Propose a reasonable mechanism for the reaction - propose a

Question

1. Which statement concerning optical isomerism in coordination complexes is wrong:

(a) Optical isomerism cannot occur if the ligands in a complex are all the same

(b) Optical isomerism can occur if the ligands in a complex are all different

(c) Optical isomerism requires a plane of symmetry to be absent in the structure

 2. Propose a reasonable mechanism for the following reaction.(Show the full mechanism)

3. Propose a reasonable synthesis of alcohol 1 from (i) benzaldehyde 2 and (ii) acetophenone(Show the full mechanism).

4. The stepwise formation constants (logK₁ - logK₆) for the below reaction are 3.5, 2.7, 1.9, 1.0, 0.1, and - 0.9 respectively. Use this information to help answer (i) - (iii) (Please show your working in an easy to understand format)

            [M(H₂O)₆]²⁺     +     6NH₃     =     [M(NH₃)₆]²⁺     +     6H₂O

(i) Discuss the reaction in terms of the ease of each successive step and sketch the dominant product or products of the overall reaction

(ii) Deduce the overall formation constant (log b) for the reaction

(iii) Suggest with detailed explanation approximate values of logK₁, logK₂, and    logK₃ for the corresponding reaction of [M(H₂O)₆]²⁺ with ethylenediamine (en) [H₂NCH₂CH₂NH₂] and sketch the dominant product of this reaction.  

5. Use the examples and data for the aqueous reactions 1 and 2 below to help answer (i) - (iv) underneath (en = ethylenediamine) (Please show your working in an easy to understand format)

[M(H₂O)₆]²⁺   +   6 NH₃    =                [M(NH₃)₆]²⁺     +     6H₂O        (reaction 1)

[M(H₂O)₆]²⁺   +   3 en                =       [M(en)₃]²⁺        +     6H₂O        (reaction 2)

stepwise formation                  

constant (log k_n)                      reaction 1                    reaction 2

log k₁                                       + 5.3                            + 12.6

log k₂                                                    +4.0                             + 9.8

log k₃                                                    + 3.0                            + 6.1

log k₄                                                    + 1.9                            -

log k₅                                                    + 0.1                            -

log k₆                                                    - 2.1                             -

(i) What does the data reveal about the trend in the relative ease of ligand substitution for reaction 1. Explain how this trend could have been predicted from a simple statistical consideration for any such ligand substitution reaction.

(ii) Why are only 3 steps shown for the reaction with en (reaction 2). Explain why the 3 values of log k shown for them are much higher than anything seen for reaction 1.

(iii) Sketch the detailed structure of the major product complex of reaction 2