Decamethylytterbocene Complexes of Bipyridines and Diazabutadienes: Multiconfigurational Ground States and Open-Shell Singlet Formation

Journal Article · Wed Apr 22 04:00:00 EDT 2009 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja809624w· OSTI ID:962702

Booth, Corwin H; Walter, Marc D; Kazhdan, Daniel; Hu, Yung-Jin; Lukens, Wayne W; Bauer, Eric D; Maron, Laurent; Eisenstein, Odile; Andersen, Richard A

Partial ytterbium f-orbital occupancy (i.e., intermediate valence) and open-shell singlet formation are established for a variety of bipyridine and diazabutadiene adducts with decamethylytterbocene, (C5Me5)2Yb, abbreviated as Cp*2Yb. Data used to support this claim include ytterbium valence measurements using Yb LIII-edge X-ray absorption near-edge structure spectroscopy, magnetic susceptibility, and complete active space self-consistent field (CASSCF) multiconfigurational calculations, as well as structural measurements compared to density functional theory 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 f13(?*)1, where pi* is the lowest unoccupied molecular orbital of the bipyridine or dpiazabutadiene ligands, and a closed-shell singlet f14 component. A number of other competing theories for the unusual magnetism in these materials are ruled out by the lack of temperature dependence of the measured intermediate valence. These results have implications for understanding chemical bonding not only in organolanthanide complexes but also for f-element chemistry in general, as well as understanding magnetic interactions in nanoparticles and devices.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Chemical Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 962702
• Report Number(s): LBNL-2026E
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 18 Vol. 131; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ADDUCTS
BIPYRIDINES
BONDING
CHEMISTRY
FUNCTIONALS
GROUND STATES
Intermediate valence
molecular Kondo effect
organometallic
ytterbocene
MAGNETIC SUSCEPTIBILITY
MAGNETISM
SELF-CONSISTENT FIELD
SPECTROSCOPY
TEMPERATURE DEPENDENCE
VALENCE
WAVE FUNCTIONS
YTTERBIUM