Table 2. NMR Shifts for Compounds 1a (S = 3/2) and 2a (S = 1/2) Calculated Using PBE0/TZ2P In Vacuo or in a Supramolecular Clusterc.
| atom | vacuoa | vacuob | clust(3) | clust(3↑↓)d | Δ↑↓ | clust(9) | clust(9) + Δ↑↓ | exp | |
|---|---|---|---|---|---|---|---|---|---|
| 1a | C1 | +1337 | +1304 | +1291 | +1286 | +1155 | |||
| C2 | +248 | +254 | +268 | +266 | +316 | ||||
| C3 | –569 | –567 | –551 | –531 | –421 | ||||
| 2a | C1 | +137 | +107 | +86 | +86 | +0 | +83 | +83 | +96 |
| C2 | –17 | –25 | –32 | –57 | –25 | –39 | –64 | –67 | |
| C3 | +1167 | +1168 | +1092 | +988 | –104 | +1059 | +955 | +929 |
c
The geometry of the central molecule was optimized in the supramolecular cluster unless stated otherwise; see Section 4.
a
Geometry optimized in vacuo (EPR and NMR parameters calculated in vacuo using ADF2017).
b
Geometry optimized in clust(9) (EPR and NMR parameters calculated in vacuo using ADF2019 and ADF2017, respectively); clust(3): two cluster neighbors are diamagnetic (with Ca atoms).
d
clust(3↑↓): all three molecules are open shell (see Table 3); Δ↑↓: calculated as clust(3↑↓) – clust(3); clust(9): eight cluster neighbors are diamagnetic (with Ga and Ca atoms for 1a and 2a, respectively); for Cartesian coordinates, see the Supporting Information; exp: experimental solid-state NMR data.