Abstract
The octacarbonyl cation and anion complexes of actinide metals [An(CO)8]+/− (An=Th, U) are prepared in the gas phase and are studied by mass‐selected infrared photodissociation spectroscopy. Both the octacarbonyl cations and anions have been characterized to be saturated coordinated complexes. Quantum chemical calculations by using density functional theory show that the [Th(CO)8]+ and [Th(CO)8]− complexes have a distorted octahedral (D 4h) equilibrium geometry and a doublet electronic ground state. Both the [U(CO)8]+ cation and the [U(CO)8]− anion exhibit cubic structures (Oh) with a 6A1g ground state for the cation and a 4A1g ground state for the anion. The neutral species [Th(CO)8] (Oh; 1A1g) and [U(CO)8] (D 4h; 5B1u) have also been calculated. Analysis of their electronic structures with the help on an energy decomposition method reveals that, along with the dominating 6d valence orbitals, there are significant 5f orbital participation in both the [An]←CO σ donation and [An]→CO π back donation interactions in the cations and anions, for which the electronic reference state of An has both occupied and vacant 5f AOs. The trend of the valence orbital contribution to the metal–CO bonds has the order of 6d≫5f>7s≈7p, with the 5f orbitals of uranium being more important than the 5f orbitals of thorium.
Highlights
The classification of chemical elements in the periodic table, introduced 150 years ago by Mendeleyev,[1] is based on the elec-[a] Dr C
In a recent analysis of octacarbonyl anion complexes of the late lanthanides [Ln(CO)8]À (Ln = Tm, Yb, Lu), we found that the 32-electron rule is valid in the systems that have 32–34 valence electrons when the symmetry of the orbitals is considered.[10]
We extended our work to carbonyl complexes of the early actinide atoms thorium and uranium
Summary
The classification of chemical elements in the periodic table, introduced 150 years ago by Mendeleyev,[1] is based on the elec-. The bonding situation was studied by energy decomposition analysis (EDA)[26] together with the natural orbitals for chemical valence (NOCV)[27] method by using the ADF 2017.01 program www.chemeurj.org package.[28] The EDA-NOCV[29] calculations were performed at the B3LYP-D3(BJ)/TZ2P[30] level by using the B3LYP-D3(BJ)/def2TZVPPD/ECP optimized geometries, in which the scalar relativistic effects were included for An by adopting the zeroth-order regular approximation (ZORA).[31] In the EDA method, the intrinsic interaction energy (DEint) between two fragments is decomposed into four energy components [Eq (1)]: DEint 1⁄4 DEelstat þ DEPauli þ DEdisp þ DEorb ð1Þ. The terms FTSÀk, Àk and FTSk,k are diagonal transitionstate (TS) Kohn–Sham matrix elements that correspond to NOCVs with the respective eigenvalues vk.[29]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
