Zirconium indenylamido complexes: synthesis and reactivity: Crystal structure of [Zr(Ind)2(NC3H6)2]

Reactions of [ZrInd(NMe2)3] (1) with Me3SiCl afforded [ZrInd(NMe2)2Cl] (2), [ZrInd(NMe2)Cl2] (3) and [ZrIndCl3]n (4) in high yields (≥90%). [ZrIndCl3(dme)] (5) was obtained either from 4 and dme or by a one-pot reaction from [ZrInd(NMe2)3], Me3SiCl and dme. Treatment of [ZrInd(NMe2)2Cl] with LiMe gave [ZrInd(NMe2)2Me] (6), and in similar reaction conditions [ZrInd2Me2] (10) was obtained from [ZrInd(NMe2)Cl2]. Whereas the reaction of 2 with LiN(H)tBu produced {[ZrInd(NMe2)2[N(H)tBu]} (7), the addition of LiN(H)tBu to [TiInd(NMe2)2Cl] afforded [Ti(NMe2)2(μ-NtBu)]2 (9) in quantitative yield. {TiInd(NMe2)2[N(H)tBu]} was identified by NMR as an intermediate in the synthesis of 9, and two isomeric forms corresponding to the parallel (8a) and perpendicular (8b) orientations of the indenyl and N(H)tBu ligands were characterised. The addition of an excess of azetidine to 1 gave [ZrInd2(NC3H6)2] (11), the molecular structure of which was determined by X-ray crystallography. Preliminary studies showed that 3–methylaluminoxane (MAO) polymerises ethylene and propylene, whereas [TiInd(NMe2)Cl2], 12–MAO, only polymerises ethylene.