نتایج جستجو برای: olefin
تعداد نتایج: 2960 فیلتر نتایج به سال:
The aryl-functionalized pyridylamine 2-(i)PrC(6)H(4)N(H)py (1) and bis(2-pyridyl)amines of the type ArN(py)(2) for Ar = Mes (2), 2,6-Et(2)C(6)H(3) (3), 2-(i)PrC(6)H(4) (4), 2,6-(i)Pr(2)C(6)H(3) (5), and 1-naph (6), have been prepared by the palladium-catalyzed cross-coupling of substituted anilines with 2-bromopyridine, and have been characterized by (1)H and (13)C NMR NMR, FTIR, MS, and TGA. C...
Extending the scope of biocatalysis to important non-natural reactions such as olefin cyclopropanation will open new opportunities for replacing multi-step chemical syntheses of pharmaceutical intermediates with efficient, clean, and highly selective enzyme-catalyzed processes. In this work, we engineered the truncated globin of Bacillus subtilis for the synthesis of a cyclopropane precursor to...
The mechanism of olefin substitution at palladium(0) has been studied, and the results provide unique insights into the fundamental reactivity of electron-rich late transition metals. A systematic series of bathocuproine-palladium(0) complexes bearing trans-beta-nitrostyrene ligands (ns(X) = X-C(6)H(4)CH=CHNO(2); X = OCH(3), CH(3), H, Br, CF(3)), (bc)Pd(0)ns(X) (3(X)), was prepared and characte...
[reaction: see text] A template containing two secondary dialkylammonium ion recognition sites for encirclement by olefin-bearing dibenzo[24]crown-8 derivatives has been used to promote olefin cross metatheses with ruthenium-alkylidene catalysts. For monoolefin monomers, the rates of metatheses and yields of the dimers are both amplified in the presence of the template. Likewise, for a diolefin...
Density functional theory calculations have been used to explore the potential of Fe-based complexes with an N-heterocyclic carbene ligand, as olefin metathesis catalysts. Apart from a less endothermic reaction energy profile, a small reduction in the predicted upper energy barriers (≈ 2 kcal mol(-1)) is calculated in the Fe catalyzed profile with respect to the Ru catalysed profile. Overall, t...
[5]Catenanes were synthesized by olefin metathesis dimerization. The reaction of pseudorotaxanes, which were derived from a [2]catenane and one equivalent of an ammonium salt bearing two terminal olefins in dichloromethane, with a catalytic amount of Grubbs catalyst afforded linear [5]catenanes in 12% yield. Intermolecular and intramolecular olefin metathesis reactions were controlled by the le...
A series of bimetallic organo-group 4 "constrained geometry" catalysts and binuclear bisborane and bisborate cocatalysts have been synthesized to probe catalyst center-catalyst center cooperativity effects on olefin enchainment in homogenous olefin polymerization and copolymerization processes. Significant nuclearity effects are found versus mononuclear controls, and the effect can be correlate...
The investigation of occupational Noise in a Petrochemical industry has been carried out. The noise levels were measured following standard procedure using calibrated sound pressure level meter Smart Sensor (Model AR854), Noise levels were measured at Gas plant, Olefin plant area, and Preform machine area of a petrochemical industry then questionnaires were designed to determine the health impa...
The dynamics of iron tetracarbonyl olefin complexes has been investigated using two-dimensional infrared (2D-IR) spectroscopy. Cross peaks between all CO-stretching bands show that the CO-stretch modes are coupled, and from the cross-peak anisotropies we can confirm previous assignments of the absorption bands. From the pump-probe delay dependence of the diagonal peaks in the 2D-IR spectrum we ...
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