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Title: Influence of the Torsion Angle in 3,3'-Dimethyl-2,2'-bipyridine on the Intermediate Valence of Yb in (C5Me5)2 Yb(3,3'-Me2-bipy)

The synthesis and X-ray crystal structures of Cp-2*Yb(3,3'-Me(2)bipy) and [Cp-2 Yb(3,3'-Me(2)bipy)][Cp-2 YbCl1.6I0.4]center dot CH2Cl2 are described. In both complexes, the NCCN torsion angles are approximately 40 degrees. The temperature-independent value of n(f) of 0.17 shows that the valence of ytterbium in the neutral adduct is multiconfigurational, in reasonable agreement with a CASSCF calculation that yields a n(f) value of 0.27; that is, the two configurations in the wave function are f(13)(pi(1))(1) and f(14)(pi(1))(0) in a ratio of 0.27:0.73, respectively, and the open-shell singlet lies 0.28 eV below the triplet state (n(f) accounts for f-hole occupancy; that is, n(f) = 1 when the configuration is f(13) and n(f) = 0 when the configuration is f(14)). A correlation is outlined between the value of nf and the individual ytterbocene and bipyridine fragments such that, as the reduction potentials of the ytterbocene cation and the free x,x'-R-2-bipy ligands approach each other, the value of nf and therefore the f(13):f(14) ratio reaches a maximum; conversely, the ratio is minimized as the disparity increases.
Authors:
; ; ;
Publication Date:
OSTI Identifier:
1163867
Report Number(s):
LBNL-6698E
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Organometallics; Journal Volume: 32; Journal Issue: 19; Related Information: Journal Publication Date: 2013
Research Org:
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
Sponsoring Org:
Chemical Sciences Division
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY DECAMETHYLYTTERBOCENE COMPLEXES; DIPERCHLORATE MONOHYDRATE; LANTHANIDE COMPLEXES; GROUND-STATE; BIPYRIDINES; 1,1'-BIISOQUINOLINE; COORDINATION; COVALENCY; EXCHANGE