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

2.6.3.3 [NbCl3O(ttbd) - ]
Chapter 2
An article of a 6-coordinated niobium complex, with 1,1,1-trifluoro-4-thenoyl-
2,4-butanedionato (ttbd) as bidentate ligand, was published by Daran et al. 63
in 1979. The crystal structure was determined by single crystal X-ray analysis
and was found to be built up of isolated ammonium cations and trichlorooxo-
(1,1,1-trifluoro-4-thenoyl-2,4-butanedionato)niobate(V) anions. The niobium
atom was at the centre of a distorted coordination octahedron of three
chlorido atoms, the chelating diketone and the oxido atom. The niobium-
oxygen bond was determined as 1.704 Å and a bond order of two was
suggested by Wendling and Röhmer. 64 The average Nb-O(ttbd) bond length
with regards to the β-diketone was determined as 2.17 Å.
2.6.3.4 trans-[NbCl2(OEt)2(dbm)]
Figure 2.8: Structure of [NbCl3O(ttbd) - ].
Antiñolo et al. 65 published an article on the reactivity of alkoxo-niobium(V)
compounds towards O,O’-chelate ligands in 2000. The aim of their work was
to investigate the synthesis and structural characterisation of trans-
[NbCl2(OEt)2(dbm)]. The niobium complex crystallized in the monoclinic
spacegroup P21/n, with one molecule in the asymmetric unit cell. The product
was described as a pseudooctahedral Nb(V) complex containing two trans-
chloride ligands in the axial positions and two cis-ethoxide ligands and a β-
63 J. Daran, Y. Jeannin, J. E. Guerchais, R. Kergoat, Inorg. Chim. Acta., 33, 81, 1979.
64 E. Wendling, R. Röhmer, Bull. Soc. Chim. Fr., 1, 8, 1967.
65 A. Antiñolo, F. Carrillo-Hermosilla, J. Fernández-Baeza, S. Garcia-Yuste, A. Otero, E. Palomares, A. M.
Rodriguez, L. F. Sánchez-Barba, J. Organomet. Chem., 603, 194, 2000.
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