Rare-earth metal dichloride and bis(alkyl) complexes containing amidinate-amidopyridinate ligands: synthesis, structure, and reactivity

A reaction of anhydrous yttrium chloride with an equimolar amount of lithium amidinate-amidopyridinate obtained in situ by metallation of N,N '-bis(2,6-dimethylphenyl)-N-{6-[(2,6-dimethylphenyl)amino]pyridin-2-yl}acetimidamide ((2,6-Me2C6H3)NH(2,6-C6H3N)N(2,6-Me2C6H3)C(Me)=N(2,6-Me2C6H3), (LH)-H-1) (1) with n-butyllithium in THF at-70 degrees C was used to synthesize the yttrium dichloride complex (L-1)YCl2(THF)(2) (2). The lutetium bis(alkyl) complex, namely, N'-(2,6-diisopropylphenyl)-N-(2,6-dimethylphenyl-N-{6-[(2,6-dimethylphenyl)amido]pyridin-2-6-yl}acetimidoamidinatebis(trimethylsilylmethyl)lutetium (4), was obtained by the reaction of N '-(2,6-diisopropylphenyl)-N-(2,6-dimethylphenyl)-N-(6-((2,6-dimethylphenyl)amino)pyridin-2-yl)acetimidamide ((2,6-Me2C6H3)NH(2,6-C6H3N)N-(2,6-Me2C6H3)C(Me)=N(2,6-(Pr2C6H3)-C-i), (LH)-H-2 (3)) with an equimolar amount of Lu(CH2SiMe3)(3)(THF)(2). Complex 4 was found to be very stable and did not show indications of C-H-activation and other kinds of disintegration in benzene or toluene solution even upon prolonged heating at 60 degrees C. The reaction of complex 4 with an equimolar amount of 2,6-diisopropylaniline in toluene solution at room temperature led to the formation of the lutetium alkyl-anilide complex (L-2)Lu(CH2SiMe3)(NH-2,6-(Pr2C6H3)-C-i) (5). A three-component system 4-AlBu3i-[X][B(C6F5)(4)] ([X] = [Ph3C], [PhNHMe2], the molar ratio of 1 : 10 : 1) was found to catalyze polymerization of isoprene.