Orientation Selective ESEEM of Nitrogen Coordinated Oxo-Vanadium(IV) Complexes
The 14N ESEEM spectra of Oxobis(2-methylquinolin-8-olato) Vanadium(IV) (indicated as VO- (meox)2) and Oxotetra(l-methyl imidazole) Chloride Vanadium(IV) (indicated as VO(mim)4Cl+) which act as model complexes for the Vanadium containing enzyme Bromoperoxydase are analyzed in order to reveal the nitrogen coupling parameters (hyperfine and quadrupole tensors). It is demonstrated that, using orientation selective ESEEM spectra, apart from the magnitudes, also the orientations of the quadrupole and hyperfine interaction tensors can be estimated. It turns out that the orientations of the derived tensors can be related to the crystal structures of the two complexes: The maximum quadrupole component is lying in the plane of the ligand. It may therefore be concluded that for an unknown complex (such as Bromoperoxydase), the orientation of the quadrupole interaction can be used to probe the orientation of the ligand (presumably imidazole) with respect to the VO bonding axis.
- 3).E.J. Reijerse, J. Shane, E. de Boer, and D. Collison. in Electron Magnetic Resonance of Disordered Systems, N.D. Yordanov, editor, World Scientific, Singapore, 1989Google Scholar