Chemistry Department, College of Sciences, Shiraz University, Shiraz, 71454, Iran.
Chemistry Department, College of Sciences, Shiraz University, Shiraz, 71454, Iran.
J Mol Graph Model. 2020 Sep;99:107643. doi: 10.1016/j.jmgm.2020.107643. Epub 2020 May 15.
In the present work, the total non-Lewis structure (TNLS) is introduced for describing the stability and reactivity of linear and angular polyacenes. TNLS of a molecule is derived from the natural bond orbital theory representing the antibonding orbitals and/or electron delocalization of π orbitals. To verify this application, we obtained the TNLS values of thirteen linear and angular polyacenes and evaluated with other quantitative aromaticity probes based on reactivities, energetics, geometrics, and magnetic properties. Our results show that there is a remarkable second-order polynomial correlation between TNLS and seven popular global measures of aromaticity including hardness, resonance energy, aromatic stabilization energy, harmonic oscillator measure of aromaticity, magnetic susceptibility exaltation, global magnetic characteristics, and mean polarizability. By increasing the TNLS values of the systems the reactivity increases and stability decreases. It is worth mentioning that the angular polyacenes produce less TNLS values than the linear systems with the same number of benzene rings. Therefore, it can be stated that TNLS values confirmed with Clar's rule which in general prove the angular polyacenes are more stable than linear ones.
在本工作中，引入了总非路易斯结构（TNLS）来描述线型和角型聚并苯的稳定性和反应性。分子的 TNLS 源自自然键轨道理论，代表了反键轨道和/或π轨道的电子离域。为了验证这种应用，我们得到了十三种线型和角型聚并苯的 TNLS 值，并基于反应性、能学、几何形状和磁性质，用其他定量芳香性探针进行了评估。我们的结果表明，TNLS 与七种流行的全局芳香性度量之间存在显著的二阶多项式相关性，包括硬度、共振能、芳香稳定能、谐振子芳香性度量、磁化率升高、全局磁性质和平均极化率。随着系统的 TNLS 值的增加，反应性增加，稳定性降低。值得一提的是，具有相同苯环数的角型聚并苯产生的 TNLS 值小于线型体系。因此，可以说 TNLS 值证实了 Clar 规则，通常证明角型聚并苯比线型聚并苯更稳定。
