Toward an Understanding of Diamond sp(2)-Defects with Unsaturated Diamondoid Oligomer Models.
Toward an Understanding of Diamond sp(2)-Defects with Unsaturated Diamondoid Oligomer Models.
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DOI：
10.1021/jacs.5b01555
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发表时间：
2015-05
影响因子：
15
通讯作者：
T. Zhuk;Tatyana V. Koso;A. Pashenko;N. Hoc;V. N. Rodionov;M. Serafin;P. Schreiner;A. Fokin
中科院分区：
文献类型：
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作者：
T. Zhuk;Tatyana V. Koso;A. Pashenko;N. Hoc;V. N. Rodionov;M. Serafin;P. Schreiner;A. Fokin
以酮为原料，通过McMurry偶联法合成了具有sp（2）缺陷的纳米级双键类金刚石二聚体和三聚体，并对其进行了光谱和晶体学表征。利用密度泛函理论（DFT）和从头算（MP2）方法研究了中性烃及其自由基阳离子，再现实验几何构型和电离势。低聚物与它们的自由基阳离子的货车德瓦耳斯络合物是类金刚烷自组装的模型，形成高度离域和对称的缺电子结构。这意味着烃类中的σ-离域程度相当高，与离域π-体系没有太大不同。因此，sp（2）缺陷也被认为是非局域的，从而导致观察到的类金刚石材料的高表面电荷迁移率。为了能够使用的金刚烷低聚物用于随后的表面附着和改性，其C-H-键的官能化进行了研究，这些提供了卤素和羟基衍生物与不饱和度的保护。
Nanometer-sized doubly bonded diamondoid dimers and trimers, which may be viewed as models of diamond with surface sp(2)-defects, were prepared from corresponding ketones via a McMurry coupling and were characterized by spectroscopic and crystallographic methods. The neutral hydrocarbons and their radical cations were studied utilizing density functional theory (DFT) and ab initio (MP2) methods, which reproduce the experimental geometries and ionization potentials well. The van der Waals complexes of the oligomers with their radical cations that are models for the self-assembly of diamondoids, form highly delocalized and symmetric electron-deficient structures. This implies a rather high degree of σ-delocalization within the hydrocarbons, not too dissimilar to delocalized π-systems. As a consequence, sp(2)-defects are thus also expected to be nonlocal, thereby leading to the observed high surface charge mobilities of diamond-like materials. In order to be able to use the diamondoid oligomers for subsequent surface attachment and modification, their C-H-bond functionalizations were studied, and these provided halogen and hydroxy derivatives with conservation of unsaturation.