Computational Studies on the Structures of Nanographenes with Various Edge Functionalities
Computational Studies on the Structures of Nanographenes with Various Edge Functionalities
复制标题
具有各种边缘功能的纳米石墨烯结构的计算研究
DOI：
10.1002/cphc.202200465
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发表时间：
2022
期刊：
影响因子：
2.9
通讯作者：
Takeharu Haino
中科院分区：
文献类型：
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作者：
Shusaku Takahashi;Ryo Sekiya;Takeharu Haino
计算研究经常对端氢纳米石墨烯（NGs）进行。然而，这些结构与从实验观察中推断出来的结构相去甚远，实验观察表明，扶手椅边缘上有两个羧基占主导地位。我们对由C42、C60、C78、C96、C142和c174碳原子组成的NGs进行了计算研究，这些碳原子具有氢、羧基和n -甲基亚胺末端的扶手椅边缘。DFT计算得到了扭曲的基面和类似的HOMO - LUMO间隙，表明边缘氧化和功能化对电子结构的影响不大。将观测到的羧基和n -十八烷基端链纳米粒子的紫外可见光谱与模型纳米粒子的计算光谱进行比较，可以得知基面上π - π*跃迁对可见光区吸收的贡献。NG的二聚体结构和十八烷基安装的NG表明，扭曲的基面和官能团之间的空间接触扩大了表面到表面的距离，从而允许溶剂分子在表面之间侵入。这一结果与边修饰的纳米颗粒溶解度的提高是一致的。
Computational studies have often been carried out on hydrogen‐terminated nanographenes (NGs). These structures are, however, far from those deduced from experimental observations, which have suggested armchair edges with two carboxy groups on the edges as dominant. We conducted computational studies on NGs consisting of C42, C60, C78, C96, C142, and C174carbon atoms with hydrogen, carboxy, andN‐methyl imide‐terminated armchair edges. DFT calculations inform distorted basal planes and similar HOMO‐LUMO gaps, indicating that the edge oxidation and functionalization do not very influence the electronic structure. Comparison of observed UV‐vis spectra of carboxy‐ andN‐octadecyl chain terminated NGs with calculated spectra of model NGs informs the contribution of π‐π* transitions on the basal plane to the absorptions in the visible region. A dimeric structure of NG and octadecyl‐installed NG demonstrate that both the distorted basal planes and the steric contacts among the functional groups widen the surface‐to‐surface distance thereby allowing the invasion of solvent molecules between the surfaces. This picture is consistent with the improved solubility of edge‐modified NGs.