Stability constants
No description yet. This curated deck is ready for daily study.
Card preview (24)
What is a lewis base?
Ligand Electron pair donor
What is a lewis acid?
Metal Electron pair acceptor
What is binding affinity expressed as?
A numerical value
What is kinetic stability?
The rate of reaction Whether something is labile or inert
What is thermodynamic stability?
The position of equilibrium which is measured using the equilibrium constant
Is there a correlation between kinetic and thermodynamic stability?
No
What is used to show kinetic stability?
small k
What is used to show thermodynamic stability?
large K
What do you measure the thermodynamic affinity of?
the ligand binding to the metal
What equation is used to calculate K?
K = [Products]/[reactants]
What is the binding of the ligand like when the value of K is large?
Tight binding
What is the binding of the ligand like when the value of K is small?
Weak binding
What value of K is favoured?
Large value of K
Due to stability constants usually being large, what is the more convenient way to measure them?
Use Log10(K)
What does K not tell you anything about?
Rate There is no relationship to the rate of reaction A large K does not mean ligands bind fast
What symbol is used for the formation constant?
β
What would the general equation for K1 be?
K1 = [MLⁿ⁺] / [Mⁿ⁺][L]
What would the general equation for K2 be?
K2 = [ML₂ⁿ⁺]/[MLⁿ⁺][L]
What would the general formation constant be?
β = [ML₂ⁿ⁺]/[Mⁿ⁺][L]²
How would you generate the formation constant?
Look at the starting and end concentrations and the amount of ligands used Intermediates aren’t included
If you expand the formation constant, what can you get?
The two K constants generated β = K1 x K2
What is the general order for the values of the stability constants?
K1>K2>K3>K4
What are the three influencing factors for the value of β?
1) Sterics 2) Statistics 3) charge
Which factor is the most important?
Sterics