Problems Set - Meeting #4

The second quiz will administered on Tuesday April, 20, 2004 at 8 am in CS 50. Please make sure that you are on time in order to take full advantage of the time allotted for the quiz.

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.

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 ligand, answer the following questions.

a. How is the diamine obtained from the ammonium salt (3) in this reaction? Provide a balanced chemical equation.

b. Why does the IR spectrum of the ligand not show the characteristic broad OH-peak at 3400 cm^-1 despite the fact that the product possesses two OH-groups?

c. Where do you expect the C=N-stretching frequency to appear in the IR spectrum? Do you expect this peak to be stronger of weaker than the C=O mode? Explain briefly.

d. Based on the information given in the reader, what has to be considered when acquiring the UV-Vis spectrum of the ligand?

e. Which concentration (in percent) should be used for the polarimetry experiment? What is the expected specific optical rotation for the pure (R,R)-form of the ligand?

f. How many signals do you expect to observe for ligand in the ¹³C-NMR spectrum? In which range do they fall?

g. Why is saturated sodium chloride solution used during the work-up?