About the database
The database contains a compilation of the published reactivity parameters E, N, and sN which allow to calculate the rate constants for combination reactions of electrophiles with nucleophiles by Equation (1) :
log k20°C = sN(N + E) (1)
E = electrophilicity parameter
N = nucleophilicity parameter (solvent dependent)
sN = nucleophile-specific sensitivity parameter (solvent dependent)
Be aware of the fact, that the three-parameter Equation (1) does not include steric effects and, therefore, can only be used for semiquantitative predictions of rate constants. While rate constants k for the reactions with reference electrophiles are usually reproduced with deviations of less than a factor of 2, deviations by a factor of 10 to 100 have to be expected, when both reaction partners are not from the reference sets.
This is quite helpful in view of the fact that Equation (1) presently covers a reactivity range of 40 orders of magnitude.
As carbon-centered electrophiles and carbon-centered nucleophiles have been used for the parameterization, Equation (1) is only applicable when one or both reaction centers are carbon.
Do not use the reactivity parameters for predicting reactions with bulky reagents (for exceptions see entries for tritylium ions)
The electrophiles and nucleophiles in the database are classified by stars.
- 5 stars: reference electrophile/nucleophile
- 4 stars: quasi-reference electrophile/nucleophile
- 3 stars: 3 or more reference electrophiles/nucleophiles have been used for the determination of the reactivity parameter(s)
- 2 stars: only 2 reference electrophiles/nucleophiles have been used for the determination of the reactivity parameter E or N (with reasonable sN)
- 1 star: only 1 reference electrophile/nucleophile has been used for the determination of the reactivity parameter E or N (sN was estimated)