J. Phys. IV France 7 (1997) C2-653-C2-654
Molecular Structures and Electronic Structures of Transition-Metal Mixed-Sandwich Complexes, [CpFe(II)(PhX)](+1) and FerroceneJ. Yasui1, H. Maeda2, S. Emura3, M. Imahashi1, K. Shoki1, K. Shiomi1, T. Kodama1 and N. Fukushima4
1 TOYOBO Research Institute, Katata 2-2, Ohtsu, Shiga 520-02, Japan
2 Faculty of Science, Okayama University, Okayama 700, Japan
3 ISIR Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567, Japan
4 CRAY RESEARCH JAPAN LTD. Chiyoda-ku, Tokyo 102, Japan
The local structures of the transition-metal mixed-sandwich complexes, [CpFe(Il)(PhX)](+1), (Cp =η5- cyclopentadienyl ; PhX =η6-benzene and its derivatives), have been studied by EXAFS and density-functional theory (DFT). Fe K-edge EXAFS spectra were measured at 10K and analysed by a two-shell model, and DFT calculations were made to predict more detailed molecular structures. Both methods give the Fe-C distance of ferrocene in good agreement with electron diffraction in gas phase. For the mixed-sandwich complexes, EXAFS and DFT provide similar structures that the Fe-C distance in the Ph-pyramid is slightly longer than that in the Cp-pyramid for all the derivatives except the [CpFe(C6(CH3)6)](+) complex. It is found by DFT that the Fe-C(X) distance in the PhX-pyramid changes depending on whether the substituent X is an electron donnor or an electron acceptor. We discuss the dependence from the valence MO's and the Mulliken population analysis.
© EDP Sciences 1997