Synthesis, solution and crystal structures of dinuclear vanadium(V) oxo monoperoxo complexes with mandelic acid: (NR4)2[V2O2(O2)2(mand)2] . xH2O [R=H, Me, Et; MAND=mandelato(2-)=C8H6O3 2-]
| Authors | |
|---|---|
| Year of publication | 2004 |
| Type | Article in Periodical |
| Magazine / Source | Polyhedron |
| MU Faculty or unit | |
| Citation | |
| Field | Inorganic chemistry |
| Keywords | Crystal structure; IR spectra; 51V NMR spectra;Vanadium(V) peroxo mandelato complex; |
| Description | Vanadium(V) oxo peroxo mandelato complexes were prepared from aqueous solution and characterized by elemental analysis, IR, UV-Vis and 51V NMR spectroscopies. The single crystal X-ray studies of (NMe4)2[V2O2 (O2)2(R,S-mand)2].6.5H2O (3), (NMe4)(NH4)[V2O2(O2)2(R,S-mand)2].2H2O (4) and (NEt4)2[V2O2(O2)2(R-mand)2] (8) revealed that the mandelato ligand behaves as a bidentate chelator adopting the (O-, COO-) donor set. The complex anions in structures of 3 and 8 contain a dinuclear V2O2 core with cyclic arrangement of two vanadium atoms and two hydroxyl oxygen atoms from the bridging mand ligands. Each vanadium atom is coordinated by six oxygen atoms arising from two hydroxyl and one carboxyl groups, 2-peroxo ligand and one end-bonded oxo ligand. The coordination polyhedron can be described as distorted pentagonal pyramid. The structure of 4 is unique as it contains in the unit cell differently coordinated water molecules in two types of dinuclear anions: [V2O2(O2)2(R-mand)2(H2O)]2-, with nearly symmetrically bonded bridging water molecule and pentagonal bipyramidal arrangement arround both vanadium atoms, and [V2O2(O2)2(S-mand)2(H2O)]2-, with the water molecule coordinated only to one vanadium atom. The vanadium atoms thus have different coordination geometries: pentagonal pyramidal and pentagonal bipyramidal, the latter exhibiting a better planarity of the fitted atoms of the pentagonal plane and a smaller deviation of the vanadium atom from this plane. |
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