Self-assembly of N-heterocyclic carbenes on Au(111).
Self-assembly of N-heterocyclic carbenes on Au(111).
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DOI：
10.1038/s41467-021-23940-0
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发表时间：
2021-06-29
影响因子：
16.6
通讯作者：
McLean AB
中科院分区：
文献类型：
--
作者：
Inayeh A;Groome RRK;Singh I;Veinot AJ;de Lima FC;Miwa RH;Crudden CM;McLean AB
虽然几十年来有机配体在金表面的自组装一直被硫基配体所主导，但一种新的配体--N-杂环卡宾（NHCs）的出现却成为了一种有趣的替代物，然而围绕这一新配体的自组装的基本问题仍然没有得到解答。在这里，我们描述了NHC结构，表面覆盖，和衬底温度对迁移率，热稳定性，NHC表面几何形状，和自组装的影响。通过扫描隧道显微镜和密度泛函理论对NHC吸附和自组装的分析揭示了NHC-表面相互作用和NHC-NHC相互作用对NHC单层结构的重要性。一个显着的方式，这些相互作用的表现是需要一个阈值NHC表面覆盖率，以产生直立，adatom介导的吸附图案与低表面扩散。NHC的翼尖结构也很关键，主要取代基导致形成平坦的NHC 2Au复合物，当分离时具有高流动性，但在较高的表面浓度下自组装成稳定有序的晶格。这些和其他NHC表面化学研究将对这些下一代单分子膜的成功至关重要。虽然N-杂环卡宾（NHC）是一类很有前途的配体，用于在金属表面形成坚固的自组装单分子膜，但关于其在表面上的行为仍存在许多问题。在这里，作者解决这些基本问题，如控制NHC的方向，流动性和自组装能力的因素-通过深入研究Au（111）上的NHC覆盖层。
Although the self-assembly of organic ligands on gold has been dominated by sulfur-based ligands for decades, a new ligand class, N-heterocyclic carbenes (NHCs), has appeared as an interesting alternative. However, fundamental questions surrounding self-assembly of this new ligand remain unanswered. Herein, we describe the effect of NHC structure, surface coverage, and substrate temperature on mobility, thermal stability, NHC surface geometry, and self-assembly. Analysis of NHC adsorption and self-assembly by scanning tunneling microscopy and density functional theory have revealed the importance of NHC-surface interactions and attractive NHC-NHC interactions on NHC monolayer structures. A remarkable way these interactions manifest is the need for a threshold NHC surface coverage to produce upright, adatom-mediated adsorption motifs with low surface diffusion. NHC wingtip structure is also critical, with primary substituents leading to the formation of flat-lying NHC2Au complexes, which have high mobility when isolated, but self-assemble into stable ordered lattices at higher surface concentrations. These and other studies of NHC surface chemistry will be crucial for the success of these next-generation monolayers. Although N-heterocyclic carbenes (NHCs) are a promising class of ligands for forming robust self-assembled monolayers on metals, many questions remain about their behavior on surfaces. Here, the authors address these fundamental questions—such as the factors controlling NHC orientation, mobility, and ability to self-assemble—through an in-depth examination of NHC overlayers on Au(111).
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影响因子：
15
作者：
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通讯作者：
Woolfson DN
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通讯作者：
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通讯作者：
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影响因子：
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