A solution and solid state study of niobium complexes University of ...

Chapter 4
Table 4.5: Selected bond lengths for [Nb(acac-κ 2 -O,O’)(OEt)2(µ 2 -O)]4.
Atoms Bond length (Å) Atom Bond length (Å)
Nb1 – O1 2.020 (2) Nb2 – O1 1.817 (2)
Nb1 – O2 2.197 (2) Nb2 – O7 2.091 (3)
Nb1 – O3 2.088 (2) Nb2 – O8 2.201 (3)
Nb1 – O4 1.894 (1) Nb2 – O9 1.880 (3)
Nb1 – O5 1.820 (2) Nb2 – O10 1.893 (2)
Nb1 – O6 1.879 (2) Nb2 i – O5 2.015 (3)
[i = 2-x, 1-y, 1-z]
Table 4.6: Selected bond angles for [Nb(acac-κ 2 -O,O’)(OEt)2(µ 2 -O)]4.
Atoms Bond angles (°) Atoms Bond angles (°)
Nb1 – O1 – Nb2 170.22 (13) O1 – Nb2 – O5 i
Nb1 – O5 – Nb2 i
177.27 (13) O10 – Nb2 – O5 i
70
93.53 (10)
163.11 (12)
O5 – Nb1 – O1 97.12 (10) O9 – Nb2 – O7 162.89 (11)
O4 – Nb1 – O1 161.84 (10) O1 – Nb2 – O8 169.62 (10)
O6 – Nb1 – O3 163.66 (10) O7 – Nb2 – O8 79.04 (11)
O5 – Nb1 – O2 171.85 (10) C1 – O2 – Nb1 129.84 (19)
O3 – Nb1 – O2 80.03 (10) C10 – O7 – Nb2 133.40 (16)
[i = 2-x, 1-y, 1-z]
The crystal structure displays a 55:45 positional disorder at one of the ethoxy
groups, C17 and C18, as well as a 72:28 positional disorder at C9. There is no
hydrogen interaction or π-π stacking observed in the crystal structure. The
molecules pack in a sheet-like arrangement, forming channels when viewed in the
direction of the a-axis (Figure 4.10).