Transition Metal Catalysis

Experiment 5: Transition Metal Catalysis 1. trigger This experiment aims to give transition metal palladium gas for diarylacetylenes synthesis. In general, the procedures constitute of 2 steps: the synthesis of gas pedal precursor for dynamical species Pd(PPh3)4 and the preparation of alkyne. Bases on the previous studies, at that place are two well-known reactions to synthesize diarylacetylenes. The first tell apart discovered by Castro involves the use of copper acetylides. These reagents are fain by discourse of an aqueous ammonia ascendent of cuprous iodide with an fermentation alcohol root word of monosubstituted aryl acetylenes. (eq.1) (1) The cuprous acetylides are because hard-boiled with aryl iodides in refluxing pyridine under nitrogen atmosphere to stoichiometrically generate diaryl acetylenes. (eq. 2) (2) By using amines as solvents and CuI as a co-catalyst, the method was ameliorate to enable introducing alkyl group sub stitutent to the triple bond at room temperature. The second method, which was use in this experiment, was introduced by Cassar and Heck by utilizing palladium colonial to turn the reaction. (eq. 3) (3) 2. Experimental Section 2.

1The catalytic Precursor Preparation A mixture of palladous chloride (0.0384 g, 0.216 mmol) and sodium chloride (0.0303 g, 0.518 mmol) in water (1.5 ml) was stirred and warm up to about 50ºC. The solution was allowed to cool down. A solution of triphenylphosphine (0.1280 g, 0.488 mmol) in ethanol (20 ml) was accordingly prepared. The palladous chloride solution was added dro pwise to the triphenylphosphine solution and! stirred simultaneously. The resultant slurry was then warmed to about 50ºC over 30 legal proceeding to coagulate the precipitate. The mixture was cooled, filtered, and washed with water, acetone, and ether. The harvest was dried-out in a 50ºC oven for 3 minutes to ultimately generate yellow solid palladium complex product (0.1302 g, 86%). 2.2The...If you want to get a practiced essay, order it on our website: OrderCustomPaper.com

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