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441.
One-pot synthesis of novel M2E2L2 type metallacycles [L(CO)3Re(μ-SeR)2Re(CO)3L] (1-5) was accomplished by oxidative addition of diaryl diselenide to low-valent transition metal carbonyl with monodentate pyridine ligands. In metallacycles 1-5, where L = pyridine ligand, R = C6H5, CH2C6H5, the pyridyl groups bonded to metal centres invariably adopted cis conformation due to π-π interaction whereas, in compounds 1a and 2a, the pyridyl ligands were oriented in trans conformation. When bulky phenyl groups are introduced at para position of pyridyl rings, as in case of metallacycle 3, the steric hindrance disrupts the soft interaction and resulted into the expansion of space in between two phenylpyridyl groups and created a void. The Metallacycles 1-5 have been characterised by elemental analysis, NMR, IR, absorption and emission spectroscopic techniques. Molecular structures of 1, 1a, 2, 2a, 3 and 4 were determined by single crystal X-ray diffraction analysis and the structural studies of 1, 2, 3 and 4 revealed that the pyridyl groups attached to the metal centres exhibited cis conformation, while 1a, 2a displayed trans conformation. 相似文献
442.
Manimaran B Thanasekaran P Rajendran T Lin RJ Chang IJ Lee GH Peng SM Rajagopal S Lu KL 《Inorganic chemistry》2002,41(21):5323-5325
Self-assembly of rhenium(I)-based molecular rectangles containing long alkyl chains has been achieved in one-pot synthesis by solvothermal methods. An enormous enhancement in the emission intensity, quantum yield, and lifetime of the rectangles has been observed when the solvent medium is changed from organic to aqueous. Addition of water favors the aggregation of Re(I) molecular rectangle resulting in the luminescence enhancement, and this phenomenon has been traced out using light scattering techniques. 相似文献
443.
Karina Jagielska-Wiaderek Henryk Bala Tadeusz Wierzchon 《Central European Journal of Chemistry》2013,11(12):2005-2011
Thick (400 µm) glow-discharge nitrided layers, TiN+Ti2N + αTi(N) type, have been produced on the Ti-1Al-1Mn titanium alloy. Using a progressive thinning method, the polarization characteristics at different depths of nitrided layers have been measured. From the plots of obtained potentiodynamic polarization curves the depth profiles of characteristic anodic and cathodic currents (at potentials corresponding to (a) hydride formation, (b) hydrogen evolution, (c) primary passivation, (d) oxygen evolution and (e) secondary passivation) as well as polarization resistance have been determined in 0.5 M Na2SO4 solution acidified to pH = 2. The anomalously high slope of the polarization curves in the cathodic region has been ascribed to the formation of titanium hydride. It has been shown that outer nitrided layers (up to 25 µm) exhibit excellent acid corrosion resistance owing to strong inhibition of the anodic process by TiN phase. Corrosion resistance of deeper situated layers gradually decreases and at depths of 250–370 µm the corrosion process is accelerated by presence of TiO2 precipitations. Nitrided layers, unlike the alloy core, allow oxygen evolution on the oxy-nitrided surface at potential of +1.6 V and at more positive potentials gradual transformation of the surfacial film into TiO2 takes place. Secondary passivation on nitrided titanium is less efficient than that in the absence of Ti-N species. 相似文献
444.
Muhammad D. Bala Author Vitae Author Vitae 《Journal of organometallic chemistry》2007,692(4):709-730
In this review organometallic chemistry reactions in the melt phase are described. As will be indicated this is a viable approach to make new and known complexes. Examples from the literature highlighting procedures used to generate melts and results that have been obtained in this area of synthesis are described. Clearly there will be limitations to the use of the melt phase, and these limitations are also discussed. 相似文献
445.
Transition Metal Chemistry - Four new Cu complexes bearing triazolylidene ligands 1-(R)-3-methyl-4-phenyl-1H-1,2,3-triazol-3-ium-5-yl: R?=?phenyl (2a), mesitylenyl (2b), propyl (2c),... 相似文献
446.
Aamodt K Abelev B Abrahantes Quintana A Adamová D Adare AM Aggarwal MM Aglieri Rinella G Agocs AG Agostinelli A Aguilar Salazar S Ahammed Z Ahmad N Ahmad Masoodi A Ahn SU Akindinov A Aleksandrov D Alessandro B Alfaro Molina R Alici A Alkin A Almaráz Aviña E Alme J Alt T Altini V Altinpinar S Altsybeev I Andrei C Andronic A Anguelov V Anielski J Antičić T Antinori F Antonioli P Aphecetche L Appelshäuser H Arbor N Arcelli S Arend A Armesto N Arnaldi R Aronsson T Arsene IC Arslandok M Asryan A 《Physical review letters》2012,108(9):092301
The yield of charged particles associated with high-p(t) trigger particles (8
3 GeV/c on the away side drops to about 60% of that observed in pp collisions, while on the near side a moderate enhancement of 20%-30% is found. 相似文献
447.
A novel MB‐SWNT‐sol‐gel nanocomposite material was prepared by the sol‐gel process incorporating a redox mediator and carbon nanotubes. The electrocatalytic properties of the nanomaterial based sensor toward NADH oxidation were studied by electrochemical measurements. Significant enhancement of oxidation current is obtained at electrodes modified by MB‐SWNT‐sol‐gel in comparison with the analogous carbon black and/or graphite composite modified electrode. The usefulness of the nanocomposite material as a matrix for immobilizing enzymes is also demonstrated. Analytical parameters of D ‐lactate biosensors with and without SWNT in the hybrid film were compared demonstrating that performance of the biosensor was significantly improved when introducing SWNT. 相似文献
448.
Zinc acetate derived precursor used in the present sol-gel synthesis of zinc oxide nanoparticles is described. The reaction product obtained before and after reflux of propanolic zinc acetate solution have been studied by UV-vis, photoluminescence and FT-IR studies which confirm the formation of oligomeric precursor Zn4O(Ac)6 (Ac=CH3COO). The formation of approximately 7 nm zinc oxide nanoparticles were confirmed by X-ray diffraction (XRD) and Transmission electron microscopic studies (TEM). The gaseous ammonia gas sensing characteristics of the nano-zinc oxide sensor showed high sensitivity compared to sensor fabricated with commercial zinc oxide powder. 相似文献
449.
Renu Bala Kare Narain Pathak 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(10):228
We have obtained expressions for single particle density and two particle density ofweakly interacting trapped quantum gases. These are valid for all temperature and in anydimension. These expressions have been simplified and expressed in terms ofnon-interacting single particle density. The ground fluctuations for T<Tcin grand canonical ensemble has been treated with care using the method of Kocharovskyet al. [Phys. Rev. A 61, 053606 (2000)]. Some numerical results are presentedin one and three dimension for isotropic harmonically trapped Bose gas with contactinteractions. It is seen that boson density decreases with increasing repulsiveinteractions. The expression for critical temperature is also shown to agree with earlierresult and is in accordance with experiments. 相似文献
450.