NCAFM2023 Programme Booklet

Friday 0900 - 0920

H. Mönig 1 , J. Ren 1 , M. Koy 2 , H. Osthues 3 , B. Schulze Lammers 1 , C. Gutheil 2 , M. Nyenhuis 3 , Q. Zheng 4 , Y. Xiao 4 , Li Huang 4 , Q. Dai 5 , H.-J. Gao 4 , N.L. Doltsinis 3 , H. Fuchs 1 , F. Glorius 2 1 Physikalisches Institut, University of Münster, 48149 Münster 2 Organisch-Chemisches Institut, University of Münster, 48149 Münster 3 Institute for Solid State Theory, University of Münster, 48149 Münster 4 Beijing National Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190 5 CAS Key Laboratory of Nanophotonic Materials and Devices National Center for Nanoscience and Technology, Beijing 100190 Email: harry.moenig@uni-muenster.de ON SURFACE SYNTHESIS OF BALLBOT TYPE N HETEROCYCLIC CARBENE POLYMERS Surface modification by N-heterocyclic carbenes (NHCs) is a powerful approach in various fields in organic chemistry [1]. To increase their stability on flat surfaces and nano-particles, a covalent coupling between neighboring monomeric units is highly desirable. Here we succeeded in the polymerization of NHCs using Ullman coupling on gold substrates [2]. The high mobility of the precursors prior to polymerization and height measurements based on force spectroscopy indicate that the polymer units are bound to single Au adatoms (ballbot-type configuration). The conformational details revealed by a detailed analysis of the sub-molecular force contrast recorded with an O-terminated copper tip (CuOx-tip) [3] in conjunction with corresponding AFM simulations and first principles calculations, strongly confirm the ballbot-type nature. The resulting high mobility of the incommensurate NHC polymers is a key prerequisite for gaining a high degree of directionality, which is demonstrated on a Au(100) surface. Our results set the ground for the development of carbene-based supramolecular structures and nanomaterials for applications in surface functionalization and catalysis.

Fig. a,b NC-AFM images of NHC ballbot-polymers on a Au(111) surface recorded with a CuOx-tip. c , Corresponding DFT-optimized model. d , Comparative height analysis by force spectroscopy (CO-tip) for ballbot-, and non-ballbot species. e, Corresponding DFT models.. References [1] P. Bellotti, M. Koy, M.N. Hopkinson, F. Glorius, Nat. Rev. Chem., 2021, 5 , 711. [2] J. Ren, M. Koy, H. Osthues, B. Schulze Lammers, C. Gutheil, M. Nyenhuis, Q. Zheng, Y. Xiao,Li Huang, A. Nalop, Q. Dai, H.-J. Gao, H. Mönig, N.L. Doltsinis, H. Fuchs, F. Glorius, to be published 2023. [2] H. Mönig, S. Amirjalayer, A. Timmer, Z. Hu, L. Liu, O. Díaz Arado, M. Cnudde, C.A. Strassert, W. Ji, M. Rohlfing, H. Fuchs, Nat. Nanotechnol., 2018, 13 , 371.

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