Table 2. Thermodynamic Parameters for the Equilibrium between S = 0 and S = 2 Spin States in THF-d8 Solution for Compounds 1–6.
| 1a | 1 | 2 | 3 | 4 | 5 | 6 | |
|---|---|---|---|---|---|---|---|
| ΔH (kJ mol–1) | 22.2 ± 0.3 | 18.8 ± 0.1 | 27.2 ± 0.5 | 8.6 ± 0.2 | 17.4 ± 0.2 | 20.6 ± 0.2 | 17.9 ± 0.1 |
| ΔS (J mol–1 K–1) | 64 ± 1 | 54 ± 1 | 75 ± 2 | 29 ± 1 | 50 ± 1 | 56 ± 1 | 54 ± 1 |
| T1/2b (K) | 345 ± 7 | 346 ± 3 | 361 ± 12 | 300 ± 15 | 345 ± 13 | 368 ± 5 | 329 ± 4 |
a
Data reproduced from ref (14), measured in toluene-d8.
b
The uncertainty in T1/2 is obtained by using error propagation from ΔH and ΔS.