1,1′-二羟基-5,5′-联四唑合成机理的理论计算

Theoretical Calculation on the Synthetic Mechanism of 1,1′-Dihydroxy-5,5′-bitetrazole

为了研究由二叠氮基乙二肟(DAzGO)合成1,1′-二羟基-5,5′-联四唑(H_2DHBT)的反应机理,采用密度泛函理论(DFT),在B3LYP/6-31G(d)基组水平上计算了酸性条件下DAzGO分子成环反应的反应物、过渡态和产物结构,获得反应能垒。结果表明,DAzGO分子的成环为两步成环的亲电反应,其中第一个基元反应是决速步,反应能垒为86.94kJ/mol;氢离子和水分子的存在将反应能垒降低了30.46kJ/mol,氢离子和水分子可以促进成环反应。DAzGO的成环反应在丙酮、水、乙醚中的决速步能垒分别为87.03、90.08、72.59kJ/mol;溶剂的极性越小,对DA_2GO分子成环反应的促进作用越大,乙醚为最佳反应溶剂。

To study the synthetic mechanism of 1,1′-dihydroxy-5,5′-bitetrazole(H2DHBT)from diazidoglyoxime(DAzGO),the density functional theory(DFT)method was employed to calculate the reactants,transition state and product structure of the cyclization reaction of DAzGO molecule under acidic conditions were calculated by density functional theory(DFT)at the level of B3LYP/6-31G(d)basis set,and the reaction energy barrier was obtained.The results show that the cyclization reaction of DAzGO molecule is a two-step cyclization electrophilic reaction.The first elementary reaction is rate-determining step,the reaction energy barrier is 86.94kJ/mol.The presence of hydrogen ions and water molecules reduces the reaction energy barrier by 30.46kJ/mol,the hydrogen ions and water molecules can promote the cyclization reaction.The energy barriers of rate-determining step for the cyclization reaction of DAzGO in acetone,water and ether are 87.03,90.08 and 72.59kJ/mol.The smaller of the polarity of solvent,the greater of promotion to cyclization reaction of DAzGO molecule,and ether is the best reaction solvent.