Synthesis, Structural Characterization, and Catalytic Property of Group 4 Metal Carborane Compounds with a iPr2NB-Bridged Constrained-Geometry Ligand

Interaction of iPr2NB(C9H7)(C2B10H11) with 1 equiv of Zr(NMe2)4 gave a constrained-geometry zirconium amide [η5:σ-iPr2NB(C9H6)(C2B10H10)]Zr(NMe2)2 (2). Treatment of iPr2NB(C9H7)(C2B10H11) with 1 equiv of Ti(NMe2)4, however, led to the isolation of a deborated product (η5-C2B9H11)Ti(NMe2)2(HNMe2) (1). 2 reacted with excess Me3SiCl in toluene to give the chloro derivative [η5:σ-iPr2NB(C9H6)(C2B10H10)]ZrCl2 (4). Salt metathesis reaction between MCl4(THF)2 and [iPr2NB(C9H6)(C2B10H10)]Li2(Et2O)2 afforded [η5:σ-iPr2NB(C9H6)(C2B10H10)]MCl2 (M = Ti (3), Zr (4), Hf (5)). 3 was also prepared from the reaction of [iPr2NB(C9H6)(C2B10H10)]Li2(Et2O)2 with 1 equiv of TiCl3(THF)3, followed by addition of 0.5 equiv of PbCl2 in THF. Interaction of 2 with 4 equiv of Me3Al in toluene resulted in the isolation of [η5:σ-iPr2NB(C9H6)(C2B10H10)]ZrMe2 (6). 6 was also prepared via the reaction of 4 with 2 equiv of MeLi in THF. All of these compounds were fully characterized by various spectroscopic data and elemental analyses. The...