Table 1.
A comparison of the Δδαβ values for compounds 1–4, 6–11.
| Compound | Δδαβ | |
|---|---|---|
| (BDI)Nb(NtBu)Cl2py | 1 | 39.9 |
| (BDI)Nb(NtBu)F2py | 2 | 36.5 |
| (BDI)Nb(NtBu)Cl2 | 3 | 44.0 |
| (BDI)Nb(NtBu)F2 | 4 | 40.1 |
| (BDI)Nb(NtBu)Me2 | 6 | 35.2a, 35.0b |
| (BDI)Nb(NtBu)Cl(p-tol) | 7 | 39.0 |
| (BDI)Nb(NtBu)Me(p-tol) | 8 | 35.8 |
| (BDI)Nb(NtBu)2py | 9 | 30.2c, 31.7d |
| (BDI)Nb(NtBu)2(dmap) | 10 | 29.7c, 30.9d |
| (BDI)Nb(NtBu)2 | 11 | 31.3 |
a
Δδαβ in THF-d8 at 213 K.
b
Δδαβ in toluene-d8 at 213 K.
c
For the apical imido group, as determined by 1JCH and 2JCH NMR 1H–13C correlation experiments (see experimental section).
d
For the basal imido, determined as for c.