Advancing the understanding of M–O covalency in isostructural M–OSiMe3 (M = Ce, Th, U) complexes

Abstract

The covalency of f-block elements is particularly important for us to understand the bonding nature of their chemical bonds. In this work, a series of isostructural 4f and 5f complexes: [M(Trapen^TMS)(OSiMe₃)] (M = Ce (2Ce), Th (2Th), U (2U)); Trapen^TMS = N(CH₂Ph(o-NSiMe₃)₃) are synthesized through a salt-elimination method. These 2M complexes were characterized by single crystal X-ray diffraction, NMR, FT-IR, and UV-vis-NIR spectroscopies. The theoretical calculation based on density functional theory shows that the 4f/5f orbitals play a key role in the M–O bonding interaction and the covalency follows the trend of Ce–O < Th–O < U–O.