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采用密度泛函[DFT]和自然键轨道理论[NBO]及高级电子耦合簇[CCSD(T)]和电子密度拓扑分析[AIM]方法,研究了单重态二卤卡宾CX_2(x=F,Cl,Br)与乙醛CH_3CHO中C-C键的插入反应及其环加成的反应机理.在B3LYP/6-31G(d)水平上优化了各驻点构型,用频率分析和内禀反应坐标法(IRC)对过渡态进行了验证,计算了各物种的CCSD(T)/6-31G(d,p)单点能量.用经Wigner校正的Eyring过渡态理论分别计算了1大气压下主反应通道的热力学与动力学性质,并对反应通道中构型进行了自然键轨道及电子密度拓扑分析.结果表明,CF_2与CH_3CHO反应的主产物是P2_F[CH_3CF-2CHO:插入CH_3CHO中C-C键,反应Ⅰ(2)],而CCI_2及CBr_2与CH_3CHO反应的主产物是P1_cl[Cl_2COCHCH_3:成环反应Ⅱ(1)]及P1 B[Br_2COCHCH_3:成环反应Ⅲ(1)],1大气压下,反应I(2)和Ⅱ(1)及Ⅲ(1)进行的适宜温度范围分别为400～1300 K和400～1000 K.
Density functional theory [DFT] and natural bond orbital theory [NBO] and advanced electron-coupled cluster [CCSD (T)] and electron density topological analysis [AIM] Cl, Br) and the CC bond in the acetaldehyde CH_3CHO and the cycloaddition reaction mechanism of the reaction were optimized at the B3LYP / 6-31G (d) level, with frequency analysis and intrinsic reaction coordinate The transition state was validated by IRC, and the single-point energy of CCSD (T) / 6-31G (d, p) of each species was calculated. The Eyring transition state theory with Wigner correction was used to calculate the main reaction The results show that the main product of CF_2 and CH_3CHO reaction is P2_F [CH_3CF-2CHO: insertion of CC bond in CH_3CHO, and the reaction The main products of reaction between CCI_2 and CBr_2 with CH_3CHO are P1_cl [Cl_2COCHCH_3: cyclization Ⅱ (1)] and P1B [Br_2COCHCH_3: cyclization Ⅲ (1)]. The reaction of I (2), Ⅱ (1) and Ⅲ (1) are 400 ~ 1300 K and 400 ~ 1000 K, respectively.