气相中Ir＋循环催化N2O与CO反应机理的理论研究

采用密度泛函UB3LYP方法和Stuttgart赝势基组, 计算研究了气相中循环催化N2O ＋CO →N2 ＋CO2 反应的微观机理. 通过对相关物种亲氧性的计算, 证明了Ir＋循环催化作用在热力学上是可行的. 不同自旋态反应势能面的计算结果表明, 循环催化的两步反应均为自旋禁阻反应, 各存在不同自旋态势能面的交叉, 并运用Yoshizawa的内禀坐标单点垂直激发计算的方法找出了势能面交叉点; 两步反应均为放热反应, 总放热量为358.9 kJ•mol－1.

Theoretical Study on the Gas-Phase Mechanism of the Reaction of N2O with CO Circularly Catalyzed by Ir+

The mechanism of the cyclic reaction N2O ＋CO →N2 ＋CO2 catalyzed by Ir＋ has been investigated on both triplet and quintet potential energy surfaces (PES). The reactions were studied by the UB3LYP density functional method and the Stuttgart pseudopotentials. The O-atom affinities of the correlative species were calculated, which testified that the cyclic, catalytic function of Ir＋ was thermodynamically allowed. Moreover, the calculated results of different spin PES show that the reaction proceeds in a two-step manner and spin crossing between different PES occurs. The involved crossing between the PES has been discussed by means of the intrinsic reaction coordinate approach used by Yoshizawa et al., and the crossing points were located. Furthermore, both steps of the reaction are exothermic and the overall exothermicity is 358.9 kJ•mol－1.