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31.
Metal‐Catalyzed “On‐Demand” Production of Carbonyl Sulfide from Carbon Monoxide and Elemental Sulfur
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Wesley S. Farrell Peter Y. Zavalij Prof. Lawrence R. Sita 《Angewandte Chemie (International ed. in English)》2015,54(14):4269-4273
The group 6 molybdenum(II) cyclopentadienyl amidinate (CPAM) bis(carbonyl) complex [Cp*Mo{N(iPr)C(Ph)N(iPr)}(CO)2] (Cp*=η5‐C5Me5) serves as a precatalyst for the high‐yielding photocatalytic production of COS from CO and S8 under near‐ambient conditions (e.g., 10 psi, 25 °C). Further documented is the isolation and structural characterization of several key transition‐metal intermediates which collectively support a novel molybdenum(IV)‐based catalytic cycle as being operative. Finally, in the presence of an excess amount of a primary amine, it is demonstrated that this catalytic system can be successfully used for the “on‐demand” generation and utilization of COS as a chemical reagent for the synthesis of ureas. 相似文献
32.
C. Orofino C. Foucher F. Farrell N. J. Findlay B. Breig A. L. Kanibolotsky B. Guilhabert F. Vilela N. Laurand M. D. Dawson P. J. Skabara 《Journal of polymer science. Part A, Polymer chemistry》2017,55(4):734-746
A series of star-shaped oligofluorene molecules, each containing a TPE core, have been specifically designed and produced to show effective aggregation-induced emission (AIE). Each molecule differs either in the number of fluorene units within the arms (e.g., 1 or 4, compounds 4 and 5 ), or the terminal group positioned at the end of each arm (e.g., H, TMS, or TPA, compounds 4 , 6 , and 7 ). Although they are all poor emitters in solution phase they become efficient yellow-green luminogens in the condensed state. Their AIE properties were investigated in THF/H2O mixtures, with each molecule exhibiting a clear emission enhancement at specific water contents. An all-organic distributed feedback (DFB) laser was fabricated using compound 4 as the gain material and exhibited an average threshold energy fluence of 60 ± 6 μJ/cm2 and emission in the green region. Furthermore, piezofluorochromism studies on a thin film of this material displayed a linear dependence of the amplified spontaneous emission (ASE) peak position on applied pressure, indicating potential applications as lasing-based pressure sensors. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 734–746 相似文献
33.
The effect of spatial wandering on experimental laser velocimeter measurements of the end-wall vortices in an axial-flow pump 总被引:1,自引:0,他引:1
In a high Reynolds number axial-flow pump, laser velocimeter (LV) measurements were made to study the size and structure of the end-wall vortex. The time mean measurements show that the core size of the end-wall vortex increased with decreasing tip clearance, which is contrary to existing theory. Observations of cavitation in the vortex showed that the flow was unsteady. The vortices emanating from the smaller clearances were observed to wander or meander spatially and to develop kinks more than the vortices emanating from the larger tip clearances. This observed unsteadiness has a significant effect on the time mean size and velocity distribution of the vortex as measured with the LV employing the field point measurement technique. In order to obtain an estimate of the true size and velocity distribution, computational experiments were conducted which modelled a periodically wandering vortex and the LV measurement process. The computational and experimental results show good agreement, including a broadened and reduced tangential velocity distribution. In this paper, the end-wall vortex LV measurements are presented, and the method of analyzing the vortex wandering is described. 相似文献
34.
Ruhayel RA Zgani I Berners-Price SJ Farrell NP 《Dalton transactions (Cambridge, England : 2003)》2011,40(16):4147-4154
The aquation profiles of two novel dinuclear polyamine-linked, platinum-based antitumour complexes [{trans-PtCl((15)NH(3))(2)}(2){μ-((15)NH(2)(CH(2))(6)(15)NH(2)(CH(2))(6)(15)NH(2))}](3+) (BBR3007, 1,1/t,t-6,6, 1) and [{trans-PtCl((15)NH(3))(2)}(2){μ-((15)NH(2)(CH(2))(6)(15)NH(2)(CH(2))(2)(15)NH(2)(CH(2))(6)(15)NH(2))}](4+) (BBR3610, 1,1/t,t-6,2,6, 1') have been probed using 2D [(1)H, (15)N] HSQC NMR spectroscopy. Reported herein are the rate constants for the hydrolysis of 1 and 1', as well as the acid dissociation constants of the coordinated aqua ligands in their aquated derivatives. The aquation and anation rate constants for the single step aquation model in 15 mM NaClO(4) (pH 5.4) at 298 K are, for 1, k(1) = 7.2 ± 0.1 ×10(-5) s(-1), k(-1) = 0.096 ± 0.002 M(-1) s(-1) and, for 1', k(1) = 4.0 ± 0.2 × 10(-5) s(-1), k(-1) = 1.4 ± 0.1 M(-1) s(-1). The effect of the linker backbone (Pt(tetra(m)mine vs. polyamine) was evaluated by comparison with previous data for the trinuclear complex [{trans-PtCl(NH(3))(2)}(2)(μ-trans-Pt(NH(3))(2){NH(2)(CH(2))(6)NH(2)}(2))](4+) (1,0,1/t,t,t or BBR3464). The pK(1) for 1,0,1/t,t,t (3.44) is closest to that of 1 (3.12), while the pronounced difference for 1' (4.54), means that 1' is the least aquated of the three complexes at equilibrium. pK(a) values of 5.92 were calculated for the aquated forms of both 1 and 1', which are 0.3 pK units higher than for either 1,0,1/t,t,t, or the dinuclear 1,1/t,t. The higher pK(a) values for both polyamine-linked compounds may be attributed to the formation of macrochelates between the central NH(2) groups and the {PtN(3)O} coordination sphere of the aquated species. 相似文献
35.
E.J. Farrell 《Discrete Mathematics》1977,18(2):149-153
Chvátal gave a necessary condition for a partition to have a planar realization. It is of interest to find: (i) partitions which satisfy the condition of the theorem but have no planar realization, and also (ii) partitions which satisfy the condition and have only planar realizations. We give a list of all such partitions with 6, 7, 8 and 9 elements. We also give an algorithm for generating all graphs with a given partition, an algorithm for generating all subcompositions of a given composition and some general classes of partitions which have planar realizations only and some which have non-planar realizations only. 相似文献
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Methyl fluorosulphonate and triethyloxonium tetrafluoroborate (which is less reactive) have been found to give four distinct types of reaction with transition metal complexes, viz. (a) halogen abstraction, (b) oxidative-addition, (c) alkylation of the coordinated ligands, and (d) oxidation at the metal atom. 相似文献
39.
Harris AL Yang X Hegmans A Povirk L Ryan JJ Kelland L Farrell NP 《Inorganic chemistry》2005,44(26):9598-9600
Charge delocalization (6+ to 8+) in "noncovalent" linear trinuclear platinum complexes produces compounds with cytotoxicity in some cases equivalent to cisplatin. The cellular uptake of a novel 8+ compound is greater than that of neutral cisplatin as well as other multinuclear Pt compounds. 相似文献
40.
Nineteen years have elapsed since Baule and McFee1 first recorded a biomagnetic field, that of the human heart. Progress during most of this time has been slow and the overall impact of biomagnetism is still small. However, a number of recent developments have demonstrated a research and clinical potential that has quickened interest in the area. A recent general review2 and a comprehensive volume of research papers3 together provide an excellent overview of the whole field and we shall refer frequently to both of them. A brief introduction should serve to establish the specific focus of the present review. 相似文献