作者：Bo Liu； Dongmei Cui； Jia Ma； Xuesi Chen and Xiabin Jing
关键字：C-H activation, lanthanides, N ligands, N,P ligands, ring-opening polymerization
论文来源：期刊
具体来源：http://onlinelibrary.wiley.com/doi/10.1002/chem.200601125/full
发表时间：2006年

Anilido phosphinimino ancillary ligand H2L1 reacted with one equivalent of rare earth metal trialkyl [Ln{CH2Si(CH3)3}3(thf)2] (Ln=Y, Lu) to afford rare earth metal monoalkyl complexes [L1LnCH2Si(CH3)3(THF)] (1?a: Ln=Y; 1?b: Ln=Lu). In this process, deprotonation of H2L1 by one metal alkyl species was followed by intramolecular CH activation of the phenyl group of the phosphine moiety to generate dianionic species L1 with release of two equivalnts of tetramethylsilane. Ligand L1 coordinates to Ln3+ ions in a rare C,N,N tridentate mode. Complex l?a reacted readily with two equivalents of 2,6-diisopropylaniline to give the corresponding bis-amido complex [(HL1)LnY(NHC6H3iPr2-2,6)2] (2) selectively, that is, the CH activation of the phenyl group is reversible. When 1?a was exposed to moisture, the hydrolyzed dimeric complex [{(HL1)Y(OH)}2](OH)2 (3) was isolated. Treatment of [Ln{CH2Si(CH3)3}3(thf)2] with amino phosphine ligands HL2-R gave stable rare earth metal bis-alkyl complexes [(L2-R)Ln{CH2Si(CH3)3}2(thf)] (4?a: Ln=Y, R=Me; 4?b: Ln=Lu, R=Me; 4?c: Ln=Y, R=iPr; 4?d: Ln=Y, R=iPr) in high yields. No proton abstraction from the ligand was observed. Amination of 4?a and 4?c with 2,6-diisopropylaniline afforded the bis-amido counterparts [(L2-R)Y(NHC6H3iPr2-2,6)2(thf)] (5?a: R=Me; 5?b: R=iPr). Complexes 1?a,b and 4?a–d initiated the ring-opening polymerization of d,l-lactide with high activity to give atactic polylactides.