标题： 吡啶功能化三脚架分子在Au(111)上：氢键与金属配位的相互作用 显示英文标题

标题： Pyridyl-functionalized tripod molecules on Au(111): Interplay between H-bonding and metal coordination

摘要： 吡啶功能化的三嗪（T4PT）在Au(111)表面上的自组装行为通过低温扫描隧道显微镜（STM）在超高真空条件下结合密度泛函理论（DFT）计算进行了研究。特别地，我们研究了温度对组装体内分子间相互作用的影响。STM测量结果显示，T4PT分子形成一个有序且紧密排列的结构，在室温沉积后覆盖度为$\leq1$单层时，分子采用平行于Au表面的平面构型。稳定自组装排列的分子间相互作用基于氢键和弱范德华力的组合。在沉积后退火过程中，组装体通过吡啶配体与天然Au原子之间的金属-配体键进一步稳定。在高于$200^{\circ}$°C的温度下进行进一步的沉积后退火导致N-Au键断裂，分子组装体转变为第二种紧密排列的氢键结构。当温度超过$230^{\circ}$°C时，形成了少量共价连接的二聚体，这很可能是由于CH键活化所致。我们通过使用DFT揭示了键合模式的相互作用强度，解释了动力学驱动的结构形成，并将分子构型与结构相似的吡啶功能化的苯（T4PB）进行了比较。 显示英文摘要

摘要： The self-assembly of pyridyl-functionalized triazine (T4PT) was studied on Au(111) using low-temperature scanning tunneling microscopy (STM) under ultra-high vacuum conditions combined with density functional theory (DFT) calculations. In particular, we investigated the effect of temperature on the intermolecular interactions within the assemblies. STM measurements revealed that T4PT molecules form a well-ordered, close-packed structure, with the molecules adopting a planar conformation parallel to the Au surface for coverages $\leq1$ monolayer upon room temperature deposition. The intermolecular interactions stabilizing the self-assembled arrangement is based on a combination of hydrogen bonding and weak van der Waals forces. Upon post-deposition annealing, the assemblies are additionally stabilized by metal-ligand bonding between the pyridyl ligands and native Au adatoms. Further post-deposition annealing at temperatures above $200^{\circ}$C led to the breaking of the N-Au bonds with the molecular assemblies transforming into a second close-packed hydrogen bonded structure. For temperatures exceeding $230^{\circ}$C, few covalently linked dimers formed, most likely as a result of CH-bond activation. We rationalize the kinetically-driven structure formation by unveiling the interaction strengths of the bonding motifs using DFT and compare the molecular conformation to the structurally similar pyridyl-functionalized benzene (T4PB).