Studies related to the chloro titanium and zirconium complexes with [η5-Cyclopentadienyldi(silylamido)] Ligands

Abstract

Trichloro complexes [M{η5-C5H3[SiMe2(NHtBu)]2}Cl3] [M = Zr (2), Ti (3)] have been synthesized by reaction of the corresponding chlorides MCl4 with the lithium salt LiC5H3[SiMe2(NHtBu)]2 (1). Complexes 2 and 3 react with 2 equiv. of TiCl4 in toluene at 110°C to afford the di(chlorosilyl) derivatives [M{η5-C5H3(SiMe2Cl)2}Cl3] [M = Ti (5), Zr (8)]. Intermediate formation of [Ti{η5-C5H3[SiMe2(NHtBu)](SiMe2Cl)}Cl3] (4) has been proven by NMR spectroscopy. Reaction of 1 with TiCl4 (2 equiv.) in toluene at 110 °C in the presence of excess NEt3 has yielded the chloro-silyl complex [Ti{η5-C5H3(SiMe2Cl)(SiMe2-η1-NtBu)}Cl2] (7) through the intermediate formation of the amino-silyl derivative [Ti{η5-C5H3[SiMe2(NHtBu)] (SiMe2-η1-NtBu)}Cl2] (6). Reactions of di-ansa-[M{η5-C5H3(SiMe2-η1-NtBu)2}R] and ansa-[M{η5-C5H3[SiMe2(NHtBu)] (SiMe2-η1-NtBu)}R2] (M = Ti, Zr; R = NMe2, CH2Ph) complexes with NEt3·HCl have afforded the dichloro derivatives [M{η5-C5H3[SiMe2(NHtBu)] (SiMe2-η1-NtBu)}Cl2] [M = Ti (6), Zr (12)], the amine-coordinated zirconium compound [Zr{η5-C5H3 [SiMe2(NHtBu)](SiMe2-η1-NtBu)} Cl2(NMe2H)] (9) and the chloro-benzyl titanium complex [Ti{η5-C5H3[SiMe2(NHtBu)](SiMe2-η1-NtBu)}Cl(CH2Ph)] (11). Formation of the mono-substituted chloroamido zirconium complex [Zr{η5-C5H3[SiMe2 (NHtBu)](SiMe2-η1-NtBu)}Cl(NMe2)] (10) by the reaction of [Zr{η5-C5H3[SiMe2(NHtBu)] (SiMe2-η1-NtBu)}(NMe2)2] with SiClMe3 has been monitored in C6D6 by NMR spectroscopy. All of the new chloro complexes have been characterized by elemental analyses and NMR spectroscopy and the X-ray crystal structure of [Ti(η5-C5H3{SiMe2(NHtBu)}2)Cl3] (3) has been studied by diffraction methods.