We investigate the impact of peripheral cyano functionalization of the previously well-studied 2H-tetraphenylporphyrin (2HTPP) by scanning tunneling microscopy (STM) and density functional theory (DFT). The adsorption behavior of 2H-tetrakis(p-cyano)-phenylporphyrin (2HTCNPP) is studied at room temperature and at 80 K on Cu(111) and Ag(111). Interestingly, the cyano-functionalized porphyrins tend to form isolated 1D chains on Cu(111), in particular after mild annealing at 350 K. The individual 2HTCNPPs as well as the formed chains are oriented along the main crystallographic directions of the Cu(111) substrate due to a strongly attractive and site-specific interaction between the iminic nitrogens of the 2HTCNPP and Cu substrate atoms. The linking within the 1D molecular chains is realized by Cu adatoms as evidenced by comparison of STM and DFT. In contrast, on Ag(111) the molecules assemble into 2D supramolecular layers with long-range order and a square unit cell, stabilized by molecule–molecule interactions. The orientation of the molecules with respect to the unit cell lattice vectors leads to organizational chirality. By codeposition of cobalt, the porphyrin molecules are metalated at room temperature. We did not observe any evidence for metal–organic network formation on Ag(111), even after varying the deposition parameters or the order of metal and porphyrin deposition. Our study shows that cyano functionalization of porphyrins can give rise to novel and unique self-assembled structures like 1D molecular chains without any cross-connections via adatom linking.

中文翻译：

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氰基功能化卟啉在Cu（111）和Ag（111）上的吸附行为：从分子线到有序的超分子二维聚集体。

我们通过扫描隧道显微镜（STM）和密度泛函理论（DFT）研究了先前研究充分的2 H-四苯基卟啉（2HTPP）的外围氰基官能化的影响。2 H-四（p）的吸附行为-氰基）-苯基卟啉（2HTCNPP）在室温和80 K的Cu（111）和Ag（111）上进行了研究。有趣的是，氰基官能化的卟啉倾向于在Cu（111）上形成分离的1D链，特别是在350 K轻度退火后。各个2HTCNPPs以及形成的链都沿着Cu（111）的主要晶体学方向取向由于2HTCNPP的亚氨基氮与Cu底物原子之间存在强烈的吸引力和位点特异性相互作用，因此该底物具有很高的吸引力。一维分子链内的连接是通过Cu原子实现的，如STM和DFT的比较所证明。相比之下，在Ag（111）上，分子组装成具有远距离有序的二维超分子层和一个方形晶胞，并通过分子-分子相互作用而稳定。分子相对于晶胞晶格矢量的取向导致组织手性。通过钴的共沉积，卟啉分子在室温下被金属化。即使改变沉积参数或金属和卟啉沉积的顺序，我们也没有观察到在Ag（111）上形成金属有机网络的任何证据。我们的研究表明，卟啉的氰基官能化可以产生新颖且独特的自组装结构，例如一维分子链，而不会通过原子连接而产生任何交叉连接。即使在改变沉积参数或金属和卟啉沉积顺序之后也是如此。我们的研究表明，卟啉的氰基官能化可以产生新颖且独特的自组装结构，例如一维分子链，而不会通过原子连接而产生任何交叉连接。即使在改变沉积参数或金属和卟啉沉积顺序之后也是如此。我们的研究表明，卟啉的氰基官能化可以产生新颖且独特的自组装结构，例如一维分子链，而不会通过原子连接而产生任何交叉连接。