Related Experiment Video
Updated: Aug 13, 2026
Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups
Published on: February 11, 2012
Structural Distortions in Six-Coordinate Adducts of Niobium(V) and Tantalum(V)
Janet R. Clark1, April L. Pulvirenti, Phillip E. Fanwick
1Department of Chemistry, 1393 Brown Building, Purdue University, West Lafayette, Indiana 47907-1393, Laboratory for Applied Quantum Chemistry, University of Thessaloniki, Thessaloniki, Greece, and Laboratoire de Chimie-Théorique, Bâtiment 490, Université de Paris-Sud, 91405 Orsay, France.
Abstract:
The mixed chloro-aryloxide compounds [M(OC(6)H(3)Pr(i)(2)-2,6)(2)Cl(3)](2) (M = Nb (1a), Ta (1b); both structurally characterized) and [M(OC(6)H(3)Pr(i)(2)-2,6)(3)Cl(2)] (M = Nb (2a), Ta (2b)) react with pyridine (py) and PMe(2)Ph to produce a series of adducts cis-mer-[MCl(3)(OC(6)H(3)Pr(i)(2)-2,6)(2)(L)] (M, L: Nb, py (3a); Ta, py (3b); Nb, PMe(2)Ph (4a); Ta, PMe(2)Ph (4b)) and trans-mer-[MCl(2)(OC(6)H(3)Pr(i)(2)-2,6)(3)(L)] (M, L: Nb, py (5); Nb, PMe(2)Ph (6a); Ta, PMe(2)Ph (6b)). The assigned geometric arrangement of ligands is based upon (1)H NMR studies and single-crystal X-ray diffraction analyses of 3a, 3b, 4, 6a, and 6b. The salt complex [HPMe(2)Ph](+)[mer-NbCl(3)(OC(6)H(3)Pr(i)(2)-2,6)(3)](-) (7) has also been isolated and structurally characterized. The structural parameters for the neutral adducts are compared with those of previously reported hydrido aryloxides of tantalum. A small but consistent distortion away from octahedral geometry involving the bending of mutually trans anionic ligands toward the neutral donor group is observed. Theoretical analysis at several levels of theory (RHF, MP2, and DFT) on model compounds [Ta(OH)(2)(H)(2)(PH(3))(X)] (X = Cl, OH, H) show a distortion involving bending of the trans-hydride groups toward the PH(3) ligand for X = Cl and OH. This distortion can be accounted for in terms of an improvement in both X p to metal d pi-bonding and Ta-H sigma-bonding. The contribution of sigma-bonding effects is clearly shown in the case of X = H, where again a bend of the two hydride ligands toward the Ta-P bond is calculated. A smaller distortion of the Cl ligands in trans-mer-[Ta(OH)(3)(Cl)(2)(PH(3))] is also predicted.
More Related Videos
08:13Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area
Published on: February 19, 2018
09:06Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
Related Concept Videos
02:57Coordination Number and Geometry
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
02:42Valence Bond Theory
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
01:26Imperfections in Crystal Structure: Stoichiometric Point Defects
01:29Imperfections in Crystal Structure: Non-Stoichiometric Defects