Quantum chemical topology and natural bond orbital analysis of M–O covalency in M(OC<sub>6</sub>H<sub>5</sub>)<sub>4</sub> (M = Ti, Zr, Hf, Ce, Th, Pa, U, Np)
Victoria E. J. Berryman, Jacob J. Shephard, Tatsumi Ochiai, Amy N. Price, Polly L. Arnold, Simon Parsons, Nikolas Kaltsoyannis
Abstract
(M = Ti, Zr, Hf, Ce, Th, Pa, U, Np) using scalar relativistic hybrid density functional theory in conjunction with the Natural Bond Orbital (NBO), quantum theory of atoms in molecules (QTAIM) and interacting quantum atoms (IQA) approaches. The IQA exchange-correlation covalency metric is evaluated for the first time for actinides other than uranium, in order to assess its applicability in the 5f series. It is found to have excellent correlation with NBO and QTAIM covalency metrics, making it a promising addition to the computational toolkit for analysing metal-ligand bonding. Our range of metrics agree that the actinide-oxygen bonds are the most covalent of the elements studied, with those of the heavier group 4 elements the least. Within the early actinide series, Th stands apart from the other three elements considered, being consistently the least covalent.