The complexes [RR′CdNC 6 H 4 C(O)O-κ 2 N,O]Ni(η 3 -CH 2 CMeCH 2 ) (R, R′ ) -(CH 2 ) 5 -, 6; R ) Et, R′ ) Et, 7; R ) tBu, R′ ) H, 8) are prepared by reaction of the corresponding potassium salts with 11), which give poly(ethylene) when ethylene gas is added. This result is interesting in that the corresponding 2-(diphenylphosphino)benzoato and 2-(diphenylamino)benzoato complexes give mainly butene. Reactions of the potassium salts with Ni(η 3 -CH 2 C 6 H 5 )Cl(PMe 3 ) afford benzyl complexes,Additions of 2 equiv of B(C 6 F 5 ) 3 to 12 and 13 afford the zwitterionic). Complex 14 is rather unstable, and a bis ligand complex, [(CH 2 ) 5 CdNC 6 H 4 C{OB(C 6 F 5 ) 3 }O-κ 2 N,O] 2 Ni (16), is formed during recrystallization. Complexes 14 and 15 are highly active to ethylene polymerization, and activities reach 3000-4000 kg/((mol of Ni) h) at 75 psig pressure. Solid structures of 6, 9, 11, 15, and 16 were determined by X-ray crystallography.

[2,]zirconium dichloride (5), bearing methyl substituents on the carbons adjacent to a bridgehead carbon, was synthesized by key steps of the catalytic Pauson-Khand reaction and the retro-Diels-Alder reaction. The crystal structure of 5 was determined. The small angle (117.15°) between the two centroids of the cyclopentadienyls and a zirconium atom and the absence of any substituents on the positions with respect to the bridgehead carbon indicate that the coordination site for catalysis is widely opened. Compound 5, when activated with MAO, showed good performance for copolymerization of ethylene with a bulky monomer such as norbornene. The activity and norbornene incorporation ability are much better than those of [Ph 2 C(Fluo)(Cp)]ZrCl 2 .

Reaction of 2-(diphenylamino)benzoic acid with bis(methallyl)nickel(II) results in the dinuclear complex bis(η 3 -methallyl)bis{µ- [(2-diphenylamino)benzoato-O:O′]}dinickel(II) ( 1), where the nitrogen atom does not coordinate to the nickel. Addition of B(C 6 F 5 ) 3 to 1 in benzene affords the nitrogen-coordinating complex [(2diphenylamino)benzoate tris(pentafluorophenyl)borateκ 2 N,O](η 3 -methallyl)nickel(II) (2). The structures of 1 and 2 are confirmed by X-ray crystallography. Complex 2 shows good activity for norbornene polymerization, while complex 1 is inactive.

Deprotonation of the α-diimine compound {2,6-(CHMe2)2-C6H3}NC(CH3)C(CH3)N{2,6-(CHMe2)2-C6H3} with excess KH in THF gives dipotassium N,N‘-(1,2-dimethylene-1,2-ethanediyl)bis(2,6-diisopropylanilide) (1) in 75% yield. Reaction of 1 with bis(2-picolyl)zirconium dichloride generated in situ by the reaction of ZrCl4 and 2 equiv of (2-picolyl)potassium affords [N,N‘-(1,2-dimethylene-1,2-ethanediyl)bis(2,6-diisopropylanilido)-κ2 N,N‘]bis(2-picolyl)zirconium(IV) (2) in 35% yield. Similar reaction of 1 with LMCl3 (L = Cp, Cp*; M = Zr, Hf) gives the desired complexes {2,6-(CHMe2)2-C6H3}NC(CH2)C(CH2)N{2,6-(CHMe2)2-C6H3}MLCl (L = Cp*, M = Zr, 4; L = Cp*, M = Hf, 5; L = Cp, M = Zr, 6) in 79%, 94% and 54% yields, respectively. Reaction of the chloride complexes with MeMgBr affords the corresponding methyl complexes {2,6-(CHMe2)2-C6H3}NC(CH2)C(CH2)N{2,6-(CHMe2)2-C6H3}MLMe (L = Cp*, M = Zr, 7; L = Cp*, M = Hf, 8; L = Cp, M = Zr, 9) in 63%, 69% and 90% yields, respectively. The solid-state structure of 7 was determined. When 2, 7, or 9 is treated with 1 equiv of B(C6F5)3, one observes formation of the picolyl- or methyl-abstracted ion-paired complex in NMR spectra. When Al(C6F5)3 is added to 2, 8, or 9, the aluminum atom is coordinated by the methylene functionality of the enamide ligand to form zwitterionic complexes. The solid structure of a zwitterionic complex generated by the addition of Al(C3F5)3 to 8 was determined and confirms the molecular connectivity. The zwitterionic complexes are active to ethylene polymerization, while the ion-paired complexes are sluggish. Complexes 2 and 6 are highly active to the ethylene polymerization when they are activated with MAO.