CAJ | 학술논문

采用量子化学方法,运用密度泛函理论(DFT)B3LYP方法,在6-311G*基组水平上,以2-氨基吡啶为起始反应物,全优化计算了亚硝酰阳离子NO~+对2-氨基吡啶中氨基进攻的重氮化反应及氟硼酸根阴离子BF_4~-对吡啶重氮正离子进攻的席曼反应的机理,搜索到整个反应过程中的过渡态结构,得到了反应路径并通过IRC验证,并对各反应中间体、过渡态和产物进行分子几何构型优化、振动频率分析和标准热力学函数计算.通过计算,搜索到的过渡态均为环状结构,与配位插入反应类似,利于原子间化学键的断裂及新键的形成;通过热力学及动力学计算,重氮化-席曼反应是剧烈的放热反应,与实验结果相吻合.
채용양자화학방법,운용밀도범함이론(DFT)B3LYP방법,재6-311G*기조수평상,이2-안기필정위기시반응물,전우화계산료아초선양리자NO~+대2-안기필정중안기진공적중담화반응급불붕산근음리자BF_4~-대필정중담정리자진공적석만반응적궤리,수색도정개반응과정중적과도태결구,득도료반응로경병통과IRC험증,병대각반응중간체、과도태화산물진행분자궤하구형우화、진동빈솔분석화표준열역학함수계산.통과계산,수색도적과도태균위배상결구,여배위삽입반응유사,리우원자간화학건적단렬급신건적형성;통과열역학급동역학계산,중담화-석만반응시극렬적방열반응,여실험결과상문합.
The mechanism of gas phase fluorination of 2-aminopyridine leading to 2-fluoropyridine was studied using the density functional theory (DFT) method at the B3LYP/6-311G* level. The pathways of both diazoreaction of 2-aminopyridine with nitrosyl cation (NO~+) and Schiemann reaction of diazo cation with fluoborate ion (BF_4~-) were calculated without any assumption. The geometrical parameters of transition states (TS) and intermediates (IM) were optimized. Intrinsic reaction coordinate (IRC) was also performed to obtain further credible features. Frequency analyses of all the stationary points were calculated at the same basis sets. The calculation results revealed that the transition states have ring structure, similar to coordinated-inserted reaction, which are propitious to the rupture and formation of chemical bonds. The reaction was proved to be an exothermic reaction by dynamic and thermodynamic which agrees with experimental results.