Metal–ring interactions in actinide sandwich compounds: A combined normalized elimination of the small component and local vibrational mode study

Abstract

The relativistic Hamiltonian Normalised Elimination of the Small Component with atomic unitary transformation (NESCau) was used for the first time to calculate geometries and harmonic vibrational frequencies of actinide sandwich compounds ${\mathrm{An}(\mathrm{C}}_n{\mathrm{H}}_n{)}_2$ (An: Th, Pa, U, Np, Pu; $n=5-8$). In addition, the Local Vibrational Mode analysis, the Natural Bond Orbital analysis, and the Atoms in Molecules analysis were applied to quantitatively assess the intrinsic strength and the nature of the An-ring interactions. Our results show that actinide sandwich compounds prefer strong covalent interactions between actinide and carbon atoms, similar to those found for homologous ferrocene-type complexes ${\mathrm{Fe}(\mathrm{C}}_n{\mathrm{H}}_n{)}_2$. The metal centre rather than the ring size plays a key role in the strength of those interactions.

GRAPHICAL ABSTRACT

Keywords:

• NESCau
• actinides
• sandwich compounds
• local mode analysis
• intrinsic bond strength

Acknowledgements

The authors thank SMU for providing excellent computational resources.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was finally supported by the National Science Foundation [Grant Number CHE 1464906]. At Xi'an, this work was supported by the Double First-Class University Construction Project of Northwest University.