mechanistic organic Flashcards
what is a transition state
species does not exist as a stable entity.
the least stable between two species
what is a intermediate
species can exist for some some length of time
what is the rate-limiting step
the step with the highest energy transition state
the highest energy point of free energy between SM and P
what is Hammond postulate
if energy of the TS leading to or from a species is similar to that species, then both structures are expected to be similar
what is Curtin-hammett
the product distribution doesnt reflect the distribution of the SM
what info do we get from entropy
entropy relates to the change of entropy going from SM to TS
-when more negative, loss of entropy
- +50 to -10 unimolecular
- -50 bimolecular
- -40 to -120 bimolecular
- -120 and less bimolecular with constraints
for Sn2 reactions what is the rate law
K[RX][Nu-]
Sn1 rate law
K[RX]
what does -1 slope at ph<2 mean
the rate is dependent on[H+]
what does a flat line mean in a pH profile
ph is independent of the rate
what does +1 slope at pH>6 mean
the rate is dependent on [OH-]
things to do if you suspect an intermediate
-characterise it
- try and isolate it
- trap it
- generate independently
