New Carbon Allotropes and Nanographenes: Prototyping via On-Surface Synthesis and Single-Molecule Manipulation

by Prof. Dr. Michael Gottfried

Tuesday Oct 28, 2025, 4:15 PM → 6:00 PM Europe/Berlin

H6 (UHG)

Recent advancements of on-surface synthesis techniques enable the fabrication and precise characterization of carbon-based nanomaterials with atomic-scale precision. These materials often exhibit novel (opto)electronic and magnetic properties, arising both from the intrinsic features of the molecular precursors and the unique structures formed during synthesis. On-surface synthesis thus provides a highly versatile alternative to conventional solution-phase chemistry, giving access to
products that are otherwise synthetically inaccessible.
In particular, the search for nonbenzenoid  sp^2 carbon allotropes has driven substantial research due to their predicted unique mechanical, electronic, and transport properties. However, their synthesis remains challenging owing to the lack of reliable protocols for generating nonhexagonal rings. We have developed various on-surface synthesis strategies by which polymer chains are linked to form nonbenzenoid carbon networks. This approach enabled the synthesis of biphenylene network, a carbon allotrope with 4-, 6-, and 8-membered rings (Figure 1a), which exhibits metallic behaviour already at very small dimensions [1], along with other novel carbon networks.
Acenes represent another key class of carbon materials with potential for use in organic electronics. Using multistep single-molecule manipulation, we synthesized tridecacene (13ac) [2] and pentadecacene (15ac) [3], the longest acenes known to date (Figure 1b). We find antiferromagnetic open-shell ground state electron configurations for both acenes. Notably, 15ac shows a low-bias spin-excitation feature, indicating a singlet-triplet gap of around 124 meV. Investigation of 15ac complexes with up to 6 gold atoms suggest considerable multiradical contributions to the electronic ground state of 15ac.
Doping with heteroatoms alters the electronic and magnetic properties of carbon-based nanomaterials. We present a variety of nitrogen-containing carbon nanostructures including planar and curved cycloarenes (Figure 1c) as well as N-doped graphene nanoribbons and acenes [4].

References:
[1] Q.T. Fan et al., J.M. Gottfried, Science 372, 852-856 (2021), 10.1126/science.abg4509.
[2] Z. Ruan et al., J.M. Gottfried, J. Am. Chem. Soc. 146, 3700-3709 (2024), 10.1021/jacs.3c09392.
[3] Z. Ruan et al., J.M. Gottfried, J. Am. Chem. Soc. 147, 4862–4870 (2025), 10.1021/jacs.4c13296.
[4] Z. Ruan et al., J.M. Gottfried, Angew. Chem. Int. Ed. e202504707 (2025), 10.1002/anie.202504707.

 

Figure 1. (a) Biphenylene network, (b) long acenes by single-molecule manipulation, (c) N-doped cycloarene.

 

 

 

J. Michael Gottfried is a professor (W3) of Physical Chemistry at the University of Marburg, Germany. His current research interests encompass on-surface synthesis, cyclic nanographenes, synthetic carbon allotropes, non-benzenoid aromatic systems, and porphyrin-based materials, which are generated and studied using advanced surface-science techniques. He received his PhD degree in 2003 from the Freie Universität Berlin, after studies of Chemistry and Physics in Darmstadt, St. Andrews, and Berlin. After postdoctoral research at the University of Washington (with C.T. Campbell), and habilitation at the Universität Erlangen-Nürnberg (with H.-P. Steinrück), he was appointed to a professorship at the University of Marburg in 2011. The held a guest professorship at the University of Science and Technology of China (USTC) and received the International Partnership Award for Young Scientists of the Chinese Academy of Sciences and the SCS Lectureship of the Swiss Chemical Society, among other awards. He has been the vice-spokesperson of the Research Center CRC 1083 “Structure and Dynamics of Internal Interfaces” of the German Science Foundation since 2021 and received an ERC Synergy Grant in 2022. Publications: https://scholar.google.com/citations?hl=en&user=NtrpwsEAAAAJ

 

 

2025-10-28_Prof.MichaelGottfried.pdf