Metallocenylborane, IV. Diborylverbindungen des Ferrocens und Cymantrens. : Metalocenylboranes, IV. Diboryl Compounds of Ferrocene and Cymantrene

Ferrocene reacts with BI₃ and BBr₃ to give 1,1′-bis(dihalogenboryl)ferrocenes; the cyclopentadienylring in cymantrene is twice borylated by BI₃. By halogen exchange with AsF₃ and AsCl₃, by methylation with Sn(CH₃)₄, by cleavage of (C₂H₅)₂O, by redox reaction with (CH₃S)₂ and by reaction with (C₂H₅)₂NH the corresponding diborylferrocenes are obtained. The air-sensitive halogenborylferrocenes form donor-acceptor compounds with Lewis bases. ¹H, ¹¹B and ¹³C NMR data reflect increasing π-acceptor properties with increasing Lewis acidity of the boryl groups.