Announcements

1. Make sure that you make progress on your formal report as well in terms of literature search and writing the parts that you completed already in the lab. The draft version of paper is due on 4-25-2008 at 5 pm. The draft version is worth 15 points, the final paper 45 points. For more information what the draft is supposed to contain see here. Late submission will receive less credit. The more of your work you submit here, the more feedback you will get, which will beneficial for the final version. We will try to return the reports by Monday.

2. The second quiz will be administered on Tuesday, April 15, 2008 at 12 pm covering the resolution step and the ligand synthesis. Please make sure that you show up on time. Otherwise you will not be allowed to take the quiz.

ATTN: Answers to the below questions are due at the start of your lab period; these answers should be part of your pre-lab write-up.

1. Referring to the synthesis and characterization of the Jacobsen catalyst, answer the following questions.

a. Why is Mn(OAc)₂*4 H₂O crushed prior addition to the ligand suspension?

b. Which compound is formed initially? Which color does this compound have?

c. Air is the oxidant in this reaction which is introduced via a glass tube. What does the student have to keep in mind here?

d. The reaction is monitored with TLC. What is used as mobile phase?

e. After extraction with water and sat. sodium chloride solution, heptane added to the organic phase. After heating the mixture gently for a while, he observes a brown precipiate. He places the mixture in an ice-bath. He then isolates the shiny brown crystals via vacuum filtration. However, he noticed that some more precipitate formed in the filter flask and that the filtrate is dark brown. How should the student proceed?

f. How can one rationalize this difference in C=N stretching frequencies in the ligand and the catalyst?