Combined use of elevated pressure in the liquid phase (15 kbar), a metal template and the sulfur nucleophilicity of [Pt2(μ-S)2(P-P)2] (P-P = diphosphine or 2 · monophosphine) facilitates the one-pot synthesis of 3,8-dibenzo-1,6-dithiacyclodecane. Under r.t.p., nucleophilic addition of [Pt2(μ-S)2(P-P)2] [P-P = 2 · PPh3; Ph2P(CH2)nPPh2, n = 2, 1,2-bis(diphenylphosphino)ethane (dppe), 3, 1,3-bis(diphenylphosphino)propane (dppp)] with α-α′-dichloro-o-xylene would terminate as a dithiolato bridged cation viz. [Pt2(μ-SCH2C6H4CH2S)(P-P)2]2+. Under high pressure (15 kbar) at r.t., these stoichiometric reactions progress via a “catalytic-like” pathway to yield 3,8-dibenzo-1,6-dithiacyclodecane (up to 35%), and a series of mechanistically relevant intermediates and byproducts. The dithiolated intermediates [Pt2(μ-SCH2C6H4CH2S)(P-P)2]2+ for PPh3 and dppp have been isolated as complexes and their crystal structure determined. The formation of 3,8-dibenzo-1,6-dithiacyclodecane demonstrates a convenient synthetic strategy over the multi-step synthesis of this macrocyclic dithioether. 相似文献
Time-of-flight secondary ion mass spectrometry (TOF SIMS) has been used in conjunction with a mass spectrometry cleavable linker to determine the percent conversion of reactions that were conducted site-selectively on an addressable microelectrode array. When combined with fluorescence techniques for analysis of the reactions, the TOF SIMS experiment provides a means for optimization of both reaction confinement and reaction efficiency on the microelectrode arrays. 相似文献
In Li-ion technology, increasing electrode loading (thickness) is one approach to improve performance; however, this approach typically compromises power density and safety. To achieve the goal of decoupling energy and power density, a novel electrode architecture is proposed. The electrode design enhances uniform ionic current, especially in thick electrodes. A highly ordered and hierarchical (HOH) graphite anode concept was designed, fabricated, and tested for efficacy. The HOH electrodes consisted of ordered arrays of macro-scale line-of-sight linear channels made through laser ablation. SEM and Raman spectroscopy demonstrated that laser ablation is a feasible approach to fabricate HOH electrodes without affecting the graphite anode chemistry, respectively. A 65–120% improvement in charge rate acceptance (5.5 mAh/cm2) was achieved in the HOH electrodes compared to conventional electrodes. A restricted diffusion direct current polarization test determined that the HOH design improved ionic flow throughout porous electrodes. Altogether, the results of this study suggest that improved charge rate acceptance can be achieved by engineering electrode porosity to mitigate the effects of concentration polarization in high energy density graphite anodes. These findings can facilitate the development of higher energy and power density Li-ion batteries, while improving resilience against Li plating under severe charge conditions. 相似文献
We describe ColliderBit, a new code for the calculation of high energy collider observables in theories of physics beyond the Standard Model (BSM). ColliderBit features a generic interface to BSM models, a unique parallelised Monte Carlo event generation scheme suitable for large-scale supercomputer applications, and a number of LHC analyses, covering a reasonable range of the BSM signatures currently sought by ATLAS and CMS. ColliderBit also calculates likelihoods for Higgs sector observables, and LEP searches for BSM particles. These features are provided by a combination of new code unique to ColliderBit, and interfaces to existing state-of-the-art public codes. ColliderBit is both an important part of the GAMBIT framework for BSM inference, and a standalone tool for efficiently applying collider constraints to theories of new physics. 相似文献
A series of Ru(II) mixed-ligand complexes RuBr(2)(PPh(3))(2)(N-AyBzTh) (Ay = prop-2-enyl; BzTh = benzothiazol-2-ylidene) (4), RuBr(OAc)(PPh(3))(N-MeAyBzTh) (5), RuBr(OAc)(PPh(3))(N-MeBnBzTh)(2) (MeBn = 3-methylbut-2-enyl) (6) and RuCl(OAc)(PPh(3))(N-MeBnBzTh) (7) have been synthesized from Ru(OAc)(2)(PPh(3))(2) in one-pot condensation and ligand exchange reactions. X-ray single-crystal diffraction analysis revealed that they are neutral octahedral Ru(II) complexes with one or two N,S-heterocyclic carbene (NSHC) ligands and a coordinated (4, 5 and 7) or dangling (6) olefin arm. The system displays a range of self-selecting structural variations. Entry of the hybrid olefin-NSHC and halide ligands ejects either one (5, 6 and 7) phosphine ligand or keeps both phosphines (4) by replacing the acetate. It is also possible to accommodate two NSHC ligands by keeping the olefin pendant (6). Complexes 5 and 7 are isostructural with all different ligands on the coordination sphere. Complexes 4-6 are active towards transfer hydrosilylation showing good β(Z) selectivity, with the Ru(II) bearing acetate giving higher yields. 相似文献
Phosphorescent copper(I) complexes carrying 2,2'-bipyridyl derivatives and phosphine ligands have been prepared and fully characterised. The role of the bipyridyl as well as the phosphine ligands in defining the optical, as well as the chemical properties of the complexes, are discussed. The light emission of these complexes is investigated as a function of the molecular geometry: rigid complexes with restricted freedom to rearrange in the excited state are found to show a quantum yield of phosphorescence one order of magnitude higher than those complexes with no steric constraint. The complexes have been extruded in a polymer matrix as a proof of principle of their processability. 相似文献
Two-stage dilute acid pretreatment followed by enzymatic cellulose hydrolysisis an effectivemethod for obtaining high sugar
yields from wood residuessuchassoftwood forest thinnings. In the first-stage hydrolysis step, most of the hemicellulose is
solubilized using relatively mild conditions. The soluble hemicellu losic sugars are recovered from the hydrolysateslurry
by washing with water. The washed solids are then subjected tomoresevere hydrolysis conditions to hydrolyze approx 50% of
the cellulose to glucose. The remaining cellulose can further be hydrolyzed with cellulase enzyme. Our process simulation
indicates that the amount of water used in the hemicellulose recovery step has a significan tim pact on the cost of ethanol
production. It is important to keep water usage as low as possible while mainta ining relatively high recovery of solublesugars.
To achieve this objective, a prototype pilot-scale continuous countercurrent screw extractor was evaluated for the recovery
of hemicellulose from pretreated forest thinnings. Using the 274-cm (9-ft) long extractor, solubles recoveries of 98, 91,
and 77% were obtained with liquid-to-insoluble solids (L/1S) ratios of 5.6, 3.4, and 2.1, respectively. An empirical equation
was developed to predict the performance of the screwextractor. This equation predicts that soluble sugar recovery above 95%
can be obtained with an L/IS ratio as low as 3.0. 相似文献
Summary: We report a new method for the preparation of polyaniline nanoballs by using HAuCl4 as an oxidizing agent. During the reaction, aniline is oxidized and forms polyaniline whilst the hydrogen tetrachloroaurate is reduced and forms gold nanoparticles. These gold nanoparticles are found to decorate the nanoballs.
The resultant precipitate and corresponding TEM image of the gold‐nanoparticle covered polyaniline nanoball. 相似文献