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Title: Evaluating the electronic structure of formal Ln II ions in Ln II(C 5H 4SiMe 3) 3 1– using XANES spectroscopy and DFT calculations

Here, the isolation of [K(2.2.2-cryptand)][Ln(C 5H 4SiMe 3) 3], formally containing LnII, for all lanthanides (excluding Pm) was surprising given that +2 oxidation states are typically regarded as inaccessible for most 4f-elements. Herein, X-ray absorption near-edge spectroscopy (XANES), ground-state density functional theory (DFT), and transition dipole moment calculations are used to investigate the possibility that Ln(C 5H 4SiMe 3) 3 1– (Ln = Pr, Nd, Sm, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb and Lu) compounds represented molecular Ln II complexes. Results from the ground-state DFT calculations were supported by additional calculations that utilized complete-active-space multi-configuration approach with second-order perturbation theoretical correction (CASPT2). Through comparisons with standards, Ln(C 5H 4SiMe 3) 3 1– (Ln = Sm, Tm, Yb, Lu, Y) are determined to contain 4f 6 5d 0 (Sm II), 4f 13 5d 0 (Tm II), 4f 14 5d 0 (Yb II), 4f 14 5d 1 (Lu II), and 4d 1 (Y II) electronic configurations. Additionally, our results suggest that Ln(C 5H 4SiMe 3) 3 1– (Ln = Pr, Nd, Gd, Tb, Dy, Ho, and Er) also contain Ln II ions, but with 4f n 5d 1 configurations (not 4f n +1 5d 0). In these 4f n 5dmore » 1 complexes, the C 3h-symmetric ligand environment provides a highly shielded 5d-orbital of a' symmetry that made the 4f n 5d 1 electronic configurations lower in energy than the more typical 4f n+1 5d 0 configuration.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [1] ; ORCiD logo [4] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [1] ;  [5] ; ORCiD logo [2]
  1. Univ. of California, Irvine, CA (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Wisconsin, Madison, WI (United States)
  4. Stanford Univ., Palo Alto, CA (United States)
  5. Karlsruhe Institute of Technology, Karlsruhe (Germany)
Publication Date:
Report Number(s):
LA-UR-16-20691
Journal ID: ISSN 2041-6520; CSHCBM
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 8; Journal Issue: 9; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Inorganic and Physical Chemistry
OSTI Identifier:
1398908