Single-molecule level control of host-guest interactions in metallocycle-C60 complexes

• Published in: Nature communications 2019-10, Vol.10 (1), p.1-9, Article 4599
• Main Authors: Tang, Jian-Hong, Li, Yueqi, Wu, Qingqing, Wang, Zixiao, Hou, Songjun, Tang, Kun, Sun, Yue, Wang, Hui, Wang, Heng, Lu, Cheng, Wang, Xiang, Li, Xiaopeng, Wang, Dong, Yao, Jiannian, Lambert, Colin J., Tao, Nongjian, Zhong, Yu-Wu, Stang, Peter J.
• Format: Article
• Language: English
• Subjects: 119/118; 639/638/541; 639/638/911; Biological activity; Buckminsterfullerene; Charge transport; Chemical reactions; Chemistry; Conductance; Fullerenes; Humanities and Social Sciences; Laboratories; Microscopy; multidisciplinary; Organic chemistry; Resistance; Scanning tunneling microscopy; Science; Science (multidisciplinary); Stretching; Supramolecular compounds; Switches; Transport properties
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-12534-6

Host−guest interactions are of central importance in many biological and chemical processes. However, the investigation of the formation and decomplexation of host−guest systems at the single-molecule level has been a challenging task. Here we show that the single-molecule conductance of organoplatinum(II) metallocycle hosts can be enhanced by an order of magnitude by the incorporation of a C 60 guest molecule. Mechanically stretching the metallocycle-C 60 junction with a scanning tunneling microscopy break junction technique causes the release of the C 60 guest from the metallocycle, and consequently the conductance switches back to the free-host level. Metallocycle hosts with different shapes and cavity sizes show different degrees of flexibility to accommodate the C 60 guest in response to mechanical stretching. DFT calculations provide further insights into the electronic structures and charge transport properties of the molecular junctions based on metallocycles and the metallocycle-C 60 complexes. Studying the single-molecule behavior of host-guest complexes can provide fundamental insights into their supramolecular interactions. Here, the authors use the scanning tunneling microscopy break junction technique to show that encapsulation of a C 60 molecule significantly enhances the conductance of an organoplatinum metallocycle; mechanical stretching of the junction releases the guest, returning the conductance to free-host level.