Stabilita kationt˚u – afinita k hydridov´emu aniontu
R + H R H ∆H
CH3
CH3CH2
CH3CH2CH2
H3C C CH3
CH3
H3C C CH3
H
H2N CH2
HO CH2
H2C CH CH2
H2C CH
CH2
∆H (kJ/mol) ∆H (kJ/mol)
−312
−273
−266
−246
−231
−218
−243
−256
−287
−234
Efekt sterick´e z´abrany na rychlost SN2
R + Nu R Nu
k
H2O
X + X
k/k0
1
0,33
0,013
0,0008
0,00000013
1,3
4,0
H3C
CH3CH2
CH3CH2CH2
CH
H3C
H3C
CHCH2CH2
H3C
H3C
H2C CH CH2
CH2
k/k0
1
Nukleofilita vs bazicita
R + Nu R Nu
pKa
−10
0,0
+4,8
+10
k
H2O
X + X
k/k0
ClO4
H2O
H3C C
O
O
O
HO
S
I
Br
Cl
F
+14,0
0,0
1,0
900
2.000
12.000
+10O 2.000
+6,4 50.000.000
pKa
−10
−9
−7
k/k0
120.000
5.000
1.100
+3 0,0
2