Tautomer energy comparison
using model chemistry: mPW1PW91/6-31G**
| formula |
sketch |
Energy (kJ mol-1) |
Name |
difference |
| A |
B |
calculated |
experiment |
A |
B |
| C3H4 |
 |
 |
-11 |
7 |
allene |
propyne |
-18 |
| C4H6 |
 |
 |
40 |
51 |
1,2-Butadiene |
1,3-Butadiene |
-11 |
| C4H6 |
 |
 |
-24 |
-3 |
1,2-Butadiene |
1-Butyne |
-21 |
| C4H6 |
 |
 |
9 |
17 |
1,2-Butadiene |
2-Butyne |
-8 |
| C4H6 |
 |
 |
32 |
49 |
Cyclobutene |
1,3-Butadiene |
-17 |
| C4H6 |
 |
 |
67 |
82 |
1-Methylcyclopropene |
1,2-Butadiene |
-16 |
| C4H6 |
 |
 |
-47 |
-42 |
Methylenecyclopropane |
1-Methylcyclopropene |
-5 |
| C3H6O |
 |
 |
101 |
110 |
Oxetane |
Propanal |
-9 |
| C4H8 |
 |
 |
12 |
33 |
cyclobutane |
1-Butene |
-21 |
| C3H4O2 |
 |
 |
-18 |
-29 |
2-Propenoic acid |
β–Propiolactone |
10 |
| C4H6S |
 |
 |
0 |
-4 |
Thiophene, 2,5-dihydro- |
Thiophene, 2,3-dihydro- |
4 |
| C5H8 |
 |
 |
-33 |
-25 |
1,3-Pentadiene, (E)- |
1,4-Pentadiene |
-7 |
| C5H8 |
 |
 |
-58 |
-64 |
1,3-Pentadiene, (E)- |
1,2-Pentadiene |
6 |
| C5H8 |
 |
 |
40 |
52 |
1,2-Butadiene, 3-methyl- |
1,3-Butadiene, 2-methyl- |
-12 |
| C4H8O |
 |
 |
-21 |
-29 |
Butanal |
Furan, tetrahydro- |
8 |
| C5H10 |
 |
 |
13 |
5 |
1-Butene, 2-methyl- |
2-Butene, 2-methyl- |
7 |
| C6H8 |
 |
 |
-0 |
3 |
1,4-Cyclohexadiene |
1,3-Cyclohexadiene |
-3 |