Nucleophiles and L.G. Flashcards
Do stronger or weaker bases make a better L.G.?
Weaker bases.
When basicity decreases does the L.G. ability increase or decrease?
L.G. ability increases.
Good L.G. have what type of conjugate acids?
Strong conjugate acids. (Low Pka values)
Equil. favors products when the L.G. or the Nu. is a weaker base?
When the L.G. is a weaker base than the Nu.
Name two possible traits of a Nu.
A Nu. either has a pi bond or a lone pair.
What do Nu.’s attack?
They attack e- deficient atoms.
Is the stronger or weaker base a better Nu.?
The stronger base.
A strong, negative Nu. has what type of conjugate acid?
A weak conjugate acid. (A high Pka)
In what direction across a row of the P.T. does basicity increase?
Up a column and right-to-left.
When does nucleophilicity NOT parallel basicity?
When steric hinderance becomes important.
What do we call a sterically hindered base? (Poor Nu.)
A nonnucleophilic base.
What is a polar protic solvent?
A solvent containing molecules with a polarized H atom (H + N or O)
What is a polar aprotic solvent?
A solvent containing molecules with no polarized H atoms. (Still may have a net dipole)
In polar protic solvents, nucleophilicity increases in what direction on the P.T.?
Nucleophilicity increases DOWN a column of the P.T. (Oppos. of basicity)
