硫化磷的构型稳定性

Configuration Stabilities of Phosphorus Sulfides

在RHF/6-311++G(3d)水平上,优化分子的几何构型,以高精度积分网格,计算MPW1PW91/6-311++G(3d)总能和相对稳定能.通过相对能量值的对比,系统地研究了3种硫化磷分子β-P4S4,β-P4S5和γ-P4S6,以及结合端点硫(μ1-S)原子形成的系列同分异构体的稳定性,从中找到实验分子构型与稳定性的联系.同时,根据分子的总能、稳定化能和P—(μ1-S)键能的相对大小,对系列同分异构体中相对稳定的、而又未知的分子构型进行理论推测.通过对比理论上稳定的分子和实验已发现的分子,结果是实验分子的稳定性无一例外地得到理论计算的证实,预测了可能合成的其它稳定分子构型α1-P4S6,α1-P4S7,γ-P4S7,γ-P4S8和γ-P4S9,并讨论了结构因素对分子构型稳定性的影响和成键规律.

The optimized geometries of phosphorus sulfides accorded with the experimental structures have been acquired at RHF/6-311 ＋ ＋G（3d） level. The stabilities of a series of isomers in which P atoms are bonded with terminal sulfur atoms （μ1-S） in three kinds of phosphorus sulfides were studied systematically at MPW1PW91/6-311＋ ＋G（3d） level and, the relations to the molecular configurations were deduced. By comparing the total energy, the relative stabilization energy and the P-（μ1-S） bond energy of phosphorus sulfides, it is concluded that a stable molecular structure should possess those of lower values simultaneously. In addition, the configurations of molecules unknown in the experiments but relative stable comparative to their isomers have been predicted theoretically. The stabilities of the experimental molecules are proved by RHF and MPW1PW91 calculations through comparing them with their isomers. The imaginable molecular structures in the future synthesis, such as a1-P4S6, al-P4S7, γ-P4S7, γ-P4S8 and γ-P4S9 can be resolved because both the structures and the front orbital of them favor the stabilities. The influence of struc- tures on the molecular stabilities and the rules of chemical bonding have been discussed.