Influence of the Torsion Angle in 3,3鈥?Dimethyl-2,2鈥?bipyridine on the Intermediate Valence of Yb in (C5Me5)2Yb(3,3鈥?Me2-bipy)
详细信息 查看全文
- 作者：Gr茅gory Nocton ; Corwin H. Booth ; Laurent Maron ; Richard A. Andersen
- 刊名：Organometallics
- 出版年：2013
- 出版时间：October 14, 2013
- 年：2013
- 卷：32
- 期：19
- 页码：5305-5312
- 全文大小：368K
- 年卷期：v.32,no.19(October 14, 2013)
- ISSN：1520-6041
文摘
The synthesis and X-ray crystal structures of Cp*2Yb(3,3鈥?Me2bipy) and [Cp*2Yb(3,3鈥?Me2bipy)][Cp*2YbCl1.6I0.4]路CH2Cl2 are described. In both complexes, the NCCN torsion angles are approximately 40掳. The temperature-independent value of nf 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 nf value of 0.27; that is, the two configurations in the wave function are f13(蟺*1)1 and f14(蟺*1)0 in a ratio of 0.27:0.73, respectively, and the open-shell singlet lies 0.28 eV below the triplet state (nf accounts for f-hole occupancy; that is, nf = 1 when the configuration is f13 and nf = 0 when the configuration is f14). 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鈥?R2-bipy ligands approach each other, the value of nf and therefore the f13:f14 ratio reaches a maximum; conversely, the ratio is minimized as the disparity increases.