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Victoria A. Ternes Hannah A. Morgan Austin P. Lanquist Michael J. Murray Bradley M. Wile 《应用有机金属化学》2020,34(4):e5459
Herein we report the preparation of a series of Ru(II) complexes featuring α-iminopyridine ligands bearing thioether functionality (NNSR, where R = Me, CH2Ph, Ph). Metallation using [(p-cymene)RuCl]2 permits access to Ru complexes with a κ2-N,N donor set in which the thioether moiety remains uncoordinated. In the presence of a strong field ligand such as acetonitrile or triphenylphosphine, the p-cymene moiety is displaced, and the ligand adopts a κ3-N,N,S binding mode. These complexes are characterized using a combination of solution and solid state methods, including the crystal structure of [(NNSMe)Ru (NCMe)2Cl]Cl. The κ2-N,N-Ru(II) complexes are shown to serve as efficient precatalysts for the oxidation of sec-phenethyl alcohol at modest loadings (alcohol: Ru = 20:1), using a variety of external oxidants and solvents. The complex bearing an S-Ph donor was found to be the most active oxidation catalyst of those surveyed, suggesting that the thioether donor plays an active role in the catalytic cycle. 相似文献
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We study an extension of the classical graph cut problem, wherein we replace the modular (sum of edge weights) cost function by a submodular set function defined over graph edges. Special cases of this problem have appeared in different applications in signal processing, machine learning, and computer vision. In this paper, we connect these applications via the generic formulation of “cooperative graph cuts”, for which we study complexity, algorithms, and connections to polymatroidal network flows. Finally, we compare the proposed algorithms empirically. 相似文献
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Grace C. Thaggard Dr. Gabrielle A. Leith Daniil Sosnin Dr. Corey R. Martin Kyoung Chul Park Margaret K. McBride Dr. Jaewoong Lim Brandon J. Yarbrough Buddhima K. P. Maldeni Kankanamalage Gina R. Wilson Austin R. Hill Dr. Mark D. Smith Prof. Dr. Sophya Garashchuk Prof. Dr. Andrew B. Greytak Prof. Dr. Ivan Aprahamian Prof. Dr. Natalia B. Shustova 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202211776
Confinement-imposed photophysics was probed for novel stimuli-responsive hydrazone-based compounds demonstrating a conceptual difference in their behavior within 2D versus 3D porous matrices for the first time. The challenges associated with photoswitch isomerization arising from host interactions with photochromic compounds in 2D scaffolds could be overcome in 3D materials. Solution-like photoisomerization rate constants were realized for sterically demanding hydrazone derivatives in the solid state through their coordinative immobilization in 3D scaffolds. According to steady-state and time-resolved photophysical measurements and theoretical modeling, this approach provides access to hydrazone-based materials with fast photoisomerization kinetics in the solid state. Fast isomerization of integrated hydrazone derivatives allows for probing and tailoring resonance energy transfer (ET) processes as a function of excitation wavelength, providing a novel pathway for ET modulation. 相似文献
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Sally M. McIntyre Jill Wisnewski Ferguson R.S. Houk 《Spectrochimica Acta Part B: Atomic Spectroscopy》2011,66(8):581-587
The method of comparing experimental and calculated ion ratios to determine a gas kinetic temperature (Tgas) characteristic of the origin of a polyatomic ion in inductively coupled plasma-mass spectrometry (ICP-MS) is applied to ArO+. Repeated measurements of ion ratios involving this species yield erratic Tgas values. Complications arise from the predicted presence of a low-lying excited electronic state (2Π) above the 4Σ ground state. Omission of this excited state yields unreasonably high temperatures (> 10,000 K) for nine out of nineteen trials. Inclusion of the excited electronic state in the partition function of ArO+ causes temperatures to increase further. The problem appears to be related to the prediction that ArO+ in the 2Π excited state dissociates into Ar+ and O, different products than ArO+ 4Σ which dissociates into Ar and O+. Adjustments to the calculations to account for these different products yield reasonable temperatures (2100 to 3500 K) that are consistent from day-to-day and similar to those seen for other weakly-bound polyatomic ions. 相似文献
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Hun Lee Mataz Alcoutlabi Ozan Toprakci Guanjie Xu Jill V. Watson Xiangwu Zhang 《Journal of Solid State Electrochemistry》2014,18(9):2451-2458
Nanofiber-coated membrane separators were prepared by electrospinning polyvinylidene fluoride-co-chlorotrifluoroethylene (PVDF-co-CTFE) nanofibers onto three different microporous membrane substrates. The nanofibers on the membrane substrates showed uniform morphology with average fiber diameters ranging from 129 to 134 nm. Electrolyte uptakes, ionic conductivities, and interfacial resistances were studied by soaking the nanofiber-coated membrane separators with a liquid electrolyte solution of 1 M lithium hexafluorophosphate in ethylene carbonate/dimethylcarbonate/ethylmethyl carbonate (1:1:1 by volume). Compared with uncoated membranes, nanofiber-coated membranes had greater electrolyte uptakes and lower interfacial resistances to the lithium electrode. It was also found that after soaking in the liquid electrolyte solution, nanofiber-coated membranes exhibited higher ionic conductivities than uncoated membranes. In addition, lithium-ion half cells containing nanofiber-coated membranes were evaluated with a LiFePO4 cathode for charge–discharge capacities and cycle performance. The cells containing a nanofiber-coated separator membrane showed high discharge specific capacities and good cycling stability at room temperature. Results demonstrated that coating PVDF-co-CTFE nanofibers onto microporous membrane substrates is a promising approach to obtain new and high-performance separators for rechargeable lithium-ion batteries. 相似文献