NCAFM2023 Programme Booklet

Thursday 1100 - 1120

ON SURFACE SYNTHESIS OF MICROMETER LONG POLY PARA PHENYLENE BY RING OPENING POLYMERIZATION AND ITS FUSION INTO BIPHENYLENE RIBBON

Qitang Fan 1,4 , Qigang Zhong 2 , Jan-Niclas Luy 3 , Daniel Ebeling 2 , Ralf Tonner-Zech 3 , André Schirmeisen 2 , J. Michael Gottfried 1,*

1 Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany 2 Institute of Applied Physics (IAP), Justus Liebig University Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany 3 Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, D-04103 Leipzig, Germany 4 Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China Email: michael.gottfried@chemie.uni-marburg.de The seeking for unsubstituted poly(para-phenylene) (PPP) chains with large molecular weight remains intriguing due to, e.g., its enhanced electrical conductivity and thus higher performance of the PPP-containing organic electronics. Recently, surface-assisted Ullmann coupling has been used to synthesize higher-quality PPP compared to the solution-based reactions. However, the step-growth mode of Ullmann reaction still limits the lengths of PPP. Here, we report the synthesis of PPP through ring-opening polymerization of cycloparaphenylene (CPP) precursor on Cu(111). This process is found to be a chain growth mode, resulting in PPP chains up to 0.9 μm. Moreover, owing to the exemption from halogen co-adsorbates, the formed ultra-long PPP surface undergo selective C-H removal at one side forming the up-standing poly(para-benzyne) (PPB). These PPB chains are able to further couple laterally into the unsubstituted 6-atom wide biphenylene ribbon (Fig. 1), which is achieved here for the first time compared to the fluorinated biphenylene ribbon on Au(111) via HF zipping reaction.[1]

Fig. 1 6-atom wide biphenylene nanoribbon formed by ring-opening polymerization of 6-cycloparaphenylene on Cu(111) surface.

References [1] Fan, Q.; Yan, L.; Tripp, M. W.; Krejčí, O.; Dimosthenous, S.; Kachel, S. R.; Chen, M.; Foster, A. S.; Koert, U.; Liljeroth, P.; Gottfried, J. M. Science 2021, 372: 852.

74