DFT Calculations of ⁵¹V Solid-State NMR Parameters of Vanadium(V) Model Complexes

Two cis-dioxovanadium(V) complexes and three monooxovanadium(V) complexes with different coordination numbers and ligand spheres, serving as model complexes for vanadium haloperoxidases, were studied by ⁵¹V solid-state NMR spectroscopy. The most important ⁵¹V solidstate NMR parameters (quadrupolar coupling constant CQ, asymmetry of the EFG tensor ηQ, isotropic chemical shift δiso, chemical shift anisotropy δσ, asymmetry of the CSA tensor ησ and the Euler angles α, β and γ) describing the quadrupolar and chemical shift anisotropy interactions were determined theoretically with DFT methods employing the B3LYP functional and experimentally using genetic fitting algorithms. Calculations of δiso values were treated with different referencing values of VOCl₃ computed with different-sized basis sets using the "counterpoise method". The calculated CQ values were discussed in terms of the quadrupolar moment Q. Absolute tensor orientations of CSA and EFG tensors were computed by DFT. These orientations were found to correlate to structural features of the model complexes.