Solution-Mediated Annealing Pathways Are Critical for Supramolecular Ordering of Complex Macrocycles at Surfaces
Solution-Mediated Annealing Pathways Are Critical for Supramolecular Ordering of Complex Macrocycles at Surfaces
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DOI：
10.1021/acs.jpcc.9b11867
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发表时间：
2020-03-26
影响因子：
3.7
通讯作者：
Tait, Steven L.
中科院分区：
文献类型：
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作者：
Castillo, Henry D.;Yang, Jing;Tait, Steven L.
超分子组装体在表面的自组织通常实现高度有序的二维堆积结构，这是由于各种分子间相互作用协商成最小自由能构型。然而，当我们朝着实现可编程表面功能的长期目标推进这些系统时，我们考虑在分子构建块架构和生长条件中具有更大复杂性的系统。在这里，我们研究的多晶型自组装的tricarbazolo triazolophane大环化合物（tricarb）在溶液/固体界面，以确定潜在的途径，tricarb遵循两种结构之间的转换。三碳物种，取决于周边功能化，自组装成动力学捕获的无序结构或philically有利的有序蜂窝结构。不同的实验前和后沉积条件（溶解度，浓度和温度）表明，溶液介导的退火途径，而不是表面重排，是从无序结构过渡到蜂窝状的关键。分子动力学模拟提供了纳米尺度的洞察力的作用，外围基团和溶剂分子在自组装。分子外部的取代基不仅影响溶解度，而且还稳定三碳-三碳氢键结构。外围基团影响吸附物-吸附物接触的形成/再形成和强度，并且还限制大环核周围的溶剂相互作用。模拟和实验的结合证明了溶液介导的退火途径在复杂超分子体系自组装中的作用。
Self-organizations of supramolecular assemblies at surfaces typically achieve highly ordered two-dimensional packing structures due to the negotiation of various intermolecular interactions into a minimum free energy configuration. As we advance these systems toward the long-term goal of achieving programmable surface functionality, however, we consider systems of greater complexity in molecular building-block architecture and in growth conditions. Here, we study the polymorphic self-assembly of tricarbazolo triazolophane macrocycles (tricarb) at the solution/solid interface to determine the underlying pathway that tricarb follows when it transitions between two structures. Tricarb species, depending on peripheral functionalization, self-assemble into kinetically trapped disordered structures or thermodynamically favored ordered honeycomb structures. Experiments varying pre- and post-deposition conditions (solubility, concentration, and temperature) suggest that a solution-mediated annealing pathway, as opposed to an on-surface rearrangement, is key to a transition from disordered structures to honeycomb. Molecular dynamic simulations provide nanoscale insights into the roles of peripheral groups and solvent molecules in self-assembly. Substituents on the exterior of the molecule not only affect solubility but also stabilize tricarb-tricarb hydrogen-bonded structures. Peripheral groups influence the formation/re-formation and strength of adsorbate-adsorbate contacts and also limit solvent interactions about a macrocyclic core. The combination of simulation and experiment demonstrates the role of the solution-mediated annealing pathway in the self-assembly of complex supramolecular systems.