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

Chapter 4
The Nb–O distances vary between 1.817 (2) and 2.201 (2) Å and the O–Nb–O
angles vary between 78.88 (8) and 102.78 (9) °, illustrating the significant distorted
octahedral geometry around the metal centre. All bond lengths and angles are within
normal ranges of these kinds of complexes. 18,19,20,21
Figure 4.6: The asymmetric unit of [Nb(acac-κ 2 -O,O’)(OEt)2(µ 2 -O)]4 with disorder showing
numbering scheme. Hydrogen atoms have been omitted for clarity. Displacement ellipsoids
are drawn at the 50% probability displacement level.
The [Nb(acac-κ 2 -O,O’)(OEt)2(µ 2 -O)]4 complex formed a square, cage like structure
with oxygen as bridging atoms between the Nb atoms. The O1–Nb1–O5 and the
O5–Nb2–O1 i (i = 2-x, 1-y, 1-z) bond angels are 97.12 (10) ° a nd 93.53 (10) °
respectively. The Nb1–O1, O1–Nb2, Nb1–O5 and O5–Nb2 i bond lengths are 2.020
(2) Å, 1.817 (2) Å, 1.820 (2) Å and 2.015 (2) Å respectively, therefore the Nb1 to Nb2
interatomic distance is 3.837 Å and that of the the Nb1 to Nb2 i is 3.835 Å. This makes
an almost perfect square with the 4 sides equal in length and the angles only slightly
larger than 90 °.
18 F. A. Cotton, W. J. Diebold, W. J. Roth, Inorg. Chem., 24, 3509, 1985.
19 F. A. Cotton, W. J. Diebold, W. J. Roth, Inorg. Chem., 26, 3323, 1987.
20 B. Ooi, I. Sotofte, Inorg. Chim. Acta, 357, 3780, 2004.
21 N. Steunou, C. Bonhomme, C. Sanchez, J. Vaisserman, L. G. Hubert-Pfalzgraf, Inorg. Chem., 37, 901, 1998.
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