The point and purpose of this experiment is to explore the different modes of stretching that are allowed by a metal with a three-carbonyl ligand system. The ligand that we are going to study is an arene, which allows for it to have different properties as opposed to the normal metal ligand groups. With the ligand that we are going to create, we will study the stretching modes by IR and observe that there is one symmetric stretching mode and two asymmetric stretching modes. With a mathematical approach called group theory, we will observe that when the IR is taken there will only be two bands observed, one of the symmetric stretch and one representing the two asymmetric stretches. Along with the number of bands observed, we will also be able to calculate the angles between the CO ligands.
In order to carry out this experiment, we needed to set up the apparatus correctly. We forgot to grease the joints, which later on would prove costly. A couple of corrections were made to this lab. There would be no sublimation by the compound and we wouldn't use the rotovap with a second trap. Also when adding the hexanes to the solution, we where to keep it under a nitrogen stream as much as possible.
First, we weighed out 2.0420g of Mo(CO)6 and measured out 10mL of mesitylene in a 50mL three neck round bottom flask with a side arm. The compound will reflux in the reflux condenser, which was connected into the center arm and cooled by the air in the room. Flush the unit with nitrogen for 5 minutes to make sure that there is an inert atmosphere. Add compound and mesitylene in round bottom and heat on mantle for 30 minutes and then remove from heat. We allowed the mixture cool to room temperature and then added 15mL of hexanes under nitrogen. After the precipitation was complete, we filtered by vacuum suction and washed with 5mL of hexane. The product was impure so we dissolved it in 10mL of
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