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Abstract

The titanocene complexes Cp'₂Ti(η²-Me₃SiC₂SiMe₃) (Cp' = Cp (1), Cp* (2)) react with pyrrole under the formation of the titanium(III) mono-N-pyrrolides Cp'₂Ti(NC₄H₄) (Cp' = Cp (6), Cp* (7)); whereas the corresponding zirconocene system Cp₂Zr(η²-Me₃SiC₂SiMe₃)(thf) (3) forms in a different reaction pathway first the Cp₂Zr(NC₄H₄)[C(SiMe₃)=CH(SiMe₃)] (8) and then the zirconium(IV) bis-N-pyrrolide Cp₂Zr(NC₄H₄)₂ (11). With Cp*₂Zr(η²-Me₃SiC₂SiMe₃) (4) and pyrrole, the zirconium(IV) mono-N-pyrrolide with an agostic alkenyl group Cp*₂Zr(NC₄H₄)[C(SiMe₃)=CH(SiMe₃)] (9) was obtained. In the reaction of the ethylenebistetrahydroindenyl (ebthi) complex rac-(ebthi)Zr(η²-Me₃SiC₂SiMe₃) (5) with 2,3,5,6-tetrafluoroaniline under N-H bond activation, a complex with an agostic alkenyl group rac-(ebthi)Zr(NH-C₆HF₄)[C(SiMe₃)=CH(SiMe₃)] (10) was formed. Compound 10 reacts with additional 2,3,5,6-tetrafluoroaniline to give the bisanilide rac-(ebthi)Zr(NH-C₆HF₄)₂ (12) which was obtained directly from 5 with two equivalents of 2,3,5,6-tetrafluoroaniline. In reactions of complex 5 with unsubstituted aniline to rac-(ebthi)Zr(NH-C₆H₅)₂ (13) and with pentafluorophenol to bisphenolate rac-(ebthi)Zr(O-C₆F₅)₂ (14), no intermediates could be isolated. The new reaction products 6, 9, 10, 12, 13 and 14 were investigated by X-ray crystallography.

Keywords: Metallocenes; Titanocenes; Zirconocenes; Organometallics; Heterocycles; Aromatics.

References: 46 live references.