取代基对卟吩结构和性质的影响

运用密度泛函理论(DFT) B3LYP/6-31G(d, p)方法, 对卟吩及其被取代基—CH=CH₂、—COCH₃、—CHOHCH₃、—CHNH₂CH₃或—CHSHCH₃所修饰后的分子构型进行了优化. 同时, 对其电子吸收光谱与核磁共振氢谱也进行了量化计算. 结果表明, 这些取代基有着各自不同的空间构象, 对卟吩环的整体结构没有很大的扰动. 然而, 它们重新调整了卟吩环中原子电荷的分布, 改变了前线分子轨道(LUMO-HOMO)能隙, 结果导致卟吩的吸收光谱与¹H NMR均发生了相应的改变.

Effects of Substitution on the Structure and Property of Porphin

The molecular geometries of porphin and those modified with —CH=CH2, —COCH3, —CHOHCH₃, —CHNH₂CH₃, or —CHSHCH₃ groups were optimized at the B3LYP/6-31G (d, p) level of density functional theory (DFT). At the same time, their absorption spectra and ¹H NMR were also calculated. The results illustrated that these substitution groups had differential spatial positions and did not disturb the structure of porphin extremely. Meanwhile, they have re-adjusted the contribution of atomic charges of porphin and then have changed the LUMO-HOMO energy gaps of porphin. As a result, the absorption spectra and 1H NMR were changed accordingly.