Starter Draw [Cu(EDTA)]2- Draw the two optical isomers of [Co(H2O)2(NH2CH2CH2NH2)2]2+

Q. What shape? edta

L.O.: Describe the process of ligand substitution. Describe examples of ligand substitution using [Cu(H2O)6]2+ and [Co(H2O)6]2+ with ammonia and chloride ions.

Common ligand substitution reactions Reaction No. Aqueous complex Complex with substituted ligands 1 [ Cu(H2O) 6]2+ (aq) Pale blue solution [Cu(NH3) 4(H2O) 2]2+ (aq) Deep blue solution 2 [CuCl 4]2- (aq) Yellow solution 3 [ Co(H2O) 6]2+ (aq) Pink solution [CoCl 4]2- (aq) Blue solution

Ligand substitution and equilibria Looking at the table you have just drawn, describe and explain would happen to the position of the equilibrium if: You increased the amount of HCl you added to no. 2 You added more water to no. 1. If the forward reaction in no. 2 was exothermic and you heated the solution. EXTENSION: You added EDTA to number 3.

The Haem group in Haemoglobin (Hb)

Iron and the heme prosthetic group

How the haem group binds to the heamoglobin protein

The Haem group The iron (II) ion forms four bonds with the haem group, one with the O2 and another with the protein part of the Hb The coordinate bond with the O2 is a temporary bond and allows Hb to acts as a transporter molecule However, CO can bind instead of O2 and it does so irreversibly, rendering the haem molecule it is bound to unable to carry oxygen

Equilibrium constant, Kc For each of the three equilibriums in your table write out the expression for the equilibrium constant

Stability constant For equilibriums involving complexes we use the term stability constant instead (Kstab) A large Kstab means that the complex is very stable, and so suggests that the ion is very easily formed NB: We usually do not include water in the stability constant because usually it is such excess that its concentration effectively remains the same throughout.

Writing the units to Kstab Worked out in just the same way as in Kc Work out the units for each of the Kstab expressions you have worked out