Table 2.
Optimized structures, sums of electronic and thermal enthalpies (H298, a.u.) of the studied compounds, dihedral angles (φ, °) of the dimers and bond dissociation enthalpies (BDE, kcal·mol−1). The values calculated for the structures optimized in water are given in parentheses.
| compound | molecule | radical | biradical | BDE, kcal·mol−1 |
| 2 |
 H298 = −651.868596 (−651.878465) |
 H298 = −651.241585 (−651.255413) |
— | 79.53 (77.04) |
| 6 |
 H298 = −1302.554462 (−1302.573379) φ = 64.576 (68.112) |
 H298 = −1301.928383 (−1301.950845) φ = 63.311 (64.932) |
 H298 = −1301.301389 (−1301.328123) φ = 68.849 (67.146) |
(r) 78.94 (76.71) (br) 79.52 (76.83) |
| 3 |
 H298 = −653.066142 (−653.075843) |
 H298 = −652.438022 (−652.453157) |
— | 80.23 (76.81) |
| 7 |
 H298 = −1304.948860 (−1304.968218) φ = 62.231 (68.021) |
 H298 = −1304.321729 (−1304.346187) φ = 59.741 (64.752) |
 H298 = −1303.693274 (−1303.724652 φ = 69.640 (67.224) |
(r) 79.60 (76.40) (br) 80.44 (76.09) |
| 4 |
 H298 = −1032.317386 (−1032.405066) |
 H298 = −1031.689944 (−1031.705790) |
— | 79.80 (77.56) |
| 8 |
 H298 = −2063.452015 (−2063.475877) φ = 63.073 (66.675) |
 H298 = −2062.825553 (−2062.852556) φ = 61.652 (64.879) |
 H298 = −2062.198378 (−2062.228955) φ = 66.802 (65.673) |
(r) 79.18 (77.21) (br) 79.63 (77.38) |
| 5 |
 H298 = −687.821096 (−687.831734) |
 H298 = −687.193195 (−687.207615) |
— | 80.09 (77.71) |
| 9 |
 H298 = −1374.461690 (−1374.481055) φ = 64.582 (67.996) |
 H298 = −1373.834836 (−1373.857451) φ = 62.755 (66.047) |
 H298 = −1373.207082 (−1373.233750) φ = 67.994 (66.845) |
(r) 79.43 (77.39) (br) 80.00 (77.45) |
| 1 (enol) |
 H298 = −1263.272328 (−1263.286825) |
 H298 = −1262.646509 (−1262.664892) |
 H298 = −1262.019583 (−1262.041985) |
(r) 78.78 (br) 79.48 |
| 11 |
 H298 = −1285.030320 |
 H298 = −1284.417253 |
70.78 | |
| 10 |
 (H298 = −845.002438) |
 (H298 = −844.389866) |
(70.46) | |
| 13 |
 H298 = −1145.250604 (−1145.270685) |
 H298 = −1144.625264 (−1144.643325) |
78.48 (79.74) |
|