三重态类硅烯HB＝SiLiF的结构及其与R—H(R=F,OH,NH_2)的插入反应

用密度泛函理论(DFT)和二次组态相互作用(QCISD)方法研究了三重态类硅烯HB=SiLiF的结构及其与RH(R=F,OH,NH2)的插入反应.计算结果表明,类硅烯HB=SiLiF有三种平衡构型,其中四元环构型能量最低,是其存在的主要构型.HB=SiLiF与HF,H2O和NH3发生插入反应的机理相同.QCISD/6-311++G(d,p)//B3LYP/6-311+G(d,p)计算的三个反应的势垒分别为124.85,140.67和148.16kJ·mol-1,反应热分别为-2.22,20.08和23.22kJ·mol-1.相同条件下发生插入反应时,反应活性都是H—FH—OHH—NH2.

Structures of the Triplet Silylenoid HB=SiLiF and Its Insertion Reactions with R-H (R=F, OH, NH2)

Density functional theory (DFT) and quadratic configuration interaction with single and double excitations (QCISD) methods were used to investigate the geometries of the triplet silylenoid HB=SiLiF as well as its insertion reactions with RH (R=F, OH, NH₂). The calculated results indicated that HB=SiLiF has three equilibrium structures wherein the four-membered ring structure had the lowest energy and it was the most stable structure. The mechanisms of the insertion reactions for HB=SiLiF with HF, H₂O, and NH₃ were identical. The QCISD/6-311++G(d,p)//B3LYP/ 6-311+G(d,p) calculated potential energy barriers of the three reactions were 124.85, 140.67, and 148.16 kJ·mol^-1, and the reaction heats for the three reactions were -2.22, 20.08, and 23.22 kJ·mol ^-1, respectively. Under the same conditions, the insertion reactions should occur easily according to the following order: H—F>H—OH>H—NH₂.