L1 alkali metals organometallics Flashcards
What type of donors do hard M+ cations favour?
Hard donors (O,N)
Are the M+ cations of light elements hard or soft?
Very hard and polarising
eg. Li+, Na+
What is the bonding like for M+ cations?
Essentially ionic
What are M-L interactions like for M+ ions?
Quite weak
The complexes are labile and have rapid ligand exchange
What is the lability like as you move down group 1 M+?
Increases
What is the bonding like in R-M complexes?
Essentially ionic
How does ionic character change down a group?
It increases down the group
How does electropositive character change down a group?
Increases
How does ionic character change with s-character of the carbon atom?
Ionic character increases with increased s-character
What is aggregation?
Formation of M+ ion clusters
Why is aggregation common?
It allows for higher coordination number of M+ to be achieved
What factors affect aggregation?
M+ size Steric demands of R- Solvation + presence of donors Temp Concentration Solvent
How does M+ size affect aggregation?
Larger M+ require higher coordination number and have a greater tendency to aggregate
How do the steric demands of R- affect aggregation?
Larger R- blocks coordination sites which lower the aggregation state
What is the effect of solvation on aggregation?
There is competition between aggregation and solvation (presence of donors)
Donors disfavour aggregation
