合成N-杂环硅烯二氯前体{(C_6H_3-2，6-~1Pr_2)NCH}_2SiCl_2(~iPr=异丙基)的理论和实验研究(英文)

Theoretical and experimental study on the synthesis of dichloride precursor[(C_6H_3-2,6-~iPr_2)NCH]_2SiCl_2(~iPr=isopropyl) to the N-heterocyclic silylene

采用密度泛函B3LYP／6-31G^＊法，研究合成五元环二氯前体的起始物二亚胺（RNCH）2[1a R=C6H3-2，6-^iPr2（^iPr=isopropyl）；1b R=^tBu（^tBu=tert-butyl）]及关键中间体二锂衍生物2的几何构型、能量和电荷分布．表明二亚胺中，N原子上取代基团的立体结构及N原子周围的电子环境，对二亚胺1的性质的影响很强，二亚胺1a比1b稳定，要求锂试剂应具有更好的反应活性才能反应生成二锂衍生物2；二亚胺1a的电荷分布表明，锂试剂应拥有比金属锂更强的亲电子能力，才有利于二亚胺形成二锂衍生物．基于理论上的预测，在温和的条件下合成了N-杂环硅烯所需的二氯前体（RNCH）2[1a R=C6H3-2，6-^iPr2（^iPr=isopropyl）；1b R=^tBu（^tBu=tert-butyl）]并得到了很好的产率．

The B3LYP/6-31G^＊ level of theory has been used to study the geometries, energies, and distribution of charges on the starting diimines （RNCH）2 （R=C6H3-2,6-^ipr2 （^ipr = isopropyl） （1a）, ^tBu （^tBu = tert-butyl）（1b）） and the key intermediate dilithium derivatives 2 in the synthesis of the five-membered ring dichloride precursors （RNCH）2SiCl2 （R = C6H3-2,6-^iPr2 （3a）, ^tBu （3b））. The calculation results indicate that the properties of diimine 1 are strongly affected by the steric interference of the bulky substituent groups and electronic environment around the nitrogen atoms. The diimine la is more stable than the diimine lb, which requires that the lithium reagent should be more active. The charge population of diimine la demonstrates that the lithium reagent should possess highly electrophilic property, than lithium, which could react with the diimine to form the dilithium derivative. Based on the theoretical prediction, the dichloride precursor {（C6H3-2,6-^iPr2）NCH}2SiCl2 （3a） to the N-heterocyclic silylene was synthesized under a mild conditions and obtained in excellent yield.