HAsS_2异构体结构与稳定性

The Structures and Stability of HAsS_2 Isomers

在 MP2 / 6-3 1 1 ++G(d,p)和 QCISD(t) / 6-3 1 1 ++G(3 df ,2 p) (单点 )水平下计算得到 9个异构体和1 0个过渡态的 HAs S2 体系势能面 .异构体 cis-HSAs S(E1 )的能量最低 ,其次是 trans-HSAs S(E2 )、具有As SS三元环的立体 HAs(S) S(Cs,E3 )和 HAs(S) S(C2 v,E4)结构的异构体 ,能量分别比 cis-HSAs S高 1 .46,60 .78和 93 .63 k J/ mol.根据体系的势能面 ,异构体 E1 ,E2 ,E3和 E4具有一定的动力学稳定性 .As H和 S2第一步反应产物将会异构化为具有较高动力学稳定性的异构体 E3 ,而 SH和 As S第一步反应产物将会异构化为 E1 .计算结果与 HNO2 ,HNS2 ,HPO2 ,HPS2 和 HAs O2

The potential energy surface (PES) of HAsS 2 system including nine isomers and ten transition states is inverstigated at MP2/6 311++G( d,p ) and QCISD(T)/6 311++G( 3df,2p )(single point) levels. On the PES, cis HSAsS(E1) is found to be thermodynamically and kinetically the most stable isomer followed by trans HSAsS(E2), stereo As S S three membered ring HAs(S)S( C 2v , E3), and HAs(S)S( C s , E4) at 1.46, 60.78, and 93.63 kJ/mol, respectively. Based on the PES, E1, E2, E3 and E4 are kinetically stable isomers, and should be experimentally observable. The products in the first step reaction of HAs with S 2 can isomerize into isomer E3 that has higher kinetic stability. The direct reaction products of SH with AsS will lead to the formation of isomer E1. The comparison of the calculated results with the PESs of HPO 2, HPS 2, HNO 2, HNS 2 and HAsO 2 that are analogs of HAsS 2 is investigated.