Assignment 2 (Barron)
Chem 495: T-Metals

December 1st, 2003

Due date is December 15th, 2003.

1. Answer all questions.
2. Use diagrams where appropriate.
3. Remember the name of the reaction, the metal oxidation state and total electron count are important (hint - if you don't give them I can't give you any marks!).
4. Notice the number of points per question. This should provide a hint as to how much information is required in your answer.
5. No joint work.
6. Use black, blue pens ONLY. No pencil. Use of pencil results in an automatic failure.

Q.1. Suggest a mechanism by which the transformation between the Ni compounds given in class occurs (20 points).

Q.2. Which of the following compounds will be stable. To get full marks, I suggest you show working and rationalization (20 points).
(a) [Cr(C₆H₆)₂]+
(b) Ru(O)(Cp)Me₂
(c) W(CO)₂(pyridine)
(e) Cp₂Mo(C₂H₂)

Q3. The complex Rh(H)CO(PPh₃)₃ reacts with ethylene and CO in the presence of H₂ to give CH₃CH₂C(O)H. Describe the catalyst cycle and each reaction step (20 points).

Q4. Transition metal metathesis of olefins is a common catalyst system. However, other iso-lobal compounds will perform similar reactions. Suggest a catalyst cycle for the Cl₃P=NR catalyzed metathesis of RN=C=NR”. Note the different alkyl (R and R”) groups. (20 points)

Q5 If Pd(H)(Cl)L₂ (L = PPh₃) is used as a catalyst then ethylene (C₂H₄) and carbon monoxide (CO) are converted catalytically into a mixture of two products shown below. What is the catalytic cycle? Hint: the last step is the one that results in the two different products (20 points).