Zirconium complexes of fluorinated aryl diamides

The reaction of excess (ArNHLi)-N-F with (ICH2CH2OCH2)(2) affords the new diamines ((ArNHCH2CH2OCH2)-N-F)2 (1, Ar-F = C6F5; 2, Ar-F = 3,5-C6H3(CF3)(2)) in moderate yield. Direct protonolysis of Zr(CH2Ph)(n)Cl4-n (n = 2-4) or Zr[N(SiMe3)(2)](n)Cl4-n (n = 2, 3) with 1 or 2 (1 equiv) affords the zirconium complexes Zr((ArNCH2CH2OCH2)-N-F)(2)(X)(Y) (Ar-F = C6F5: 3, X = Y = Cl; 4, X = N(SiMe3)(2,) Y = Cl; 5, X = Cl, Y = CH2Ph; 6, X = Y = CH2Ph. Ar-F = 3,5-C6H3(CF3)(2): 7, X = Y = Cl; 8, X = Y = CH2Ph). The structures of 1, 4, 5, and 7 were established by X-ray crystalIography with the zirconium complexes 4, 5, and 7 all adopting a monocapped trigonal bipyramidal geometry in the solid state. However, in solution, these complexes display higher symmetry due to rapid ligand rearrangement. The silylamido complex 4 shows restricted rotation of the C6F5 rings in solution (DeltaG(double dagger) = 49 +/- 3 kJ mol(-1)). Abstraction of a benzyl group from 6 by B(C6F5)(3) affords {Zr [CH2OCH2CH2N(C6F5)](2)(CH2Ph)}(+){(PhCH2)B(C6F5)(3)} - (9) This complex shows evidence for eta (2)-benzyl coordination and does not polymerize ethylene at room temperature. Treatment of 3 with excess MAO (500 equiv) and ethylene(1 atm, 50 degreesC) affords polyethylene at a modest rate (3.2 kg mol(-1) Zr h(-1)).