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Chem 332 Organometallic Chemistry
Midterm Examination

Tuesday, April 1, 2003. Time allowed, 80 minutes. Total 80 points (plus 5 bonus points)

Note: I prepared the answers in rush. It may contain mistakes. Please let me know if you find obvious mistakes.

Section 1. Multiple Choices (28 points total). Select the most appropriate answers.
1.1. Which of the following ions or molecules can form complexes with a transition metal?
a) SiH4 b) CH2Cl2 c) benzene d) CH2=CH2
e) two of them f) three of them g) all of them h) none of them
(g)
1.2. Which of the following ions or molecules can be classified as -donors?
a) CH2=CH2 b) CN- c) OH- d) Cl-
e) two of them f) three of them g) all of them h) none of them
(e)

1.3. Which of the following complexes follows the 18e rule?




c) both of them d) none of them
(c)

1. 4. Assuming that the 18-electron rule applies, the M in the following complex is



(a)

1.5. Which of the following complexes would you expect to have the shortest C-O bond distance?

a) Ni(CO)4 b) [Co(CO)4]-

c) [Fe(CO)4]2- d) Pt(CO)4
(a)

1.6. Which of the following complexes would you expect to have the highest C-O stretching frequency?

a) Ni(CO)3(PPh3) b) Ni(CO)3(PMe3)

c) Ni(CO)3(PF3) d) Ni(CO)3(PPh2Me)
(c)

1.7. Which of the following complexes would you expect to have the strongest metal-alkyl bond?

a) (PPh3)3Rh-CH3 b) (PPh3)3Ir-CH3

c) (PPh3)3Rh-CF3 d) (PPh3)3Ir-CF3
(d)

1.8. Which of the the following ligand has the largest cone angle?

a) CO b) PMe3 c) PPh3 d) PCy3 (Cy = cyclohexyl)
(d)

1.9. Which of the following complexes would you expect to be thermally most stable?




(b)
1.10. Which of the following complexes would you expect to undergo -hydrogen elimination reactions most readily?



(c)

1.11. [OsH3(Ph2PCH2CH2PPh2)2]+ is known to contain a dihydrogen ligand (therefore it should be formulated as [OsH(H2)(Ph2PCH2CH2PPh2)]+. Which of the following compounds is least likely to contain a dihydrogen ligand?

a) [FeH3(Ph2PCH2CH2PPh2)2]+ b) [RuH3(Ph2PCH2CH2PPh2)2]+
c) ReH3(Ph2PCH2CH2PPh2)2 d) MnH3(Ph2PCH2CH2PPh2)2
(c)

1.12. Which of the following dissociative substitution reactions would you expect to have the highest reaction rate?

a) Cr(CO)5(PPh3) + CO --------> Cr(CO)6 + PPh3

b) Mo(CO)5(PPh3) + CO --------> Mo(CO)6 + PPh3
c) W(CO)5(PPh3) + CO --------> W(CO)6 + PPh3
d) Ni(CO)3(PPh3) + CO --------> Ni(CO)6 + PPh3

(d)
1.13. Which of the following reactions may be associative substitution reactions?

a) V(CO)6 b) Re(CO)4(NO) c) CpRh(CO)2

d) two of them e) all of them f) none of them

(e)

1. 14. The metal fragment Pt(PPh3)2 can bind a variety of olefins and acetylenes to give complexes of the type (olefin)Pt(PPh3)2 or (acetylene)Pt(PPh3)2. Which of the following organic mo