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991.
L. G. Lin Y. Wang J. W. Yan Y. Z. Yuan J. Xiang B. W. Mao 《Electrochemistry communications》2003,5(12):995-999
We report an in situ STM study of a potential-dependent long-range surface restructuring of Au(1 1 1) electrode in neat 1-butyl-3-methylimidazolium tetrafluoroborates (BMIBF4) ionic liquid. Au(1 1 1) undergoes a significant long-range surface restructuring upon cathodic excursion to −1.0 V vs. Pt quasi-reference. The restructuring involves the formation of tiny pits, which then develops into a stable worm-like network with an average width of the network grids 2 nm. Electrochemical annealing occurs at the cathodic limit with the presence of a reduction product of cation BMI+. A smooth surface is recovered with the appearance of the typical (√3 × 22) reconstruction of Au(1 1 1). The surface restructuring is reestablished upon anodic excursion to −1.3 V after the adsorbed reduction product is oxidized. The long-range surface restructuring phenomenon is tentatively explained as a result of partial charge transfer to the weakly adsorbed BMI+, which reduces the metal–metal cohesive energy. In addition, the synergetic effect of the counter anion BF4− may also be involved. The results provide a knowledge of Au(1 1 1) electrode behavior in the neat ionic liquid and are beneficial to understanding in situ STM results involving surface morphological changes in such a media. 相似文献
992.
CompoundsformedfromCu ,AgandAuwithdithio lateligands ,suchasthedialkyldithiocarbamate (DTC) ,mercaptothiazoline (HMT)anddialkyldithiophosphates(DDP) ,haveplayedanimportantroleintechnology .1Cu(I) Sclustersalsohavebeenimplicatedinbiologyasan ti oxidants .2Thecuban… 相似文献
993.
Novel furo, thieno and pyrrolo[2,3‐b]pyrazole cyanine dyes were synthesized. The structure‐photosensitization properties correlation of the dyes were examined in 95% ethanol solution by absorption spectroscopy. The chemical structure of the starting biheterocyclic compounds and their derived cyanine dyes were confirmed by elemental analysis, IR and 1H NMR spectroscopy. 相似文献
994.
Hoong‐Kun Fun Qingli Hao Jiang Wu Xujie Yang Lude Lu Xin Wang Suchada Chantrapromma Ibrahim Abdul Razak Anwar Usman 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):m87-m88
In the structure of the title compound, [CuII(en)2][(EtO)2P(S)S]2 (en is ethylenediamine) or [Cu(C2H8N2)2](C4H10O2PS2)2, the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethylenediamine molecules. The diethyl dithiophosphate moieties, (EtO)2P(S)S?, act as counter‐anions. 相似文献
995.
Tao-Chin Lin Wang Louis J. Cornio S. P. Markey 《Journal of the American Society for Mass Spectrometry》1996,7(3):293-297
A new liquid chromatography-mass spectrometry technique is described that utilizes a particle beam interface to transport and deposit desolvated analyte molecules onto a target surface that is bombarded by a primary beam of massive multiply charged glycerol cluster ions to generate secondary ions for mass analysis. The massive cluster ion beam is generated by electrohydrodynamic emission from a solution of 1. 5-M ammonium acetate in glycerol. In the present instrumental configuration the massive cluster ion gun is placed above the target probe and the particle beam interface is connected through a side port of the mass spectrometer. The massive cluster ion beam and particle beam are intercepted by a target surface substituted for a conventional ion volume. The target surface is positioned such that it is ~ 45 ° to the primary cluster ion beam, the particle beam, and the mass analyzer axis. This geometric orientation represents a compromise among the performances of these three elements. The feasibility of this liquid chromatography-particle beam on-line with massive cluster impact is demonstrated by flow injections of acetylcholine chloride and gramicidin S. Spectra generated from this preliminary study indicate promise for routine liquid chromatography-mass spectrometry of polar compounds by using a robust inlet and an effective generation of secondary ions without an added matrix. 相似文献
996.
ExtensivestudiesofradiationorchemicalinjuryofbiologicaltargetmoleculesdemonstratethatOHradical,themostreactiveoxygenspecies,reactswithbiologicalmacromolecules,suchasDNA,inducingbasealterations,basicsites,andstrandbreaks,resultedinvariouspathogenesis,such… 相似文献
997.
(Z, E)-9, 11-Tetradecadienyl-l-acetate (1), a major component of the sex pheromone of Spodoptera litura (F.), and (Z, E}-9, 11-pentadecadienyl-1-acetate (2) were synthesized by the Wittig reaction between (E)-2-alkenal (3) and the ylid derived from 9-hydroxynonyltriphenylphosphonium bromide (4). 相似文献
998.
The UV light irradiation of isoniazid (I) in methanol four products, isonicotinic acid (II), isonicotinamide (III), N, N′-bis(isonicotinic acid)hydrazide (IV) and isonicotinaldehyde isonicotinyl hydrazone (V), in ethanol three products, (III), (IV) and acetaldehyde isonicotinyl hydrazone (VI) were isolated and identified. Also, the photoreaction mechanism of isoniazid in methanol and ethanol were discussed. 相似文献
999.
1000.
Two novel sesquiterpene dimers, compounds 1 and 2 , were isolated from the rhizome of Ligularia virgaurea, together with the six known sesquiterpenoids 3 – 8 . Their structures were established by physico‐chemical and spectroscopic methods, especially by means of 1D‐ and 2D‐NMR as well as HR‐MS analyses. A mechanism based on a classical Diels–Alder cyclization is proposed for the formation of the dimer 1 from the precursors 8 and the quinone form of 6 (Scheme). 相似文献