磷杂硫烯酮及相关分子的结构和气相酸性的理论研究

Theoretical Studies of the Structure and Gas-Phase Acidity of Phosphathioketene and Related Molecules

使用Gaussian 98量子化学计算程序包中的HF法、密度泛理论(B3LYP)和MP2法,在6 311++G(d,p)和AUG CC PVTZ基组水平下,对磷杂硫烯酮及其相关分子进行了全优化几何构型的量子化学计算.计算结果表明:磷杂硫烯酮为累积双烯结构,其异构体有C≡P三键,二者的去质子负离子为累积双烯结构,中性分子和相关负离子都具有弯曲几何构型.计算的气相酸性表明;磷杂硫烯酮比异构体(Ⅱ)较难去质子化.

Phosphathioketene and related molecules have been calculated by several methods of quanutum chemistry in Ganssian-98 programme. The optimized grometries of molecules and gas-phase acidity (free energy of deprotonation, ΔG^0) of phosphathioketene and isomer are obtained at the SCF?B3LYP(DFT) and MP_2 levels using 6-311++G(d,p) and AUG-CC-PVTZ basis sets. The results of calculations show that phosphathioketene presents cumulative double bonds, isomer presents C≡P triple bonds, all of anion of deprotonation presents cumulative double bonds, the molecules and anions have a trans-bent geometries. Compared with phosphathioketene,calculations of the gas-phase acidity predict a sight increasing of deprotonation in isomer(Ⅱ).