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

Chapter 4
Table 4.2: Selected bond lengths for [NbCl(acac-κ 2 -O,O’)(OMe)3].
Atoms Bond length (Å) Atoms Bond length (Å)
Nb – O1 2.109 (2) O1 – C1 1.282 (3)
Nb – O2 2.085 (2) O2 – C3 1.289 (3)
Nb – O3 1.879 (3) O3 – C6 1.416 (3)
Nb – O4 1.864 (1) O4 – C7 1.414 (3)
Nb – O5 1.862 (2) O5 – C8 1.419 (2)
Nb – Cl1 2.470 (1) C1 – C2 1.397 (3)
Table 4.3: Selected bond angles for [NbCl(acac-κ 2 -O,O’)(OMe)3].
Atoms Bond angles (°) Atoms Bond angles (°)
O1 – Nb – O2 80.74 (6) O4 – Nb – Cl1 88.76 (5)
O1 – Nb – O4 170.09 (6) O1 – Nb – Cl1 84.06 (5)
O2 – Nb – O5 163.63 (6) C1 – C2 – C3 123.71 (2)
O2 – Nb – O3 88.43 (7) Nb – O1 – C1 133.52 (17)
O3 – Nb – O4 99.45 (7) Nb – O2 – C3 133.86 (17)
O4 – Nb – O5 100.76 (9) Nb – O3 – C6 141.75 (16)
O3 – Nb – Cl1 167.55 (6) Nb – O5 – C8 144.13 (16)
A distorted octahedral geometry is displayed by [NbCl(acac-κ 2 -O,O’)(OMe)3], with
Nb–O distances in the range of 1.862 (2) – 2.109 (2) Å and the Nb–Cl distance of
2.470 (1) Å. The O–Nb–O angles vary between 80.74 (6) and 170.09 (6) °, while the
trans Cl– Nb–O angle is 167.55 (6)°. All the bond distan ces and angles are similar to
other relevant niobium(V) structures. 9,10,11,12
Enolate type delocalization behaviour is found in the acac bidentate ring. The O1–C1
and O2–C3 bond distances are of similar order (1.282 (3) and 1.289 (3) Å), but are
longer than the average C=O bond distance of 1.22 Å and shorter than a single C–O
bond distance of 1.43 Å. The three carbon atoms in the acac backbone also have
9
M. Sokolov, A. L. Gushchin, S. V. Tkachev, D. Y. Naumov, P. Nunez, P. Gili, J. G. Platas, V. P. Fedin. Inorg. Chim.
Acta, 358, 2371, 2005.
10
M. Sokolov, H. Imoto, T. Saito, V. Fedorov, J. Chem. Soc. Dalton Trans., 85, 1999.
11
A. Antinolo, F. Carrillo-Hermosilla, J. Fernandez-Baeza, A. Otero, E. Palomares, A. M. Rodriguez, L. F. Sanchez-
Barba, J. Organomet. Chem., 603, 194, 2000.
12
F. Dahan, R. Kergoat, M. C. Senechal-Tocquer, J. E. Guerchais, J. Chem. Soc. Dalton Trans., 2202, 1976.
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