吲哚咔唑类异构体芳香性的研究  

A Study on the aromaticity of indolocarbazole isomers

作　　者：艾合买提·沙塔尔[1] 阿布力克木·克热木[1] SHATAER Aihemai-ti;KERIM Abli-kim(School of Chemical Engineering and Technology,Xinjiang University,Urumqi 830046,China)

机构地区：[1]新疆大学化工学院,新疆乌鲁木齐830046

出　　处：《分子科学学报》2023年第4期318-326,共9页Journal of Molecular Science

基　　金：国家自然科学基金资助项目(21662033)。

摘　　要：分别采用拓扑共振能(ETR)和环电流(RC)方法对吲哚咔唑类化合物的全局芳香性进行了研究.根据ETR结果,预测所有化合物都具有芳香性.分别用键共振能(BRE)和回路共振能(CRE)方法揭示了它们的局部芳香性.BRE和CRE研究结果表明,在吲哚咔唑类化合物中,由于六元环内电子的离域化程度比五元环内电子的离域化程度强,因此六元环比五元环表现出较强的局部芳香性.此外,外部六元环比中间六元环具有较强的局部芳香性.计算得到的RC结果表明,所有化合物都产生反磁性环电流,化合物产生的反磁性RC强度与它们的1H NMR化学位移之间具有很好的一致性.The phenomenon of aromaticity,is of particular interest in contemporary chemistry.Numerous attempts have been made to generalize the classical rule of Hückel to polycyclic condensed molecules.In this paper,the relative aromaticity of indole(1),carbazole(2),and five indolocarbazole isomers(3-7)has been examined using E_(TR)(topological resonance energy),E_(TR,pct)(percentage topological resonance energy),and MRE(magnetic resonance energy)methods.The impact of nitrogen atoms on the aromaticity of the compounds is discussed.According to the E_(TR)results,all the isomers are predicted to be aromatic with positive E_(TR)s and positive MREs.An excellent correlation is found between the E_(TR)and MRE with a correlation coefficient of 0.9998.This indicates that not only E_(TR)but also MRE can be used as a reliable indicator of global aromaticity.According to the E_(TR),E_(TR,pct),and MRE indices,it was found that increases of benzo-annelation to the molecules 1 and 2 have little effect on the relative degree of the global aromaticity of these isomers.The local aromaticity was studied using bond resonance energy(BRE)and circuit resonance energy(CRE)indices and our local aromaticity results of 1 and 2 are compared with the other aromaticity indices as reported in the literature.Our BRE and CRE results show that all of these compounds are primarily stabilized by the 6πelectron conjugated system,none of these compounds are stabilized by their peripheralπ-electronic structure.The magnitude of local aromaticity is closely related with the uniformity of charge distribution in the molecule.The BRE and CRE results show that the degree of delocalization of electrons in the six-membered ring is stronger than that in the five-membered ring,so the six-membered ring shows stronger local aromaticity than the five-membered ring in the same molecule.In addition,the outer six-membered ring has a stronger local aromaticity than the inner six-membered ring.The ring current(RC)analyses were made using the Hückel-London model.RC results r

关 键 词：吲哚咔唑 共振能 全局芳香性 局部芳香性 环电流 

分 类 号：O625[理学—有机化学]