量子化学计算方法研究苯甲酰丙酮与氨基硫脲的缩合反应机理  

Study of the condensation reaction mechanism between benzoylacetone and thiosemicarbazide using quantum chemistry calculation method

作　　者：朱金花 朱华玲[2] 张欣[3] 石军[2] 尉震[2] 

机构地区：[1]山西省气象服务中心,山西太原030002 [2]天津农学院基础科学系,天津300384 [3]天津师范大学化学学院,天津300387

出　　处：《计算机与应用化学》2013年第9期1084-1086,共3页Computers and Applied Chemistry

基　　金：山西省气象局资助项目(SXKQNFW20102111)

摘　　要：本文通过对苯甲酰丙酮与氨基硫脲缩合反应产物的合成和表征,确定了生成物的结构构型。对苯甲酰丙酮与氨基硫脲缩合反应过程中可能存在的加成反应、脱水反应和环合反应,首次采用量子化学计算方法在RB3LYP/6-31G的水平上研究了反应物、产物、中间体复合物和过渡态的优化构型和振动频率,频率分析确定了各中间体稳定性和过渡态的真实性,对每个过渡态均进行内禀反应坐标(IRC)计算以确认它连接着特定的反应物和产物。在RB3LYP/6-311G(2d,2p)的水平上得到了各驻点的能量,分析了苯甲酰丙酮与氨基硫脲的缩合反应途径和机理。机理结果分析表明苯甲酰丙酮与氨基硫脲发生反应时基本分4步进行,氨基硫脲的远端氨基加成到苯甲酰丙酮的远端羰基上生成TM1,TM1进而脱水生成稳定的中间产物PC1,然后PC1发生构象异构化生成TM2,最后氨基硫脲的仲氨氮原子加成到苯甲酰丙酮的近端羰基上形成一个稳定的五元环。The product compound of the reaction between benzoylacetone and thiosemicarbazide was synthesized and characterized by IR and X-ray diffraction. To the possible addition reaction, dehydration reaction and cyclization reaction in the process of the reaction between benzoylacetone and thiosemicarbazide, the DFT/RB3LYP/6-31G level was firstly adopted to study the optimization configuration and vibration frequency of the reactants and products, intermediates complex and transition state, The data of the frequency of the intermediate and the transition state ensures the stability of the intermediate and the reality of the transition state, intrinsic reaction coordinate （IRC） calculation was run to confirm that each transition state is connected to a specific reactants and products. DFT/RB3LYP/6-311G （2d, 2p） level was also adopted to study the energy of the stagnation points, the way and mechanism of the reaction between benzoylacetone and thiosemicarbazide was studied completely. Results show that there are four steps in the reaction of benzoyl acetone and thiosemicarbazide. At first, the distal amino group of thiosemicarbazide is added to the distal carbonyl group of benzoyl acetone which forms TM1. Secondly, a dehydration reaction occurs in TM1 and generates a stable intermediate PC1. Thirdly, a conformational isomerization occurs in PC1 which forms TM2. Finally, the second amino group of thiosemicarbazide is added to the proximal carbonyl group of benzoyl acetone forming a stable five-member ring.

关 键 词：苯甲酰丙酮 氨基硫脲 合成 表征 反应机理 

分 类 号：TQ015.9[化学工程] TP391.9[自动化与计算机技术—计算机应用技术]