【作者】 邵怿；

【导师】 倪良；

【作者基本信息】 江苏大学 ， 应用化学， 2009， 硕士

【摘要】 硫脲衍生物因具有特殊的功能结构,使其在生物医学、工农业生产、日常生活及其它学科的各个领域都有非常重要的用途,对化学学科的各个分支及一些边缘学科也有很重要的作用。但是对于硫脲衍生物与其他物质反应的理论研究还很少,热力学参数的数据还不完善。量子化学方法可应用于分子热力学、光谱和反应动力学性质的研究。因此利用量子化学研究硫脲衍生物与醛、酮加成一缩合反应系统中反应物和产物的电子结构、光谱性质和热力学性质,将对此类反应活性、可行性和外部条件的控制从理论上得到较好的预示,具有重要的理论意义和实际应用价值。本论文主要研究内容为:(1)对香草醛和氨基硫脲亲核加成-缩合反应体系的反应物和生成物,用量子化学密度泛函方法在B3LYP/6-31G水平上进行几何构型全优化,将从获得的香草醛分子中主要原子的Mulliken净电荷,推测该化合物具有较高的亲核加成反应活性。对优化后的构型进行振动分析,得到不同温度下反应物和生成物的热力学性质,据此计算相应温度下该反应的焓变、吉布斯自由能变和平衡常数。在此基础上采用含时密度泛函方法(TD-DFT)计算分子激发态的电子跃迁能,得到对应激发态的吸收波长。(2)对氨基硫脲和水杨醛亲核加成-缩合反应体系的反应物和生成物,用量子化学密度泛函方法在B3LYP/6-31G水平上进行几何构型全优化,将从获得的水杨醛分子中主要原子的Mulliken净电荷,推测该化合物具有较高的亲核加成反应活性。对优化后的构型进行振动分析,得到不同温度下反应物和生成物的热力学性质,据此计算相应温度下该反应的焓变、吉布斯自由能变和平衡常数。在此基础上采用含时密度泛函方法(TD-DFT)计算分子激发态的电子跃迁能,得到对应激发态的吸收波长。(3)对氨基硫脲和4-氯查尔酮亲核加成-缩合反应体系的反应物和生成物,用量子化学密度泛函方法在B3LYP/6-31G水平上进行几何构型全优化,将从获得的4-氯查尔酮分子中主要原子的Mulliken净电荷,可以推测该化合物具有较高的亲核加成反应活性。对优化后的构型进行振动分析,得到不同温度下反应物和生成物的热力学性质,据此计算相应温度下该反应的焓变、吉布斯自由能变和平衡常数。在此基础上采用含时密度泛函方法(TD-DFT)计算分子激发态的电子跃迁能,得到对应激发态的吸收波长。更多还原

【Abstract】 Thiourea derivatives have been playing important roles in biology, medicine,daily life,industrial and agricultural production because of their special functional structure.They have potential applications in various branches of chemistry and some marginal subjects.However,less theoretical researches have been carried on the reaction between thiourea derivatives and other substances,while thermodynamic parameters of the reactions are still faultiness.Quantum chemical methods can be applied to investigate molecular thermodynamics,spectroscopy and reaction kinetics.Recently,intense researches of quantum chemistry have been focused on the electronic structure,spectroscopic properties and thermodynamic properties of the reactants and products through addition -condensation reaction of thiourea derivatives with aldehydes and ketones,which may play important roles in theoretical researches and practical applications.The major research contents are as follows:（1） For reactants and products in nucleophilic addition-condensation reaction of vanillin with thiosemicarbazide,their geometry configurations were optimized by means of quantum chemistry DFT/B3LYP/6-31G. From the Mulliken atomic net charge of main elements,as well as E_HOMO and E_LUMO data of vanillin,it can be assumed that the compound has a higher activity of nucleophilic addition reaction.The thermodynamic properties of reactants and products were obtained via vibrational analyses for all optimal geometries.The changes of enthalpy and Gibbs free energy,and standard equilibrium constants were calculated.Then,by calculating the energies of electron transitions at excited states of molecule,the UV-Vis data of excited states were obtained.（2）For reactants and products in nucleophilic addition-condensation reaction of thiosemicarbazide with salicylaldehyde,their geometry configurations were optimized by means of quantum chemistry DFT/B3LYP/6-31G.From the Mulliken atomic net charge of main elements,as well as E_HOMO and E_LUMO data of salicylaldehyde,it can be assumed that the compound has a higher activity of nucleophilic addition reaction.The thermodynamic properties of reactants and products were obtained via vibrational analyses for all optimal geometries.The changes of enthalpy changes and Gibbs free energy,and standard equilibrium constants were calculated.Then,by calculating the energies of electron transitions at excited states of molecule,the UV-Vis data of excited states were obtained.（3） For reactants and products in nucleophilic addition-condensation reaction of thiosemicarbazide with 4-chlorochalcone,their geometry configurations were optimized by means of quantum chemistry DFT/B3LYP/6-31G.From the Mulliken atomic net charge of main elements,as well as E_HOMO and E_LUMO data of 4-chlorochalcone,it can be assumed that the compound has a higher activity of nucleophilic addition reaction.The thermodynamic properties of reactants and products were obtained via vibrational analyses for all optimal geometries. The changes of enthalpy changes and Gibbs free energy,and standard equilibrium constants were calculated.Then,by calculating the energies of electron transitions at excited states of molecule,the UV-Vis data of excited states were obtained.更多还原