Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, PR China.
Langmuir. 2010 Jul 6;26(13):10791-5. doi: 10.1021/la1006007.
Intermolecular interactions involving aromatic rings are of pivotal importance in many areas of chemistry, biology and materials science. Mimicking recent atomic force microscopy (AFM) experiments that measured the adhesion forces of single pi-pi complexes, here interactions between pyrene/coronene and graphite have been probed by force-probe molecular dynamics (FPMD) simulations. The pyrene or coronene molecule was connected to a virtual spring through a flexible poly(ethylene glycol) (PEG) linker and was pulled away from graphite in water under constant velocity. Pyrene and coronene showed similar unbinding pathways featuring four states, with a transition and an intermediate state connecting the bound and unbound states in terms of distance and interplanar angles. Transient conformations with tilted orientations (approximately 40 degrees) and with one side of the aromatic structure still in contact with the graphite surface (approximately 70 degrees) were identified as the transition and intermediate states, respectively, similar to previously observed perpendicularly stacked benzene dimers. The distance to transition state x(tr) was determined to be 0.23 +/- 0.03 nm both for pyrene/graphite and coronene/graphite. The complexes share similar unbinding pathways, but coronene binds to graphite more strongly than to pyrene.
分子间涉及芳环的相互作用在化学、生物学和材料科学的许多领域都至关重要。本研究模拟了最近原子力显微镜（AFM）测量单π-π配合物粘附力的实验，通过力探针分子动力学（FPMD）模拟研究了芘/蒄和石墨之间的相互作用。芘或蒄分子通过柔性聚乙二醇（PEG）连接体与虚拟弹簧相连，并在恒定速度下从水中的石墨表面拉开。芘和蒄呈现出相似的解缚途径，具有四个状态，其中一个过渡态和一个中间态在距离和层间角度上连接了束缚态和非束缚态。识别出具有倾斜取向（约 40 度）和芳香结构的一侧仍与石墨表面接触（约 70 度）的瞬态构象分别为过渡态和中间态，类似于先前观察到的垂直堆叠的苯二聚体。确定芘/石墨和蒄/石墨的过渡态 x(tr)距离均为 0.23 ± 0.03nm。这些配合物具有相似的解缚途径，但蒄与石墨的结合比与芘的结合更强。
