LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LH 18

B.Sc. DEGREE EXAMINATION – CHEMISTRY

SIXTH SEMESTER – APRIL 2007

CH 6601 – COORDINATION CHEMISTRY

 

Date & Time: 18/04/2007 / 9:00 – 12:00     Dept. No.                                                   Max. : 100 Marks

 

 

PART-A

ANSWER ALL QUESTIONS. EACH QUESTION CARRIES TWO MARKS

1. Calculate the CFSE for [Co(NH₃)₆]³⁺.
2. Draw the structure of (a) Et₂DTC and (b) 1,10-phenanthroline.
3. What is Irving-Williams series?
4. The thermodynamic stability of complexes of Sc(II), Mn(II), and Zn(II) is lesser than the corresponding complexes of the rest of the first row transition metals. Give reason.
5. What is nephelauxetic ratio? Mention its significance.
6. Octahedral complexes of Ni(II) are paramagnetic whereas its square planar complexes are diamagnetic. Explain.
7. For which of the configuration Jahn Teller distortion is detected, low spin d⁴ or high spin d⁶ in an octahedral geometry? Give reason.
8. Draw the structures of (pentaheptocyclopenadienyl)(allyl)(dicarbonyl)molybdenum and

[Cr(h⁶-benzene)(CO)₃].

9. How is trans-[Pt(NH₃)₂Cl₂] prepared?
10. Mention the biological roles of Co(II) and Cr(III).

PART-B

ANSWER EIGHT QUESTIONS. EACH QUESTION CARRIES FIVE MARKS 

11. Draw the crystal field splitting energy level diagram in tetrahedral complexes.
12. Discuss the photoisomerization reactions of coordination complexes.
13. Write a note on superoxide dismutase.
14. Discuss the template synthesis with any two examples.
15. How does the nature of the metal ion influence D_o of complexes?
16. Give an account of M-L covalency in transition metal complexes.
17. Discuss the associative mechanism of ligand substitution reactions in octahedral complexes.
18. Explain Static-dynamic Jahn Teller distortion with an example.
19. Give an account of the organometallic compounds of cyclobutadiene and their reactivity.
20. Account for the following: (a) metal carbonyls are thermally unstable and (b) organometallic compounds are formed by metals in their lower oxidation states.
21. Explain the structural features of Fe₂(CO)₉ and Co₂(CO)₈.
22. Explain the mechanism of alkene hydrogenation by Wilkinson catalyst.

 

PART-C

ANSWER FOUR  QUESTIONS. EACH QUESTION CARRIES TEN MARKS 

23. Discuss the active centre and function of nitrogenase enzyme.
24. Discuss the mechanism and evidences of inner-sphere electron transfer reactions in coordination compounds.
25. Discuss the structural features of Schiff base ligands and their ability to form metal complexes.
26. State Jahn teller theorem. Mention the consequences of Jahn Teller distortion. Explain Jahn Teller distortion in six-coordinate complexes with the aid of qualitative crystal field splitting energy level diagram.
27. Explain the following with examples: (a) oxidative-addition reaction, (b) insertion reaction, and

(c) reductive elimination reaction.

28. (a) Give an account of the failure of crystal field theory. (b) Construct the qualitative MO energy level diagram for an octahedral complex involving M-L sigma bond only.

 

 

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