| Budget Amount *help |
¥5,800,000 (Direct Cost: ¥5,800,000)
Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1986: ¥4,800,000 (Direct Cost: ¥4,800,000)
|
|---|
| Research Abstract |
For the purpose of determining basic factors controlling the intramolecular electron-transfer between metal centers observed in the mixed-valence biferrocene derivatives, the mixed-valence salts of biferrocence derivatives having two kinds of substituents on their 1' and 1''' positions were investigted by means of ^<57>Fe-M ssbauer spectroscopy.
The ^<57>Fe-M ssbauer spectra of 1'-bromo-1'''-iodobiferrocenium and 1'-chloro-1'''- iodobiferrocenium triiodides showed the averaged-valence type, that is, one doublet even at 4.2K, similar to those of the triiodide salts of 1',1'''-dihalobiferroxcenes having two identical halogen substituents. On the other hand, the ^<57>Fe-M ssbauer spectra of 1'-alkylbiferrocenium triiodides showed the mixed-valence type, that is, two doublets at any temperature in the range from 4.2K to 298K. Therefore, it is reasonable to conclude that the effect of halogen substitution on biferrocenium cation is large enough to cause averaging the valence state of the cation, but little difference was observed in the effects of individual halogen substituents on the valence state of the cation. On the other hand, the effect of single alkyl substitution on the biferrocenium cation is not so large enough to cause the temperature dependence of the valence state of cation. It seems likely that, in the case of the dihalobiferrocenium triiodides, the cations in solid are located in a suitable environment favorable to the averaging of valence states of iron atoms in the cation, but in the case of the monoalkylbiferrocenium salts, they are not.
|
