The geometrical structures of a series of thioindigo compounds have been optimized by using ab initio HF and DFT-B3LYP method.Subsequently,Time-dependent density functional theory(TD-DFT) and semi-empirical ZINDO appr...The geometrical structures of a series of thioindigo compounds have been optimized by using ab initio HF and DFT-B3LYP method.Subsequently,Time-dependent density functional theory(TD-DFT) and semi-empirical ZINDO approach have been employed to calculated electronic absorption spectrum of thioindigo.The effect of the change of electron-donating group and the extension of chromophore on the electronic spectrum was investigated,and good results were achieved compared with the experimental data.It was shown that,absorption band of chromophore suffers bathochromic shift when electron-donating capability was increased and minor hypsochromic shift when the chromophore was extended.In addition,the frontier molecular orbital composition was analysed by natural population analysis,which indicated that the main absorption spectrum originate from the π→π*electronic transition among the molecular orbitals.展开更多
以氨基甲磺酸为原料,经烷基化、环合、成盐等反应合成头孢尼西钠的重要中间体1-磺酸甲基四氮唑-5-硫醇双钠盐。将微波辐射技术应用到烷基化反应中,探讨了微波辐射功率、时间、溶剂对反应的影响,最佳反应条件为:以乙醇和水为溶剂,微波辐...以氨基甲磺酸为原料,经烷基化、环合、成盐等反应合成头孢尼西钠的重要中间体1-磺酸甲基四氮唑-5-硫醇双钠盐。将微波辐射技术应用到烷基化反应中,探讨了微波辐射功率、时间、溶剂对反应的影响,最佳反应条件为:以乙醇和水为溶剂,微波辐射功率250 W,辐射8min,磺甲基二硫代氨基甲酸乙酯钾盐的收率84.0%;用乙醇钠成盐,1-磺酸甲基四氮唑-5-硫醇双钠盐收率88.3%。产物总收率68.1%(以氨基甲磺酸计),纯度99.3%(HPLC),产物结构经IR、1 H NMR、MS和元素分析进行了确证。展开更多
文摘The geometrical structures of a series of thioindigo compounds have been optimized by using ab initio HF and DFT-B3LYP method.Subsequently,Time-dependent density functional theory(TD-DFT) and semi-empirical ZINDO approach have been employed to calculated electronic absorption spectrum of thioindigo.The effect of the change of electron-donating group and the extension of chromophore on the electronic spectrum was investigated,and good results were achieved compared with the experimental data.It was shown that,absorption band of chromophore suffers bathochromic shift when electron-donating capability was increased and minor hypsochromic shift when the chromophore was extended.In addition,the frontier molecular orbital composition was analysed by natural population analysis,which indicated that the main absorption spectrum originate from the π→π*electronic transition among the molecular orbitals.
文摘以氨基甲磺酸为原料,经烷基化、环合、成盐等反应合成头孢尼西钠的重要中间体1-磺酸甲基四氮唑-5-硫醇双钠盐。将微波辐射技术应用到烷基化反应中,探讨了微波辐射功率、时间、溶剂对反应的影响,最佳反应条件为:以乙醇和水为溶剂,微波辐射功率250 W,辐射8min,磺甲基二硫代氨基甲酸乙酯钾盐的收率84.0%;用乙醇钠成盐,1-磺酸甲基四氮唑-5-硫醇双钠盐收率88.3%。产物总收率68.1%(以氨基甲磺酸计),纯度99.3%(HPLC),产物结构经IR、1 H NMR、MS和元素分析进行了确证。
