نتایج جستجو برای: sigma bond
تعداد نتایج: 93641 فیلتر نتایج به سال:
There has been considerable number of papers published related to Six Sigma applications in manufacturing and service organizations. However, very few studies are done on reviewing the literature of Six Sigma in all the areas including manufacturing, construction, education, financial service, BPOs and healthcare etc. Considering the contribution of Six Sigma in recent time, a more comprehens...
This paper reports the synthesis of a series of piperidones 1-8 by the Mannich reaction and analysis of their structures and conformations in solution by NMR and mass spectrometry. The six-membered rings in 2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-ones, compounds 1 and 2, adopt a chair-boat conformation, while those in 2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-ones, compounds 3-8, adopt...
By first-principle simulations we study the effects of molecular deformation on the electronic and spectroscopic properties as it occurs for pentacene adsorbed on the most stable site of Al(001). The rationale for the particular V-shaped deformed structure is discussed and understood. The molecule-surface bond is made evident by mapping the charge redistribution. Upon X-ray photoelectron spectr...
The new ligands, 1-(4-isopropyl phenyl)-4-(2-pyridyl)-1,2,3-triazole, 1 and 1-(mesityl)-4-(2-pyridyl)-1,2,3-triazole, 2 were prepared by the reactions of the respective azides with 2-ethynylpyridine following the "click method". These ligands together with the reported ligands 1-(phenyl)-4-(2-pyridyl)-1,2,3-triazole, 3 and 1-(benzyl)-4-(2-pyridyl)-1,2,3-triazole, 4 were reacted with palladium a...
The purpose of this experiment was to determine the hardness values of the hybrid layer and its surroundings through the continuous use of a microhardness measuring device. Black's Class V cavities were prepared in nine dog teeth. The cavities were divided into four groups according to the dentin adhesive system applied. The adhesive systems were: "Bond One System", "Liner Bond II sigma System"...
Ethynyl- and allenylphosphine-boranes have been prepared by addition at low temperature of borane on the free phosphine. Purification was performed by selective trapping in vacuo and the complexes were characterized by NMR and infrared spectroscopy and mass spectrometry. A kinetic stability lower than that of the corresponding free systems was observed. A series composed of these compounds and ...
The electron and proton transfer in phenol-imidazole-base systems (base = NH(2)(-) or OH(-)) were investigated by density-functional theory calculations. In particular, the role of bridge imidazole on the electron and proton transfer was discussed in comparison with the phenol-base systems (base = imidazole, H(2)O, NH(3), OH(-), and NH(2)(-)). In the gas phase phenol-imidazole-base system, the ...
The tetrachloride salt of uranium reacts with 1 equiv of the lithium ligand Li2[(C5Me4)2SiMe2] in DME to form the complex [eta5-(C5Me4)2SiMe2]UCl2.2LiCl.2DME (1), which undergoes a rapid hydrolysis in toluene to yield the dimeric bridged monochloride, monooxide complex [{[eta5-(C5Me4)2SiMe2]UCl}2(mu-O)(mu-Cl)*Li*1/2DME]2 (2). Metathesis of 2 with BuLi in DME gives the mono-bridged dibutyl compl...
To further explore the reactivity of the (C(5)Me(5))(-) ligand in the sterically crowded (C(5)Me(5))(3)M complexes, reactions with PhEEPh (E = S, Se, Te) have been examined. With M = La, Pr, Nd, Sm, and Y, PhSSPh reacts to form the expected reduction products, [(C(5)Me(5))(2)M(SPh)](2), but the major organic byproduct is not the sterically induced reduction product, (C(5)Me(5))(2). Instead, the...
We report transient grating measurements carried out on single crystals of bromine clathrate hydrates and on bromine dissolved in water. In all cases, excitation into the B-state of Br2 leads to prompt predissociation, followed by cage-induced recombination on the A/A' electronic surfaces. In liquid water, the vibrationally incoherent recombinant population peaks at t=1 ps and decays with a tim...
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