Table 1.
Ab initio calculation of the separation of glycosidic oxygen atoms during chair inversion in galactouronic acid
| Method |
4C1
|
Boat*
|
1C4
|
4C1 → boat
|
Boat → 1C4
|
4C1 → 1C4
|
|---|---|---|---|---|---|---|
| l1, Å | l2, Å | l3, Å | (l2 − l1)/l1, % | (l3 − l2)/l2, % | (l3 − l1)/l1, % | |
| HF/6-31G* | 4.462 | 5.044 | 5.435 | 13.0 | 7.8 | 21.8 |
| B3LYP/6-31G* | 4.522 | 4.891 | 5.492 | 8.2 | 12.3 | 21.5 |
| AFM data | 4.500 | 4.901 | 5.405 | 8.9 ± 0.8† | 10.3 ± 0.7† | 20.1 ± 0.9† |
*
This is a symmetrical boat with the “flagpole” hydroxyl at positon C2 and the “flagpole” hydrogen at position C5 (not shown).
†
Standard error of the mean (n = 8).