Synthese und Strukturen von Monoalkylamiden und -imiden des Titans / Synthesis and Structures of Monoalkylamides and -imides of Titanium

A new method for the preparation of monoalkylamides of composition Cp′TiCl₂NHR is reported. Me₃SnNHR (R = tBu 1a, CHiPr₂ 1b) reacts with Cp′TiCl₃ with elimination of Me₃SnCl to yield Cp′TiCl₂NHR (2) (2a: Cp′ = C₅H₅, R = tBu, 2b: Cp′ = Me₃SiC₅H₄, R = tBu, 2c: Cp′ = (Me₃Si)₂C₅H₃, R = tBu, 2d: Cp′ = Me₄C₅H, R = tBu, 2e: Cp′ = Me₅C₅, R = tBu, 2f: Cp′ = C₅H₅, R = CHiPr₂, 2g: Cp′ = Me₃SiC₅H₄, R = CHiPr₂, 2h: Cp′ = (Me₃Si)₂C₅H₃, R = CHiPr₂, 2i: Cp′ = Me₄C₅H, R = CHiPr₂, 2j: Cp′ = Me₅C₅, R = CHiPr₂). Compounds 2a-2j are stable and eliminate HCl only in the presence of a strong base to form (C₅H₅TiClNtBu)₂ (3a) or (Me₃SiC₅H₄TiClNtBu)₂ (3b) from 2a and 2b, respectively. In 3a the chlorine atoms are substituted by NHtBu groups in boiling THF by means of LiNHtBu to give (C₅H₅TiNHtBuNtBu)₂ (4). The reactions of 2e and 2b with LiN(SiMe₃)₂·Et₂O in the presence of pyridine yield Me₅C₅TiClNtBu · Py (5a) (Py = pyridine) and Me₃SiC₅H₄TiClNtBu·Py (5b), respectively. Compounds 2e and 5a have been characterized by X-ray crystal structural analysis.