Teunissen Jos L, De Proft Frank, De Vleeschouwer Freija
Research Group of General Chemistry, Vrije Universiteit Brussel (VUB) , Pleinlaan 2, 1050 Brussels, Belgium.
J Chem Theory Comput. 2017 Mar 14;13(3):1351-1365. doi: 10.1021/acs.jctc.6b01074. Epub 2017 Feb 28.
Functionalized diamondoids show great potential as building blocks for various new optoelectronic applications. However, until now, only simple mono and double substitutions were investigated. In this work, we considered up to 10 and 6 sites for functionalization of the two smallest diamondoids, adamantane and diamantane, respectively, in search for diamondoid derivatives with a minimal and maximal HOMO-LUMO energy gap. To this end, the energy gap was optimized systematically using an inverse molecular design methodology based on the best-first search algorithm combined with a Monte Carlo component to escape local optima. Adamantane derivatives were found with HOMO-LUMO gaps ranging from 2.42 to 10.63 eV, with 9.45 eV being the energy gap of pure adamantane. For diamantane, similar values were obtained. The structures with the lowest HOMO-LUMO gaps showed apparent push-pull character. The push character is mainly formed by sulfur or nitrogen dopants and thiol groups, whereas the pull character is predominantly determined by the presence of electron-withdrawing nitro or carbonyl groups assisted by amino and hydroxyl groups via the formation of intramolecular hydrogen bonds. In contrast, maximal HOMO-LUMO gaps were obtained by introducing numerous electronegative groups.
功能化金刚烷类化合物作为各种新型光电子应用的构建块具有巨大潜力。然而，到目前为止，仅研究了简单的单取代和双取代。在这项工作中，我们分别考虑了最小的两种金刚烷类化合物金刚烷和双金刚烷最多10个和6个功能化位点，以寻找具有最小和最大HOMO-LUMO能隙的金刚烷类衍生物。为此，使用基于最佳优先搜索算法并结合蒙特卡罗组件以避免局部最优的逆分子设计方法系统地优化能隙。发现金刚烷衍生物的HOMO-LUMO能隙范围为2.42至10.63 eV，纯金刚烷的能隙为9.45 eV。对于双金刚烷，获得了类似的值。具有最低HOMO-LUMO能隙的结构表现出明显的推-拉特性。推电子特性主要由硫或氮掺杂剂以及硫醇基团形成，而拉电子特性主要由吸电子的硝基或羰基的存在决定，氨基和羟基通过形成分子内氢键起到辅助作用。相比之下，通过引入大量电负性基团获得了最大的HOMO-LUMO能隙。
