Synthese und Struktur von 1.4-Diborylcyclopentadienen

Bis(trimethylsilyl)cyclopentadiene reacts with two equivalents of boron halides to the bis(dihalogenoboryl)cyclopentadienes I, II and III. Reactions of I, II and III with tetramethyltin and dimethylamine yield the dimethyl- and bis(dimethylamino)-substituted compounds IV and V. The fluoro compound VI is synthesized by the reaction of III with arsenic trifluoride. Addition of pyridine to I and II yields the adducts VII and VIII. Structure and bonding properties of I–VIII are discussed by ¹H-, ¹³C-, ¹¹B- and ¹⁹F.n.m.r- and by i.r. and m.s. data.