Electronic Structure of Bis(2,4-pentanedionato-O,O‘)oxovanadium(IV). A Photoelectron Spectroscopy, Electronic Spectroscopy, and ab Initio Molecular Orbital Study

Abstract

The electronic structure of the title VO(acac)(2) complex has been investigated using effective core potential configuration interaction ab initio calculations, UV-photoelectron spectroscopy, and electronic spectroscopy. The metal-ligand bonding with the equatorial acac(-) ligands is dominated by sigma interactions involving the filled ligand orbitals and the empty orbitals of the d(1) vanadium(IV) ion. The oxovanadium interactions involve a larger metal-d participation thus resulting in a strong V-O bonding having partial triple-bond character. Additional three-orbital-four-electron stabilizing interactions involving the filled acac(-) MOs and the oxovanadium orbitals further reinforce both the axial and equatorial bonds. The unpaired metal-d electron is completely localized in the nonbonding d(x)()()2(-)(y)()()2 orbital. The low ionization energy of the photoelectron spectrum has been fully assigned on the basis of combined DeltaSCF and configuration interaction calculations. The same theoretical approach has, in addition, provided a good fitting of frequencies associated with "d-d" and charge transfer electronic transitions.

Unveiling phonons in a molecular qubit with four-dimensional inelastic neutron scattering and density functional theory

“…The double bond of the vanadyl VO 2þ ion is much shorter than single V-O bonds, leading to a strong axial distortion of the ligand field acting on the metal centre. (It should be highlighted that, despite the VO 2+ unit is commonly described by a double bond, a triple bond has also been proposed 42,43 and supported by theoretical calculations 44 . The resulting splitting of the V IV d-orbitals yields a d xy orbital lying the lowest in energy, singly occupied and well separated from the other orbitals.…”

“…This also quenches the orbital contribution to the ground state, making these S ¼ 1=2 systems ideal candidates as molecular spin qubits. The large splitting between the ground state doublet and the first excited levels also ensures that no magnetic excitations are present in the energy range up to more than 1500 meV 44 . Recent studies on this family of compounds suggest that the rigidity of the VO moiety is also at the basis of their long quantum coherence times up to room temperature 14,30,45 .…”

Magnetic property and crystal structure of bis [N-(4-chlorophenyl) salicylideneaminato] oxovanadium (IV)

“…While the unpaired electron is essentially localized in the vanadium 3d xy orbital [45][46][47], the significant spin polarization of the other d orbitals is observed as a result of 3d atomic orbital spin population analysis ( Table 2). The isotropic spin polarization of 2p orbitals for axial oxygen atoms is also observed.…”

SOMC grafting of vanadium oxytriisopropoxide (VO(OiPr)3) on dehydroxylated silica; analysis of surface complexes and thermal restructuring mechanism

“…7. In 2m the V-O bond is calculated to be approximately 1.58Å long suggesting a partial triple bond character 42,43 as demonstrated by the NBO analysis (see Fig. S5 † for an overview).…”