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采用密度泛函理论(DFT)方法,在B3LYP/6-31++G(d,p)水平上研究了4-亚芳基亚氨基-1,2,4-三唑-3(2H)-酮及其类似物的气相热分解反应.从热力学性质、几何结构参数、自然电荷分布、温度效应等角度探讨不同取代基对标题物热分解反应的影响.结果表明:R(R=H,CH_2CH2_CN)取代基对反应影响很小;而苯环上Y(Y=MeO,Me,H,Cl和NO_2)取代基对活化自由能(△G~≠)、键长(△R~≠)、键角(△α~≠)和自然电荷(△q~≠)变化的影响与Hammet常数(σ)呈现线性关系△P~≠=pσ+C(P=G,R,α和q,r>0.95).给电子基团使得相应的活化自由能降低,键长变短,键角变大,自然电荷增加;吸电子反之.
The effects of 4-aryleneimino-1,2,4-triazol-3 (2H) - dihydropyridines on the level of B3LYP / 6-31 ++ G (d, p) were studied by density functional theory (DFT) The effects of different substituents on the thermal decomposition reaction of title compounds were discussed from the aspects of thermodynamic properties, geometrical structure parameters, natural charge distribution and temperature effects. The results showed that R (R = H, CH 2 CH 2 CN ) Substituents have little effect on the reaction; while the substituents of Y (Y = MeO, Me, H, Cl and NO 2) on the benzene ring have no significant influence on the activation energy (△ G ~ ≠), bond length The influence of the change of angle (△ α ~ ≠) and natural charge (△ q ~ ≠) shows a linear relation with Hammet constant (σ) △ P ~ ≠ = pσ + C (P = G, R, α and q, r> 0.95 The electron donating group makes the corresponding free energy of activation lower, the bond length becomes shorter, the bond angle becomes larger and the natural charge increases, and the electron withdrawing conversely.