Croatica Chemica Acta (Dec 2015)

Computational Study on Mössbauer Isomer Shifts of Some Organic-neptunium (IV) Complexes

  • Masashi Kaneko,
  • Sunao Miyashita,
  • Satoru Nakashima

DOI
https://doi.org/10.5562/cca2746
Journal volume & issue
Vol. 88, no. 4
pp. 347 – 353

Abstract

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Relativistic DFT calculations are applied to some organo-neptunium (IV) complexes, Cp3NpIVX (Cp = η5-C5H5; X = BH4, Cl, OtBu, Ph, nBu), in order to understand their bonding properties between Np and the ligands. We employ scalar-relativistic ZORA Hamiltonian with all-electron basis set (SARC). The calculated electron densities at Np nucleus position in the complexes at B2PLYP / SARC theory strongly correlate to the experimental Mössbauer isomer shifts of 237Np system. The result of bond overlap population analysis indicates that the bonding strength decreases in order of X = BH4, Cl, OtBu, Ph and nBu. The tendency depends on the degree of the covalent interaction between Np 5f-electron and X ligand. It is suggested that it is important to estimate the bonding contribution of 5f-orbital to understand the electronic state for organo-actinide complexes.