摘要:
Addition of LiNH(2,6-Me2C6H3) (LiNHAr') to cis-2,5-bis((tosyloxy)methyl)tetrahydrofuran gave cis-2,5-(Ar'NHCH2)(2)(C4H6O) (H-2[1]). The reaction between Zr(NMe2)(4) and H-2[1] yielded [1]Zr(NMe2)(2), from which [1]ZrCl2 and [1]ZrMe2 were prepared readily. An unsymmetric relative of H-2[1], cis-2,5-(Ar'NHCH2)(ArNHCH2)(C4H6O) (H-2[2]; Ar = 2,6-i-Pr2C6H3), was also prepared via the imine of 5-(hydroxymethyl)furaldehyde. Cations of the type {[1]ZrMe-(PhNMe2)}[B(C6F5)(4)] and {[2]ZrMe(PhNMe2)}[B(C6F5)(4)], prepared in the reaction between the dimethyl species and [PhNHMe2][B(C6F5)(4)], could be observed and were stable toward exchange of free and coordinated dimethylaniline on the NMR time scale, while cations prepared in the reaction between the dimethyl species and [Ph3C][B(C6F5)(4)] did not have interpretable NMR spectra and appeared to be relatively unstable. Nevertheless, poly(1-hexene) that had a molecular weight approximately equal to the amount employed (up to 500 equiv) could be prepared by employing the latter at 0 degrees C in chlorobenzene.