Students will work in groups of three.  This experiment will involve the synthesis of an air-stable compound, Ru(dmso)₄Cl₂. The difficulty in the preparation is the fact that the intermediate in the reaction is air sensitive.  To prepare this compound, students will use both modified Schlenk line techniques and microwave synthesis techniques.  The students will compare the results of the two reactions.  Once prepared, the yellow product is to be characterized by IR, ¹H NMR and cyclic voltammetry*.  You will run the cyclic voltammetry in acetonitrile.  This experiment is modified from Evans, I. P., Spencer, A., Wilkinson, G., J. C. S., Dalton Trans., 1973, 204-209 and Harvey, A., Chiu, S.K., Snell, R., Draganjac, M., and Benjamin, E., J. Ark. Acad. Sci. 2009, submitted..

*note the NMR and CV instruments are not working.  Students are still responsible for explaining the theory behind the instruments.  A copy of the NMR spectrum will be given for the students to interpret.

1)  Find the MSDS for the compounds used to make Ru(dmso)₄Cl₂.  The starting reagents are ruthenium trichloride (ruthenium(III) chloride), dimethyl sulfoxide and acetone.

2) Preparation of Ru(dmso)₄Cl₂

Set up the apparatus as shown.  In the 50 mL two-neck flask, dissolve 0.2 g of RuCl₃ in 5 mL of dmso and place under N₂ by passing N₂ over the solution for 10 min.  This is done by removing the stopper from the second neck.  After 10 min., replace the stopper and bring the solution to reflux.  When the solution reaches reflux, note the time and reflux for 5 min. After the 5 min., remove the stopper and continue to heat under N₂ until the volume is half the original volume.  Replace stopper, remove from heat and let cool 5 - 10 min. before adding 20 mL of acetone.  A yellow precipitate should form at this point.  Filter and wash with acetone (two 5 mL portions).  Let dry before obtaining a yield.

3) Microwave synthesis

For the microwave reaction, place 0.1g RuCl₃^.xH₂O and 2 mL DMSO in a microwave reaction tube with a stir bar under N₂ or Ar and heat in the microwave reactor (see Dr. Benjamin, LSW339) to 135 ^OC for 10 min. Place in the refridgerator in LSW535 overnight. Filter the yellow precipitate and wash with acetone and air dried.  Obtain a yield.

4) Characterization of Ru(dmso)₄Cl₂

You are to run the ¹H NMR (instructions), IR and cyclic voltammetry (instructions) of your product. (See note above)

5) Cost analysis

You must detail how the compound will be synthesized, including diagram(s) for the synthetic apparatus(i) needed for your experiment.  The report must include a schematic of the reactions.  This schematic must be drawn using computer software of your choice.  The report must include a cost analysis of all materials needed to do the synthesis including NMR, CV, IR and Microwave reactor.  You will start with a lab that has two hoods, working gas, water and air jets, and plenty of bench and drawer space.  Everything else you must purchase.

Write up
     Each person in the group must submit a separate report.  The report must follow the guidelines on the Lab Report page and should include an introduction explaining how each instrument works (in theory) and what information each instrument gives about the compound.  The experimental section will describe the procedure used  for the preparation of the Ru(dmso)₄Cl₂.  Students should also include the manufacturer for the IR spectrophotometer and NMR spectrometer and the cyclic voltammetry apparatus.  Include the NMR spectrum, with integration and the cyclic voltammogram with the peak potentials (if any).  Discuss the peak assignments in the NMR of your compound.  Attach the MSDS for each compound and include the cost analysis.   This lab will be worth 60 points and is due by 5:00 pm Friday, April 17, 2009. No late reports will be accepted.
 

Hitachi R-1200 NMR	BAS CV-27 cyclic voltammeter

CHEM4204 Experiment list