The Effect of Symmetric and Asymmetric NHCs on the Structure and Catalytic Properties of Dialkylgallium Alkoxides in the Ring-Opening Polymerization of <i>rac</i>-Lactide—Linking the Structure, Activity, and Stereoselectivity
作者:Anna Maria Dąbrowska、Aleksander Hurko、Krzysztof Durka、Maciej Dranka、Paweł Horeglad
DOI:10.1021/acs.organomet.1c00012
日期:2021.5.10
(6), possessing both small cavity and, in contrast to 4, restrained rotation of Ga–CNHC bond of the chelate ligand, has supported the effect of NHC on the structure and activity of Me2GaOR(NHC) complexes. DFT calculations of the energy profile of the consecutive ring-opening of two lactide molecules into Ga–Oalkoxide bonds of 1, 4, and Me2GaOMe(SIMes) have confirmed the effect of NHC on their stereoselectivity
操纵具有不对称N-杂环卡宾alkylgallium醇盐(NHC的)导致的基本上形成的结构“开”和“关”的在开环聚合催化镓中心(ROP)的状态外消旋-丙交酯(外消旋- LA),并已使NHC对Me 2 GaOR(NHC)复合物的活性和立体选择性的影响合理化。由于氮原子的取代程度不同,二甲基镓醇盐与不对称NHC的反应导致形成Me 2 GaOR(SI(Dipp-Mes))(OR = OMe(1),OCH 2 CH 2 OMe(2),OCH(我)CO 2我(3))和Me 2 GaOR(SI(Me-Mes))(OR = OMe(4),OCPh 2 Me(5))配合物(SI(Dipp-Mes)= 1-(二异丙基苯基)-3-(mesityl)-咪唑啉-2-亚基,SI(Me-Mes)= 1-(甲基)-3-(甲磺酰基)-咪唑啉-2-亚基)。的X射线分析1,2,4,和5显示的NHC的它们的结构,通过NHC的