Metallocenophane

Ring-opening polymerization of strained metallocenophanes, mainly ferroceno-phanes with Si atom at the bridge, to give high-molecular-weight poly-(metallocenes) 99PAC1471. 

Silicon-bridged [l,l]metallocenophanes of type 40 in Scheme 14 represent another class of dinuclear compounds with the ligand system (30). The synthesis of the 1,1,12,12-tetramethyl [1,1] silaferrocenophane was reported by two groups only recently. In one procedure, the dilithium salt of dicyclopentadienyldimethylsilane was reacted with ferrous chloride to give a mixture of the metallocenophane with poly(ferrocenyldimethylsilane) (equation 55)124. In the other procedure, this compound was prepared in a multistep synthesis starting from dilithio ferrocene, as shown in equation 56125... 

Chalcogenide exchange, in semiconductor growth, 12, 26-27 Chalcogenides, with chromium, cubane clusters, 5, 308 Chalcogenido-bridged metallocenophanes, atom-abstraction-induced ROP, 12, 345... 

Living anionic ring-opening polymerization, strained metallocenophanes, 12, 326 Living polymerization acetylenes... 

Manners, Ian, Ring-Opening Polymerization of Metallocenophanes A New Route to... 

Figure 7.31 Ring-opening polymerization of metallocenophanes X = PR, SiR2, BR...

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). 

The dibromoselenurane 140 was also applied as a selenium transfer reagent in the formation of trichalcogen bonds in metallocenophanes. Thus,2-selena-l,3-dichalcogen[3]metallocenophanes 163 were obtained in high to moderate yields from the appropriate metallocene-1,1 -dithiols or -diselenols 164 upon treatment of 140 [75] (Scheme 19). 

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