University of Texas

CH 431

Experimental Method, Calculations, and Yield In this experiment, the following materials were used: toluene, dichloromethane (DCM), triphenylphosphine (PPh3), methanol, piperidine. Part one of the experiment also required Mo(CO)6, which is toxic and can cause severe harm to the body system. Additionally, DCM and PPh3 are irritants to the respiratory system. [Mo(CO)4(pip)2] was synthesized using the below procedure. A Schleck flask was purged with N2 for 5 minutes, after which 3.78 mmol Mo(CO)6 was added. 40 mL toluene and 10 mL piperidine were added into the flask, and the reaction was refluxed under N2 at 140°C for one hour. The reaction was subsequently cooled for two minutes, and the precipitated complex was collected via vacuum filtration and washed with hexanes. The solid was dried, and an IR spectrum was collected. [Mo(CO)4(PPh3)2] was synthesized using 0.5 mmol of the [Mo(CO)4(pip)2] from the previous step. Dry DCM (10 mL) and 1.15 mmol of PPh3 were added into the flask under N2 gas, and the mixture was heated to 35°C for 15 minutes. The reaction was cooled and the resulting precipitate was filtered, after which the filtrate was placed back into the flask. Using a vacuum line and a rubber septum, the volume in the flask was reduced by half. MeOH (10 mL) was added, and the flask was placed into an ice bath for 15 minutes, during which a yellow precipitate crystallized out. The complex was collected by vacuum filtration and washed with 10 mL of MeOH. The solid was dried and an IR was taken. The thermal isomerization of [Mo(CO)4(PPh3)2] was not successfully completed, as there was insufficient product from part two of the experiment. An IR was provided by the TA. Results and Discussion The synthesis of [Mo(CO)4(pip)2