5-硝基-1-氢-四唑分子热分解反应机理的密度泛函理论研究

The Mechanisms of Thermal Decomposition of 5-Nitro-1-hydrogen- tetrazole: A Density Function Theory Study

利用密度泛函理论研究了 5 硝基 1 氢 四唑分子热分解的反应机理 .首先用B3LYP/ 6 31G(d)方法优化反应中反应物、过渡态、中间体以及产物的几何构型 ,通过振动分析得到零点能校正值并确认反应的过渡态 .此外 ,对各个构型作了CCSD(T) / 6 31G(d ,p)水平下的单点计算 .报道了三条可能的反应途径 ,即直接开环途径和质子转移途径 :其中N(1)—N(2 )键断裂直接开环的机理与文献报道一致 ;而涉及质子转移的反应途径则是一个新的发现 ;另一条关于N(4 )—C(5 )键断裂直接开环的途径由于能垒较高 ,因此发生的几率较小 .

The mechanisms dealing with the thermal decomposition of 5-nitro-1-hydrogen-tetrazole are studied by density function theory. The geometries of the reactants, transition states, intermediates and products are optimized at the B3LYP/6-31G(d) level. The corresponding vibrational frequencies are calculated to take account of the zero-point vibrational energy (ZPE) and to identify the transition structures. The single point calculations are obtained at the CCSD(T)/6-31G(d, p) level. Three possible reaction channels are shown, including direct ring rupture channels and proton transfer channel. The one of N(1)-N(2) bond-breaking ring rupture channel agrees with the result reported before. The one dealing with proton transfer shows a new feature of the titled compound's thermal decomposition. The other one of N W-C (5) bond-breaking ring rupture has the highest activation barrier of all the three channels and therefore it occurs less often than the former two.