1. cis-PtCl2(PEt3)2 is stable in a benzene solution. However, the addition of a small amount of excess PEt3 catalyzes equilibrium between the cis and trans isomers.
a) Why is free PEt3 required to catalyze the isomerization?
b) Show the sequence of steps involved in the isomerization.
2. The reaction: Cr(CO)6 + PR3 – Cr(CO)5(PR3) + CO
has the two term rate law: d[Cr(CO)3(PR3)]/dt = k1[Cr(CO)6] + k2[Cr(CO)6][PR3]
Consider the possible mechanisms for this reaction and give an explanation for the presence of the two terms.
3. Determine how each of the following modifications should affect the rate (faster, slower, or no change) of ligand substitution for a square-planar Pt complex. Circle your choice and provide
a brief explanation (no more than 1 sentence).
a) Changing a trans ligand from H to Cl
b) Changing the leaving group from I- to NO3-
c) Changing the entering ligand from Cl- to SCN-
d) Adding a bulky substituent to a cis ligand
e) A change in reaction solvent from CH2Cl2 to CH3OH
f) A change in the metal ion from Pt2+ to Pd2+
4. Determine how each of the following modifications should affect the rate (faster, slower, or no change) of a dissociative substitution reaction for a generic octahedral complex ([ML6]n+).
Circle your choice and provide a brief explanation (no more than 1 sentence).
a) An increase in the overall charge on the complex
b) Changing the leaving group from Cl- to NO3-
c) Changing the entering ligand from Cl- to SCN-
d) Changing the leaving group X from NH3 to en
5. Calculate the LFSE (in terms of Δo) for each of the complexes below and predict whether they
should be inert or labile.
a. [Fe(H2O)6]3+ LFSE = ___________ Δo
b. [Cr(H2O)6]3+ LFSE = ___________ Δo
c. [Co(NH3)6]3+ LFSE = ___________ Δo
d. [Co(NH3)6]2+ LFSE = ___________ Δo
e. [Zn(H2O)6]2+ LFSE = ___________ Δo
