Neutral and Cationic Alkyl and Amido Group 3 Metal Complexes of Amidine-Amidopyridinate Ligands: Synthesis, Structure, and Polymerization Catalytic Activity

作者：Rad' kov Vasily; Roisnel Thierry; Trifonov Alexander; Carpentier Jean Francois^*; Kirillov Evgeny

来源：European Journal of Inorganic Chemistry, 2014, 2014(25): 4168-4178.

DOI：10.1002/ejic.201402362

• Ligand design
• N ligands
• Agostic interactions
• Polymerization

Alkane and amine elimination reactions between the amidine-aminopyridine proligands ((NNNCMeNR2)-N-R1-C-R1) H [R-1 = R-2 = Me (1a), R-1 = H, R-2 = Me (1b), R-1 = Me, R-2 = iPr (1c)] and the precursors [Ln(CH2SiMe3)(3)(thf)(2)] (Ln = Sc and Y) and [Ln{N(SiHMe2)(2)}(3)(thf)(x)] (Ln = Sc, Y, and La) have been investigated. Bulky 1c and [Ln(CH2SiMe3)(3)(thf)(2)] (Ln = Sc and Y) selectively afforded dialkyl complexes 2c-Sc and 2c-Y. Yttrium and lanthanum diamido complexes 3a-Y, 3b-Y, 3c-Y, and 3c-La were synthesized and isolated in high yields; however, similar aminolysis reactions to prepare the scandium analogues were unsuccessful. Detailed 29Si NMR spectro-scopic studies combined with X-ray crystallography revealed the presence of beta-Si-H center dot center dot center dot Ln agostic interactions in the diamido complexes. Cationic monoamido complex 4a-Y was obtained from the reaction of 3a-Y with [Et3NH]+[BPh4](-). Both the dialkyl and diamido complexes, activated with [Ph3C]+[B(C6F5)(4)](-)/AliBu(3) or [PhNMe2H](+)[B(C6F5)(4)](-)/AliBu(3), were found to be moderately active at 60 degrees C in the trans-1,4-selective polymerization of isoprene, and the diamido complexes promoted the ring-opening polymerization of rac-lactide with moderate activities.

• 出版日期2014-9