pre-association

https://doi.org/10.1351/goldbook.P04794
A step on the
reaction path
of some
stepwise reactions
in which the
molecular entity
C is already present in an
encounter pair
or
encounter complex
with A during the formation of B from A, e.g.
In this mechanism the
chemical species
C may but does not necessarily assist the formation of B from A, which may itself be a
bimolecular
reaction with some other
reagent
. Pre-
association
is important when B is too short-lived to permit B and C to come together by
diffusion
.
See also:
microscopic diffusion control
,
spectator mechanism
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1152 [Terms] [Paper]