Liu Bo, Cui Dongmei, Ma Jia, Chen Xuesi, Jing Xiabin
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, China.
Chemistry. 2007;13(3):834-45. doi: 10.1002/chem.200601125.
Anilido phosphinimino ancillary ligand H(2)L(1) reacted with one equivalent of rare earth metal trialkyl [Ln{CH(2)Si(CH(3))(3)}(3)(thf)(2)] (Ln=Y, Lu) to afford rare earth metal monoalkyl complexes [L(1)LnCH(2)Si(CH(3))(3)(THF)] (1 a: Ln=Y; 1 b: Ln=Lu). In this process, deprotonation of H(2)L(1) by one metal alkyl species was followed by intramolecular C--H activation of the phenyl group of the phosphine moiety to generate dianionic species L(1) with release of two equivalnts of tetramethylsilane. Ligand L(1) coordinates to Ln(3+) 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 [(HL(1))LnY(NHC(6)H(3)iPr(2)-2,6)(2)] (2) selectively, that is, the C--H activation of the phenyl group is reversible. When 1 a was exposed to moisture, the hydrolyzed dimeric complex {(HL(1))Y(OH)}(2)(2) (3) was isolated. Treatment of [Ln{CH(2)Si(CH(3))(3)}(3)(thf)(2)] with amino phosphine ligands HL(2-R) gave stable rare earth metal bis-alkyl complexes [(L(2-R))Ln{CH(2)Si(CH(3))(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 [(L(2-R))Y(NHC(6)H(3)iPr(2)-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.
苯胺基膦亚胺辅助配体H₂L₁与一当量的稀土金属三烷基化合物[Ln{CH₂Si(CH₃)₃}(3)(thf)₂]（Ln = Y，Lu）反应，得到稀土金属单烷基配合物[L₁LnCH₂Si(CH₃)₃(THF)]（1a：Ln = Y；1b：Ln = Lu）。在此过程中，一个金属烷基物种使H₂L₁去质子化，随后膦部分苯基的分子内C-H活化，生成双阴离子物种L₁，并释放出两当量的四甲基硅烷。配体L₁以罕见的C,N,N三齿模式与Ln³⁺离子配位。配合物1a很容易与两当量的2,6-二异丙基苯胺反应，选择性地生成相应的双酰胺基配合物[(HL₁)LnY(NHC₆H₃iPr₂-2,6)₂]（2），也就是说，苯基的C-H活化是可逆的。当1a暴露于湿气中时，分离得到水解的二聚配合物{(HL₁)Y(OH)}₂₂（3）。用氨基膦配体HL₂-R处理[Ln{CH₂Si(CH₃)₃}(3)(thf)₂]，高产率地得到稳定的稀土金属双烷基配合物[(L₂-R)Ln{CH₂Si(CH₃)₃}₂(thf)]（4a：Ln = Y，R = Me；4b：Ln = Lu，R = Me；4c：Ln = Y，R = iPr；4d：Ln = Y，R = iPr）。未观察到配体的质子提取。用2,6-二异丙基苯胺对4a和4c进行胺化，得到双酰胺基对应物[(L₂-R)Y(NHC₆H₃iPr₂-2,6)₂(thf)]（5a：R = Me；5b：R = iPr）。配合物1a、b和4a - d引发了d，l-丙交酯的开环聚合，具有高活性，得到无规聚丙交酯。
