Ruthenocene 3 ruthenocenophanes

When one iron atom in biferrocene is replaced by ruthenium, the second oxidation moves to a more positive potential (by - -400 mV), reflecting the greater difliculty in oxidizing ruthenocene (22). A similar effect is observed in the mixed-metal metallocenophane 4, (M = Fe, M = Ru) the more positive wave (peak potential pk - 0. 94 V) is due to an irreversible two-electron process presumably localized on the ruthenocene unit. Interestingly, [l.l]-ruthenocenophane 4 (M = M = Ru) oxidizes in a chemically reversible two-electron step ( = 0.38 V) to a persistent dication (25). 

H NMR spectra (DMSO-dg) of the Ag" complexes of ruthenocenophanes (81) and (82) suggest no interaction between the ruthenium and the complexed silver ion. In this case, the methylene protons attached to sulfur atoms were shifted more than the protons of the ruthenocene nucleus. H NMR spectra of the mercury(II) complexes of (80)-(82) suggest that there is signihcant interaction between ruthenium and the mercury(II). The P protons of the Cp rings were shifted further downfield than the a protons, and the ethylene protons exhibited very little downfield shift <85BCJ3540>. 

IR spectral data of the mercury(II) and silver(I) complexes of ruthenocenophanes (80)-(82) have been used to help determine the extent of interaction between the ruthenium atom of the ruthenocene unit and the encapsulated metal ion. The Cp—Ru—Cp ring tilting band around 430 cm is very instructive in these studies <85BCJ3540). 

The structures of the mixed ferrocene ruthenocene compounds a-carbonium [l]-(l,T)ferroceno[l] (l,r)ruthenocenophane -l-ylium hexafluorophosphate," the mercury-bridged ferrocenophane [ CsH4(CH3)2 2Fe-Hg-Fe CsH4(CH3)2 2](BF4 )2," and //-ferrocenium[l,l]ruthenocenophanes such as 14 have also been reported. ... 

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