reaction includes primary and secondary benzylic, allylic, and aliphatic alcohols. 相似文献
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Daniel A. Ruddy Donald H. Berry Chip Nataro 《Journal of organometallic chemistry》2008,693(1):169-172
New synthetic routes to 1-methyl-1-silaindane (1b) and 1-methyl-1-germaindane (1b) were developed and the desired products were obtained in good isolated yield. Compounds 1a and 1b were fully characterized by mass spectroscopy, 1H and 13C{1H} NMR, and infrared spectroscopy. 相似文献
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Sarah L. Martinak Sarah J. Kolb William R. McNamara James A. Golen Chip Nataro 《Journal of organometallic chemistry》2006,691(17):3627-3632
The oxidative electrochemistry of 1,1′-bis(diphenylphosphino)osmocene (dppo) and 1,1′-bis(diphenylarsino)ferrocene (dpaf) was studied in dichloromethane with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. The [MCl2(P∩P)] (M = Pd or Pt; P∩P = dppo or 1,1′-bis(diphenylphosphinoindenyl)iron) complexes were prepared, studied electrochemically and the X-ray structures of dppo and [PdCl2(dppo)] were determined. 相似文献
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Kyle D. Reichl Chelsea L. Mandell William G. Dougherty Chip Nataro 《Journal of organometallic chemistry》2011,696(24):3882-3894
The electrochemistry of 1,1′-bis(diphenylphosphino)cobaltocenium hexafluorophosphate ([dppc][PF6]), 1,1′-bis(dicyclohexylphosphino)cobaltocenium hexafluorophosphate ([dcpc][PF6]), 1,1′-bis(di-iso-propylphosphino)cobaltocenium hexafluorophosphate ([dippc][PF6]), and 1-(di-tert-butylphosphino)cobaltocenium hexafluorophosphate ([1-dtbpc][PF6]) was examined in methylene chloride with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. A reversible reductive wave followed by an irreversible wave at more negative potentials was observed. Ten new phosphinothioyl ([dppcS2][PF6], [dcpcS2][PF6], [dippcS2][PF6], [1-dtbpcS][PF6], and 1,1′-bis(dicyclohexylphosphinothioyl)ferrocene) and phosphinoselenoyl derivatives ([dppcSe2][PF6], [dcpcSe2][PF6], [dippcSe2][PF6], [1-dtbpcSe][PF6], and 1,1′-bis(dicyclohexylphosphinoselenoyl)ferrocene) were prepared and characterized, and the structures of eight of these compounds were determined. The electrochemistry of these phosphinochalcogenyl cobaltocenium compounds, as well as the previously prepared [dppcO2][PF6], displayed two reversible reductive waves at potentials less negative than that of the free phosphines. A correlation was found to exist between the Hammett substituent constant σp and the reduction potentials of these compounds. In addition, the phosphinoselenoyl [dppcSe2][PF6], [dcpcSe2][PF6], and [dippcSe2][PF6] displayed an electrochemically irreversible oxidative wave, potentially indicating an intramolecular Se-Se bonded trication. The electrochemistry of three new and five previously reported transition metal complexes of the general formula [MnCl2(P∩P)][PF6] (M = Pd or Pt, n = 1, P∩P = dppc, dcpc or dippc; M = Au, n = 2, P∩P = dppc or dcpc)) was also examined displaying at least two reductive waves at potentials less negative than that of the free phosphines. Comparison of the electrochemical data with that previously obtained for analogous ferrocenes indicates that a correlation exists between the reduction potentials of the cobaltocenium phosphines and the potentials at which oxidation of the ferrocene phosphines occurs. In addition, the structure of [Au2Cl2(dppc)][PF6] was determined. 相似文献
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Svetlana I. Evstratova Daniel Antrim Chip Fillingane John A. Pojman 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3601-3608
Isothermal frontal polymerization is a directional polymerization that utilizes the Norish‐Trommsdorff (gel) effect to produce optical gradient materials. When a solution of methyl methacrylate and thermal initiator contacts a polymer seed (a small piece of poly(methyl methacrylate), a viscous region is formed in which the polymerization rate is faster than in the bulk solution. We obtained definitive evidence of the isothermal nature of the process by placing thermocouples above the propagating front. Using the optical technique of laser line deflection (Weiner's method), we studied the front propagation to determine the induction period, and the maximum distance propagated as a function of the molecular weight of the seed. We determined that the polymer seed must have a minimum molecular weight to initiate a front. We also determined that oxygen would act as a bulk polymerization inhibitor and increase the front propagation distance, but after purging the monomer–initiator solution with oxygen for several hours, the distance was shortened. We ascribed this behavior to the formation of peroxy radicals from the slow decomposition of the initiator and subsequent reaction with oxygen. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3601–3608, 2006 相似文献
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M. M. Chip 《Journal of Mathematical Sciences》1998,90(5):2416-2420
We propose studying generalized moment representations of a form in which it suffices to apply a system of orthogonal polynomials
in order to procure the biorthogonality conditions in the construction of superdiagonal Padé polynomials using generalized
moment representations. The algebraic polynomials in the moment representation are to be sought as the linear forms of biorthogonal
polynomials. We obtain the relations between the coefficients of these linear forms and the generalized moments, and we also
establish conditions for the existence and uniqueness of generalized moment representations of polynomial form.
Translated fromMatematichni Metodi ta Fiziko-Mekhanichni Polya, Vol. 39, No. 2, 1996, pp. 110–115. 相似文献
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Direct Carbocyclizations of Benzoic Acids: Catalyst‐Controlled Synthesis of Cyclic Ketones and the Development of Tandem aHH (acyl Heck–Heck) Reactions 下载免费PDF全文
Kelsey C. Miles Chi “Chip” Le Prof. Dr. James P. Stambuli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(36):11336-11339
The formation of exo‐methylene indanones and indenones from simple ortho‐allyl benzoic acid derivatives has been developed. Selective formation of the indanone or indenone products in these reactions is controlled by choice of ancillary ligand. This new process has a low environmental footprint as the products are formed in high yields using low catalyst loadings, while the only stoichiometric chemical waste generated from the reactants in the transformation is acetic acid. The conversion of the active cyclization catalyst into the Hermman–Beller palladacycle was exploited in a one‐pot tandem acyl Heck–Heck (aHH) reaction, and utilized in the synthesis of donepezil. 相似文献
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Tatiana Trejos Robert Koons Stefan Becker Ted Berman JoAnn Buscaglia Marc Duecking Tiffany Eckert-Lumsdon Troy Ernst Christopher Hanlon Alex Heydon Kim Mooney Randall Nelson Kristine Olsson Christopher Palenik Edward Chip Pollock David Rudell Scott Ryland Anamary Tarifa Melissa Valadez Peter Weis Jose Almirall 《Analytical and bioanalytical chemistry》2013,405(16):5393-5409
Elemental analysis of glass was conducted by 16 forensic science laboratories, providing a direct comparison between three analytical methods [micro-x-ray fluorescence spectroscopy (μ-XRF), solution analysis using inductively coupled plasma mass spectrometry (ICP-MS), and laser ablation inductively coupled plasma mass spectrometry]. Interlaboratory studies using glass standard reference materials and other glass samples were designed to (a) evaluate the analytical performance between different laboratories using the same method, (b) evaluate the analytical performance of the different methods, (c) evaluate the capabilities of the methods to correctly associate glass that originated from the same source and to correctly discriminate glass samples that do not share the same source, and (d) standardize the methods of analysis and interpretation of results. Reference materials NIST 612, NIST 1831, FGS 1, and FGS 2 were employed to cross-validate these sensitive techniques and to optimize and standardize the analytical protocols. The resulting figures of merit for the ICP-MS methods include repeatability better than 5 % RSD, reproducibility between laboratories better than 10 % RSD, bias better than 10 %, and limits of detection between 0.03 and 9 μg g?1 for the majority of the elements monitored. The figures of merit for the μ-XRF methods include repeatability better than 11 % RSD, reproducibility between laboratories after normalization of the data better than 16 % RSD, and limits of detection between 5.8 and 7,400 μg g?1. The results from this study also compare the analytical performance of different forensic science laboratories conducting elemental analysis of glass evidence fragments using the three analytical methods. Figure
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