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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=C_6H_3-2,6-~iPr_2(~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= C_6H_3-2,6-~iPr_2(~iPr=isopropyl);1bR=~tBu(~tBu=tert-butyl)]并得到了很好的产率.
The starting diimine (RNCH) 2 [1aR = C_6H_3-2,6- ~ iPr_2 (~ iPr = isopropyl) was synthesized by the density functional theory B3LYP / 6-31G * ); 1b R = ~ tBu (~ tBu = tert-butyl)] and the geometry, energy and charge distribution of the key intermediate di-lithium derivative 2. It is shown that the stereochemistry of the substituent on the N atom in the diimine And N atoms around the electronic environment, a strong impact on the nature of diimine 1, diimine 1a than 1 b stable, requiring lithium reagent should have a better reactivity to react to form a dilithio derivative 2; diimine The charge distribution of 1a shows that the lithium reagent should have a stronger electrophilic ability than lithium metal, which is favorable for the formation of di-lithium derivatives by diimine.Based on the theoretical predictions, N-heterocyclic silicon (RNCH) 2 [1aR = C_6H_3-2,6- ~ iPr_2 (~ iPr = isopropyl); 1bR = ~ tBu (~ tBu = tert-butyl)] was obtained and a good Yield.