Institute for Computational Physics , Universität Stuttgart , Allmandring 3 , 70569 Stuttgart , Germany.
Institute of Physics , Chinese Academy of Sciences , Zhongguancun , Beijing 100190 , China.
J Phys Chem A. 2018 Apr 12;122(14):3583-3593. doi: 10.1021/acs.jpca.7b12519. Epub 2018 Mar 30.
The rational control of the electronic and optical properties of small functionalized diamond-like molecules, the diamondoids, is the focus of this work. Specifically, we investigate the single- and double- functionalization of the lower diamondoids, adamantane, diamantane, and triamantane with -NH and -SH groups and extend the study to N-heterocyclic carbene (NHC) functionalization. On the basis of electronic structure calculations, we predict a significant change in the optical properties of these functionalized diamondoids. Our computations reveal that -NH functionalized diamondoids show UV photoluminescence similar to ideal diamondoids while -SH substituted diamondoids hinder the UV photoluminescence due to the labile nature of the S-H bond in the first excited state. This study also unveils that the UV photoluminescence nature of -NH diamondoids is quenched upon additional functionalization with the -SH group. The double-functionalized derivative can, thus, serve as a sensitive probe for biomolecule binding and sensing environmental changes. The preserved intrinsic properties of the NHC and the ideal diamondoid in NHC-functionalized-diamondoids suggests its utilization in diamondoid-based self-assembled monolayers (SAM), whose UV-photoluminescent signal would be determined entirely by the functionalized diamondoids. Our study aims to pave the path for tuning the properties of diamondoids through a selective choice of the type and number of functional groups. This will aid the realization of optoelectronic devices involving, for example, large-area SAM layers or diamondoid-functionalized electrodes.
这项工作的重点是对小分子功能化类似金刚石的分子（类金刚石）的电子和光学性质进行合理控制。具体而言，我们研究了 -NH 和 -SH 基团对较低的类金刚石（金刚烷、双环戊二烯和三亚甲基）的单官能化和双官能化，并将研究扩展到氮杂环卡宾（NHC）官能化。基于电子结构计算，我们预测这些官能化类金刚石的光学性质会发生显著变化。我们的计算表明，-NH 官能化的类金刚石显示出类似于理想类金刚石的紫外光致发光，而 -SH 取代的类金刚石由于第一激发态中 S-H 键的不稳定性而阻碍了紫外光致发光。这项研究还揭示了 -NH 类金刚石的紫外光致发光性质在与 -SH 基团进一步官能化后被猝灭。因此，双官能化衍生物可以作为生物分子结合和感测环境变化的敏感探针。NHC 双官能化衍生物保留了 NHC 的固有性质和理想类金刚石的性质，表明其可用于基于类金刚石的自组装单层（SAM），其紫外光致发光信号将完全由官能化的类金刚石决定。我们的研究旨在通过选择合适的官能团类型和数量来调节类金刚石的性质，为其铺平道路。这将有助于实现涉及大面积 SAM 层或类金刚石功能化电极的光电设备。
