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On the category of oxidative addition, M. L. H. Green in 1970 reported on the photochemical insertion of tungsten (as a Cp 2 WH 2 complex) in a benzene C–H bond [7] and George M. Whitesides in 1979 was the first to carry out an intramolecular aliphatic C–H activation [8] Fujiwara's palladium- and copper-catalyzed C-H functionalization
Of academic interest, palladium acetate, iodine, and oxygen can be used to couple cyclohexyl amine and cyclohexyl isocyanide. [5] Yields of up to 67% have been achieved using this route: C 6 H 11 NC + C 6 H 11 NH 2 + O 2 → (C 6 H 11 N) 2 C + H 2 O. DCC has also been prepared from dicyclohexylurea using a phase transfer catalyst.
For radiolabeling, the pH of the 68 Ga containing generator eluate has to be raised from its initial value (depending on HCl concentration, pH 1–1.5) to pH 2–3.5 [11] using suitable buffers, such as sodium acetate.
C 7 H 14 N 2: Molar mass: 126.203 g·mol −1 Appearance Liquid Density: 0.806 g/mL Boiling point: 145 to 148 °C (293 to 298 °F; 418 to 421 K) Hazards GHS labelling:
A common way to synthesize an NHS-activated acid is to mix NHS with the desired carboxylic acid and a small amount of an organic base in an anhydrous solvent. A coupling reagent such as dicyclohexylcarbodiimide (DCC) or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) is then added to form a highly reactive activated acid intermediate.
For nitration, for example, fluorine directs strongly to the para position because the ortho position is inductively deactivated (86% para, 13% ortho, 0.6% meta). On the other hand, iodine directs to ortho and para positions comparably (54% para and 45% ortho, 1.3% meta). [12]
NOBS is the main bleach activator used in the U.S.A. and Japan. [4] Compared to TAED, which is the predominant bleach activator used in Europe, NOBS is efficient at much lower temperatures. At 20 °C NOBS is 100 times more soluble than TAED in water. [5]
In phosphors and scintillators, the activator is the element added as dopant to the crystal of the material to create desired type of nonhomogeneities. In luminescence , only a small fraction of atoms, called emission centers or luminescence centers , emit light.