Self-Metalation of 2H-Tetraphenylporphyrin on Cu(111) Studied with XSW: Influence of the Central Metal Atom on the Adsorption Distance
Self-Metalation of 2H-Tetraphenylporphyrin on Cu(111) Studied with XSW: Influence of the Central Metal Atom on the Adsorption Distance
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DOI：
10.1021/jp503046w
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发表时间：
2014-06-26
影响因子：
3.7
通讯作者：
Schreiber, F.
中科院分区：
文献类型：
--
作者：
Buerker, C.;Franco-Canellas, A.;Schreiber, F.
利用X射线驻波（XSW）研究了π共轭有机化合物2 H-四苯基卟啉（2 HTPP）和铜（II）-四苯基卟啉（CuTPP）在Cu（111）表面的室温和低温吸附.利用2 HTPP热活化自金属化成CuTPP的特点，研究了中心金属原子对分子与衬底表面键合距离的影响。2 HTPP的碳原子和氮原子的平均吸附距离之间的比较揭示了一个扭曲的分子与氮原子更接近表面比碳的平均。此外，测量的位置的两个化学不等价类型的氮原子（亚胺和氨基）的2 HTPP表明扭曲的卟啉环。在500 K下从2 HTPP到CuTPP的化学反应之后，没有看到碳骨架的吸附距离的变化，但是整个分子变得平坦。尽管金属化后的变化，两种分子的吸附距离显示出较强的相互作用与基板相比，类似的π共轭分子。
We present a systematic X-ray standing wave (XSW) study of the pi-conjugated organic compound 2H-tetraphenylporphyrin (2HTPP) and copper(II)-tetraphenylporphyrin (CuTPP) on Cu(111) at room and low temperatures. We exploit the feature of thermally activated self-metalation of 2HTPP to CuTPP to study the influence of the central metal atom on the bonding distance of the molecule to the substrate surface. Comparison between the average adsorption distances of the carbon and nitrogen atoms of 2HTPP reveals a distorted molecule with the nitrogen atoms being closer to the surface than the carbon ones on average. Additionally, the measured positions of the two chemically inequivalent types of nitrogen atoms (iminic and aminic) of 2HTPP indicate a distorted porphyrin ring. After the chemical reaction from 2HTPP to CuTPP at 500 K, no change of the adsorption distance of the carbon skeleton is seen, but the entire molecule becomes flattened. Despite the changes upon metalation, adsorption distances for both molecules show a strong interaction with the substrate in comparison to similar pi-conjugated molecules.