单取代叠氮化合物异构化反应的从头计算研究

Ab initio Study on the Tautomerisms of Monosubstituted Tetrazoles

在MP2 /6-3 1G和MP2 /6-3 1 1G水平上 ,对单取代叠氮化合物R_N3(R =H ,CH3和CHO)的环状和链状异构体的相对稳定性及其异构反应进行了从头计算研究。结果表明 ,三种目标叠氮化合物的链状异构体比环状异构体稳定 ,由环状异构体异构成链状异构体的反应有较低的活化能。

Ab initio method with MP2/6_31G and MP2/6_311G have been applied to study the isomeric reactions of monosubstituted tetrazoles.The results obtained show that:(1)the chain isomers[B]are more stable than the cyclic isomers[A],the energy differences between[A] and [B]are Δ E (= E [B] - E [A] =-225.834 76/MP2/6_31G(-219.530 42/MP2/6_311G)( R =H),-209.319 59/MP2/6-31G (-203.216 89/MP2/6_311G)( R =CH 3) and -235.009 03/MP2/6_31G(-234.165 98/MP2/6_311G)( R =CHO)kJ·mol -1 ,respectively;(2)the activation energies E a(= E TS - E [A] )of these isomeric reactions are 18.485 60/MP2/6_31G(27.265 00/MP2/6_311G)( R =H),10.817 31/MP2/6_31G(21.996 41/MP2/6-311G)( R =CH 3) and 27.759 38/MP2/6_31G(38.239 58/MP2/6_311G)( R =CHO)kJ·mol -1 ,respectively.