摘要:
The compound [Zr(eta-C5H4CMe2C6H4Me-p)Cl-3(dme)] (1) has been prepared. Methylation affords the compound [Zr(eta-C5H4CMe2C6H4Me-p)Me-3] (2), and benzylation of 1 yields [Zr- (eta-C5H4CMe2C6H4Me-p)(CH2Ph)(3)] (3). Reaction of 2 with [Ph3C](+)[B(C6F5)(4)](-) at -60 degrees C gives the ansa complex [Zr(eta:eta-C5H4CMe2C6H4Me-p)Me-2](+)[B(C6F5)(4)](-) (4a), which has been characterized by 1D and 2D NMR spectroscopy. Reaction of 2 with an excess (1.5 equiv) of B(C6F5)(3) yields not only the ansa complex [Zr(eta:eta-C5H4CMe2C6H4Me-p)Me-2](+)[MeB(C6F5)(3)](-) (4b) but also the novel cationic zwitterionic ansa complex [Zr(eta:eta-C5H4CMe2C6H4Me-p)(mu-MeBC6F5)(3))](+)[MeB(C6F5)(3)](-) (5) The dynamic behavior of complexes 4b and 5 was extensively studied by NMR spectroscopy. Reaction of 3 with [Ph3C](+)[B(C6F5)(4)](-) at -60 degrees C yields the ansa complex [Zr(eta:eta-C5H4CMe2C6H4Me-p)(CH2Ph)(2)](+)[B(C6F5)(4)](-) (6), containing sigma-bound benzyl ligands.