Synthetic and structural studies of monocyclopentadienyl cyclometalated aryl tantalum(V) compounds

• Published in: Dalton transactions : an international journal of inorganic chemistry 2011-01, Vol.40 (33), p.8399-8406
• Main Authors: Galajov, Miguel, Galindo, Agustín, García, Carlos, Gómez, Manuel, Gómez-Sal, Pilar, Parra, Andrés
• Format: Article
• Language: English
• Subjects: Aromatic compounds; Diffraction; Equivalence; Hydrogen atoms; Ligands; Molecular structure; NMR spectroscopy; X-rays
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c1dt10223k

Cyclometalated aryl tetra- or trichlorido cyclopentadienyl tantalum complexes [TaXCl(3){C(6)H(4)(2-CH(2)NMe(2))-κ(2)C,N}] (X = Cl 1, η(5)-C(5)H(5)2, η(5)-C(5)H(4)(SiMe(3)) 3, η(5)-C(5)Me(5)4) containing a five-membered TaC(3)N chelate ring were synthesized by reaction of the TaXCl(4) (X = Cl, η(5)-C(5)H(5), η(5)-C(5)H(4)(SiMe(3)), η(5)-C(5)Me(5)) with the appropriate lithium aryl reagent [Li{C(6)H(4)(2-CH(2)NMe(2))}]. The reported complexes were studied by IR and NMR spectroscopy and the X-ray molecular structures of compounds 2, 3 and 4 were determined by diffraction methods. These compounds were theoretically analyzed by the DFT method and their structures were rationalized. The preferential coordination of the 2-{(dimethylamino)methyl}phenyl ligand was justified by an analysis of the molecular orbitals of the Ta(η(5)-C(5)H(5))Cl(3) and C(6)H(4)(2-CH(2)NMe(2)) fragments. In addition, the exchange pathways that account for the NMR equivalency of the Me(2)N- methyl groups and -CH(2)- hydrogen atoms of the coordinated C(6)H(4)(2-CH(2)NMe(2))-κ(2)C,N ligand were theoretically studied.