Table 5. Calculated structural and thermodynamic data (kcal mol–1) for the putative amido dimers [E{N(SiMe3)2}2]2.
| [Ge{N(SiMe3)2}2]2 |
[Sn{N(SiMe3)2}2]2 |
[Pb{N(SiMe3)2}2]2 |
|||||||
| B3PW91 | B3PW91-D3 | B97-D3 | B3PW91 | B3PW91-D3 | B97-D3 | B3PW91 | B3PW91-D3 | B97-D3 | |
| E–E (Å) | 5.841 | 3.798 | 3.902 | 4.548 | 3.514 | 3.589 | 11.242 | 3.714 | 3.771 |
| E–N (Å) | 1.899 (avg.) | 1.886 (avg.) | 1.915 (avg.) | 2.119 (avg.) | 2.113 (avg.) | 2.136 (avg.) | 2.260 (avg.) | 2.241 (avg.) | 2.252 (avg.) |
| N–E–N (°) | 107.8 (avg.) | 103.9 (avg.) | 104.9 (avg.) | 105.5 (avg.) | 103.1 (avg.) | 102.7 (avg.) | 105.5 (avg.) | 101.9 (avg.) | 102.3 (avg.) |
| [E{N(SiMe 3 ) 2 } 2 ] 2 → 2 E{N(SiMe 3 ) 2 } 2 | |||||||||
| ΔE a | –5.0 | 8.4 (5.1) | 7.9 | –3.5 | 19.8 (15.6) | 16.4 | –4.1 | 15.6 (3.9) | 12.5 |
| ΔE b | –7.0 | 3.6 | –7.4 | 11.7 | –4.8 | 11.8 | |||
| ΔH c | –7.6 | 3.8 | –8.0 | 11.6 | –5.6 | 11.5 | |||
| –TΔS c | –8.8 | –16.0 | –10.0 | –15.3 | –5.2 | –15.1 | |||
| ΔG c | –16.4 | –12.2 | –18.0 | –3.7 | –10.8 | –3.6 | |||
aDissociation energy (kcal mol–1). MP2 values are in parentheses.
bWith ZPE and BSSE corrections.
cAt 25 °C (298 K) and 1 atm.