Discussion carbenes

1
Discussion - carbenes
2
Problem 1

• Circle the correct answer and explain your
  choice
• Faster reductive elimination
• More prone to b-hydride elimination

3

• More reactive toward associative substitution by
  an associative pathway
• More prone to migrate in a b-migratory insertion

4
Problem 2

• When PEt3 reacts with Mo(CO)6, the final product
  is fac-Mo(CO)3(PEt3)3. Substitution goes no
  further than trisubstitution. Give two reasons
  why this might be so. Account for the
  stoichiometry of the product.

5
Problem 3

• In which direction would you expect a late
  transition metal hydride to undergo insertion
  with CH2CF2 to give the most stable alkyl
  product?

6
Problem 4

• Which of the methods (a) to (e) would be suitable
  for solving parts 1-5 mentioned below? (a) X-ray
  crystallography (b) 1H NMR spectroscopy (c) 31P
  NMR spectroscopy (d) IR spectroscopy (e)
  magnetic moment determination. If you cite more
  than one method, indicate which method you would
  use first.
• characterizing a cyclometallated Ph2PC6H4
  complex
• characterizing a dihydrogen complex

7

• determining the stereochemistry of M(CO)2(dppe)2
  (dppe Ph2PCH2CH2PPh2)
• comparing the relative donor properties of a
  series of ligands L in LNi(CO)3
• finding out whether a given NiCl2(PR3)2 complex
  were square planar or tetrahedral in solution.
  How would you interpret the data?