几种取代苯硫酚分子结构与振动光谱的理论研究

Theoretical Study of Geometrical Structures and Properties of Several Replaced Mercapto Molecules

采用密度泛函理论(density functional theory,DFT)中的杂化密度泛函B3LYP方法,在6-311++G**基组水平上对几种取代苯硫酚分子的构型进行了几何优化,得出了它们的最稳定构型并对其能级差、核独立化学位移、极化率和振动光谱进行了理论计算。研究结果表明,4-巯基吡啶(4-MPY)、4-巯基苯甲酸(4-MBA)和4-巯基苯胺(PATP)均为平面构型,1,4对巯基苯(BDT)中S-H键与苯环平面的夹角为20.2°,4-甲基巯基苯(4-MBT)中S-H键与苯环平面的夹角为39.6°。几种分子都具有很强的芳香性和较大的极化率值。5种分子的极化率张量平均值大小顺序为BDT>4-MBT>4-MBA>4-MPY>PATP,极化率的各向异性不变量变化趋势为4-MBA>4-MBT>BDT>PATP>4-MPY。

The geometrical structures of several Raman probe molecules were optimized using density functional theory （DFT） of the hybrid density functional BSLYP method and 6-311 ＋ ＋G＊＊ basis set. Their energy gap, nucleus independent chemical shift （NICS）, polarizability and vibration spectrum were studied. The theoretical results showed that： 4 MPY, MBA and PATP had planar structures, the angle of BDT between S-H and benzene ring plane was 20.2°, and the 4-MBT was 39.6° ; they all have a strong aroma and a large value of polarization. The order of the average of molecular hyperpolarizability tensor was BDT〉4- MBT〉4 MBA〉4-MPY〉PATP, and the trends of polarizability anisotropy invariant were 4-MBA〉4-MBT〉BDT〉PATP2〉 4-MPY.