Zirconium Complexes That Contain a Diamido O-Donor Ligand with a Restricted Geometry

Addition of LiNH(2,6-Me 2 C 6 H 3 ) (LiNHAr‘) to cis -2,5-bis((tosyloxy)methyl)tetrahydrofuran gave cis -2,5-(Ar‘NHCH 2 ) 2 (C 4 H 6 O) (H 2 [ 1 ]). The reaction between Zr(NMe 2 ) 4 and H 2 [ 1 ] yielded [ 1 ]Zr(NMe 2 ) 2, from which [ 1 ]ZrCl 2 and [ 1 ]ZrMe 2 were prepared readily. An unsymmetric relative of H 2 [ 1 ], cis -2,5-(Ar‘NHCH 2 )(ArNHCH 2 )(C 4 H 6 O) (H 2 [ 2 ]; Ar = 2,6- i -Pr 2 C 6 H 3 ), was also prepared via the imine of 5-(hydroxymethyl)furaldehyde. Cations of the type {[ 1 ]ZrMe(PhNMe 2 )}[B(C 6 F 5 ) 4 ] and {[ 2 ]ZrMe(PhNMe 2 )}[B(C 6 F 5 ) 4 ], prepared in the reaction between the dimethyl species and [PhNHMe 2 ][B(C 6 F 5 ) 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 [Ph 3 C][B(C 6 F 5 ) 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 °C in chlorobenzene.