Table 4. Hα–Fand Cα–F Internuclear Distances of the s-trans Conformations of Compounds 1a–p Calculated at mPW1PW91/6-311G(d,p), IEFPCM: CHCl3.
| internuclear
distance (10–10 m) |
||||
|---|---|---|---|---|
| compound | R1 | R2 | Hα–F | Cα–F |
| 1a | –CH(CN)2 | –H | 2.40 | 2.71 |
| 1b | –CH(CN, CO2Et) | –H | 2.43 | 2.73 |
| 1c | –CH2CH3 | –H | 2.43 | 2.76 |
| 1d | –H | –H | 2.48 | 2.74 |
| 1e | –Br | –H | 2.25 | 2.81 |
| 1f | –CH3 | –H | 2.43 | 2.76 |
| 1g | –CO2CH2CH3 | –H | 2.38 | 2.75 |
| 1h | –H | 4′-Br | 2.48 | 2.75 |
| 1i | –H | 5′-Br | 2.48 | 2.75 |
| 1j | –H | 4′-OH | 2.48 | 2.75 |
| 1k | –H | 4′-F | 2.48 | 2.75 |
| 1l | –H | 4′,5′-F | 2.49 | 2.76 |
| 1m | –H | 5′-NO2 | 2.50 | 2.76 |
| 1n | –H | 4′-OCH3 | 2.49 | 2.75 |
| 1o | –CH3 | 4′-F | 2.43 | 2.77 |
| 1p | –Cl | 4′-F | 2.30 | 2.81 |