Synthesis, structural characterization and 57Fe-Mössbauer spectra of ferrocenylhexasilanes

Linear and cyclic ferrocenylhexasilanes 1,6-Fc–Si6Me12–X [X=Me, –C6H4CHC(CN)2], 1,3- and 1,4-Fc–Si6Me10–X [X=Me, –C6H4CHC(CN)2], have been synthesized and their Mössbauer spectra have been measured. All compounds possess localized electronic structures on the Mössbauer timescale and partial Fe(III) character of the iron atom due to Cp→(Sin) electron transfer. The Mössbauer data obtained, furthermore, indicate considerable aryl–ferrocenyl interaction via the hexasilane moiety. The single crystal X-ray structures of 1,3- and 1,4-Fc–Si6Me10–C6H4CHC(CN)2 exhibit the cyclohexasilane ring in chair conformation with the bulky Fc- and aryl substituents in equatorial positions.