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

Abstract

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.