Decamethylytterbocene complexes of bipyridines and diazabutadines: multiconfigurational ground states and open-shell singlet formation

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Journal of the American Chemical Society

OSTI ID:956477

Bauer, Eric D ^[1]; Booth, C H ^[2]; Walter, M D ^[2]; Kazhdan, D ^[2]; Hu, Y - J ^[2]; Lukens, Wayne ^[2]; Maron, Laurent ^[3]; Eisentein, Odile ^[4]; Anderson, Richard ^[2]

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1. Los Alamos National Laboratory
2. LBNL
3. INSA TOULOUSE
4. UNIV MONTPELLIER 2

Partial ytterbium f-orbital occupancy (i.e. intermediate valence) and open-shell singlet Draft 12/formation are established for a variety of bipyridine and diazabutadiene adducts to decamethylytterbocene, (C{sub 5}Me{sub 5}){sub 2}Yb or Cp*{sub 2}Yb. Data used to support this claim includes ytterbium valence measurements using Yb Lm-edge x-ray absorption near-edge structure (XANES) spectroscopy, magnetic susceptibility and Complete Active Space Self-Consistent Field (CASSCF) multi configurational calculations, as well as structural measurements compared to density-functional theory (DFT) calculations. The CASSCF calculations indicate that the intermediate valence is the result of a multiconfigurational ground state wave function that has both an open-shell singlet f{sup 13} and a closed-shell singlet f{sup 14} component. A number of other competing theories for the unusual magnetism in these materials are ruled out by the presence of intermediate valence and its lack of any significant temperature dependence. These results have implications for understanding chemical bonding not only in organolanthanide complexes, but also for organometallic chemistry in general, as well as understanding magnetic interactions in nanopartic1es and devices.

• Research Organization: Los Alamos National Laboratory (LANL)
• Sponsoring Organization: DOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 956477
• Report Number(s): LA-UR-09-00072; LA-UR-09-72
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BIPYRIDINES
GROUND STATES
MAGNETIC SUSCEPTIBILITY
SELF-CONSISTENT FIELD
TEMPERATURE DEPENDENCE
VALENCE
WAVE FUNCTIONS