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 a slow air stream passed through the reaction mixture? Draw a sketch the reaction setup.

b. The reaction mixture is yellow initially and then turns dark brown. Explain briefly.

c. Where do you expect to observe the C=N-stretching frequency for the ligand and the catalyst? Rationalize the differences.

d. What is the melting point of the catalyst?

2. The following questions refer to the catalyst design.

a. Why are there two tert. butyl groups attached to the benzene ring? Could you use two methyl groups instead?

b. Which advantage do you see in using metal-salen complex for catalysis as compared to the metal alone?

c. Which oxidation state does the Mn-atom have in the neutral complex?

d. Would the (R,S)-form of the diamine (instead of the (R,R)-form) be a good choice as bridge in the catalyst?