Intermediate-Valence Tautomerism in Decamethylytterbocene Complexes of Methyl-Substituted Bipyridines

Journal Article · Tue Jan 25 04:00:00 EST 2011 · Journal of the American Chemical Society

OSTI ID:1005171

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

Multiconfigurational, intermediate valent ground states are established in several methyl-substituted bipyridine complexes of bispentamethylcyclopentadienylytterbium, Cp*{sub 2} Yb(Me{sub x}-bipy). In contrast to Cp*{sub 2} Yb(bipy) and other substituted-bipy complexes, the nature of both the ground state and the first excited state are altered by changing the position of the methyl or dimethyl substitutions on the bipyridine rings. In particular, certain substitutions result in multiconfigurational, intermediate valent open-shell singlet states in both the ground state and the first excited state. These conclusions are reached after consideration of single-crystal x-ray diffraction (XRD), the temperature dependence of x-ray absorption near-edge structure (XANES), extended x-ray absorption fine-structure (EXAFS), and magnetic susceptibility data, and are supported by CASSCF-MP2 calculations. These results place the various Cp*{sub 2}Yb(bipy) complexes in a new tautomeric class, that is, intermediate-valence tautomers.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Chemical Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1005171
• Report Number(s): LBNL-4249E
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Vol. 132; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION
BIPYRIDINES
EXCITED STATES
FINE STRUCTURE
GROUND STATES
ISOMERIZATION
MAGNETIC SUSCEPTIBILITY
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION