TY - JOUR
T1 - The performance of density functional theory for the description of ground and excited state properties of inorganic and organometallic uranium compounds
AU - Reta, Daniel
AU - Ortu, Fabrizio
AU - Randall, Simon
AU - Mills, David P.
AU - Chilton, Nicholas F.
AU - Winpenny, Richard E.P.
AU - Natrajan, Louise
AU - Edwards, Bryan
AU - Kaltsoyannis, Nikolas
PY - 2018/2/1
Y1 - 2018/2/1
N2 - Molecular uranium complexes are the most widely studied in actinide chemistry, and make a significant and growing contribution to inorganic and organometallic chemistry. However, reliable computational procedures to accurately describe the properties of such systems are not yet available. In this contribution, 18 experimentally characterized molecular uranium compounds, in oxidation states ranging from III to VI and with a variety of ligand environments, are studied computationally using density functional theory. The computed geometries and vibrational frequencies are compared with X-ray crystallographic, and infra-red and Raman spectroscopic data to establish which computational approach yields the closest agreement with experiment. NMR parameters and UV–vis spectra are studied for three and five closed-shell U(VI) compounds respectively. Overall, the most robust methodology for obtaining accurate geometries is the PBE functional with Grimme's D3 dispersion corrections. For IR spectra, different approaches yield almost identical results, which makes the PBE functional with Grimme's D3 dispersion corrections the best choice. However, for Raman spectra the dependence on functional is more pronounced and no clear recommendation can be made. Similarly, for 1H and 13C NMR chemical shifts, no unequivocal recommendation emerges as to the best choice of density functional, although for spin-spin couplings, the LC-ωPBE functional with solvent corrections is the best approach. No form of time-dependent density functional theory can be recommended for the simulation of the electronic absorption spectra of uranyl (VI) compounds; the orbitals involved in the transitions are not calculated correctly, and the energies are also typically unreliable. Two main approaches are adopted for the description of relativistic effects on the uranium centres: either a relativistic pseudopotential and associated valence basis set, or an all-electron basis set with the ZORA Hamiltonian. The former provides equal, if not better, agreement with experiment vs all-electron basis set calculations, for all properties investigated. © 2017 Elsevier B.V.
AB - Molecular uranium complexes are the most widely studied in actinide chemistry, and make a significant and growing contribution to inorganic and organometallic chemistry. However, reliable computational procedures to accurately describe the properties of such systems are not yet available. In this contribution, 18 experimentally characterized molecular uranium compounds, in oxidation states ranging from III to VI and with a variety of ligand environments, are studied computationally using density functional theory. The computed geometries and vibrational frequencies are compared with X-ray crystallographic, and infra-red and Raman spectroscopic data to establish which computational approach yields the closest agreement with experiment. NMR parameters and UV–vis spectra are studied for three and five closed-shell U(VI) compounds respectively. Overall, the most robust methodology for obtaining accurate geometries is the PBE functional with Grimme's D3 dispersion corrections. For IR spectra, different approaches yield almost identical results, which makes the PBE functional with Grimme's D3 dispersion corrections the best choice. However, for Raman spectra the dependence on functional is more pronounced and no clear recommendation can be made. Similarly, for 1H and 13C NMR chemical shifts, no unequivocal recommendation emerges as to the best choice of density functional, although for spin-spin couplings, the LC-ωPBE functional with solvent corrections is the best approach. No form of time-dependent density functional theory can be recommended for the simulation of the electronic absorption spectra of uranyl (VI) compounds; the orbitals involved in the transitions are not calculated correctly, and the energies are also typically unreliable. Two main approaches are adopted for the description of relativistic effects on the uranium centres: either a relativistic pseudopotential and associated valence basis set, or an all-electron basis set with the ZORA Hamiltonian. The former provides equal, if not better, agreement with experiment vs all-electron basis set calculations, for all properties investigated. © 2017 Elsevier B.V.
KW - Uranium
KW - DFT
KW - Geometry
KW - IR
KW - NMR
KW - Raman
KW - UV–Vis
U2 - 10.1016/j.jorganchem.2017.09.021
DO - 10.1016/j.jorganchem.2017.09.021
M3 - Article
VL - 857
SP - 58
EP - 74
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
ER -