last updated Friday, May 15, 2009

Meeting 15 (Acetyl Ferrocene)

Important Announcements:

1. The proposal is due on May 22, 2009 at 5 pm in YH 3077 E (If you have problems please see me asap!). Late proposal will not be accepted and will lead to an automatic "F"-grade for the course. The important references have to be attached to the proposal. The proposal has to be submitted to turnitin.com as well (same course ID as before) by 11 pm on May 25, 2009 only one per group! Make sure that you have an electronic copy of your proposal with you.

2. The next quiz (=quiz 7) will be administered on May 21, 2009 at 12 pm. It will cover ferrocene, acylation of ferrocene and organometallics. Make sure that you show up on time, which means that you have to be seated by 11:55 am. Otherwise you will not be allowed to take the quiz.

3. In the lab, you will only carry out the acylation of ferrocene, but not the synthesis of ferrocene. This part will be done individually and not in groups.


Homework assignments (due May 19/20, 2009)

1. Referring to the synthesis of ferrocene.

a. Why is cyclopentadiene significantly more acidic than cyclopentane?

b. Cyclopentadiene is not commercially available. Explain why. How is it obtained from the commercial source?

c. A student uses FeCl₃*6 H₂O as iron source. Why would this be a poor choice?

d. Why is DMSO used as solvent for the reaction?

e. KCp dissolves well in polar solvents while FeCp2 does not. Rationlize this observations.

2. Referring to the synthesis of acetyl ferrocene, answer the following questions.

a. Identify the electrophile and the nucleophile in this reaction.

b. How is the electrophile generated in the lab? Show pertinent chemical equation(s).

c. After the reaction is completed, the reaction mixture is poured into a solution of sodium acetate. Explain why.

d. Why is it important to "neutralize" the organic layer before performing the column chromatography step? Which pH-value is the student looking for here?

e. The crude product has to be chromatographed here. What is used as stationary phase? What is the mobile phase?

f. In many cases, the student observes a dark blue or dark green color at some point during the work-up. Rationalize this observation.

g. The ¹H-NMR spectrum of acetyl ferrocene exhibits three signals at from d = 4-5 ppm. Rationalize this observation.