Ren Fu-de, Cao Duan-lin, Shi Wen-jing, You Min, Li Man
College of Chemical Engineering and Environment, North University of China, Taiyuan, 030051, China,
J Mol Model. 2015 Jun;21(6):145. doi: 10.1007/s00894-015-2699-9. Epub 2015 May 20.
The effects of an external electric field on the C/N-NO2 bond with C/N-H and N-O bonds in CH3NO2 or NH2NO2 were compared using the DFT-B3LYP and MP2 methods with the 6-311++G(2d,p) and aug-cc-pVTZ basis sets. The results show that such fields have a minor effect on the C-N or C-H bond but a major effect on the N-O bond in CH3NO2, while in NH2NO2 electric fields affect the N-N bond greatly but the N-O or N-H bond only slightly. Thus, in CH3NO2, oxygen transfer or unimolecular isomerization to methyl nitrite might precede breaking of the C-N bond in the initial stages of decomposition, and the N-O bond could be the trigger bond in electric fields. In NH2NO2, however, N-N bond rupture may be preferential in an electric field and, consequently, the N-N bond might always be the real trigger bond. Atoms in molecules and natural bond orbital delocalization analyses, together with examination of shifts in electron density and frequencies support the above viewpoints. Forty-eight good linear correlations were found along the different field orientations at different levels of theory, including those between field strength (E) and changes in N-O/N-N bond length (ΔR N-O/N-N), ρ (N-O/N-N) values [Δρ (N-O/N-N), or stretching frequencies of the N-O/N-N bond (ΔυN-O/N-N). Graphical Abstract External electric fields have a major effect on the N-O or N-N bond inCH3NO2 or NH2NO2 , leading to a possible N-O trigger bond inCH3NO2 or a real N-N trigger bond in NH2NO2 in an electric field.
使用密度泛函理论（DFT）-B3LYP方法以及二阶微扰理论（MP2）方法，结合6-311++G(2d,p)和aug-cc-pVTZ基组，比较了外部电场对CH3NO2或NH2NO2中C/N-NO2键与C/N-H键和N-O键的影响。结果表明，此类电场对CH3NO2中的C-N或C-H键影响较小，但对N-O键影响较大；而在NH2NO2中，电场对N-N键影响很大，但对N-O或N-H键影响较小。因此，在CH3NO2中，在分解初始阶段，氧转移或单分子异构化为亚硝酸甲酯可能先于C-N键断裂，并且N-O键可能是电场中的触发键。然而，在NH2NO2中，N-N键在电场中可能优先断裂，因此，N-N键可能始终是真正的触发键。分子中的原子和自然键轨道离域分析，以及电子密度和频率变化的考察支持了上述观点。在不同理论水平下，沿不同场取向发现了48个良好的线性相关性，包括场强（E）与N-O/N-N键长变化（ΔR N-O/N-N）、ρ（N-O/N-N）值[Δρ（N-O/N-N）]或N-O/N-N键的拉伸频率（ΔυN-O/N-N）之间的相关性。图形摘要 外部电场对CH3NO2或NH2NO2中的N-O或N-N键有重大影响，导致在电场中CH3NO2中可能存在N-O触发键或NH2NO2中存在真正的N-N触发键。
