Diffusion, Rotation, and Surface Chemical Bond of Individual 2H-Tetraphenylporphyrin Molecules on Cu(111)
Diffusion, Rotation, and Surface Chemical Bond of Individual 2H-Tetraphenylporphyrin Molecules on Cu(111)
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DOI：
10.1021/jp206675u
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发表时间：
2011-12-15
影响因子：
3.7
通讯作者：
Marbach, Hubertus
中科院分区：
文献类型：
--
作者：
Buchner, Florian;Xiao, Jie;Marbach, Hubertus
本文利用变温扫描隧道显微镜（STM）和X射线光电子能谱（XPS）研究了室温下2 H-四苯基卟啉（2 HTPP）在Cu（111）表面的动力学行为和表面化学键。在280和345 K之间，分子主要显示单向扩散沿着的三个密集的衬底方向之一< 110 >，这是由于吸附物-衬底键的高位点选择性。在305 K以上，扩散方向偶尔会改变+/- 120度。单向扩散和扩散方向旋转的激活势垒分别确定为0.71 +/- 0.08和1.28 +/- 0.12 eV。XPS分析表明，2 HTPP的亚胺氮原子与Cu表面有较强的相互作用。据推测，当地的键合情况是类似的初始复杂（坐在顶部复杂），这是以前观察到的表面限制在原位金属化的卟啉。
We address the dynamic behavior and the surface chemical bond of 2H-tetraphenylporphyrin (2HTPP) on Cu(111) around room temperature by variable-temperature scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum. Between 280 and 345 K, the molecules predominantly display unidirectional diffusion along one of the three densely packed substrate < 110 > directions, which is attributed to a high site selectivity of the adsorbate-substrate bond. Above 305 K, the diffusion direction is found to change occasionally by +/- 120 degrees. The activation barriers for the unidirectional diffusion and for rotation of the diffusion direction are determined to 0.71 +/- 0.08 and 1.28 +/- 0.12 eV, respectively. XPS shows that the iminic nitrogen atoms of 2HTPP interact strongly with the Cu surface. It is postulated that the local bonding situation is similar as in the initial complex (sitting-atop complex), which has previously been observed during the surface-confined in situ metalation of porphyrins.