Discovery of an Interlocked and Interwoven Molecular Topology in Nanocarbons via Dynamic C–C Bond Formation

Creators: Bergman, Harrison M.¹; Fan, Angela T.¹; Jones, Christopher G.^{2, 3}; Rothenberger, August J.¹; Jha, Kunal K.³; Handford, Rex C.¹; Nelson, Hosea M.³; Liu, Yi⁴; Tilley, T. Don¹

1. University of California, Berkeley
2. University of California, Los Angeles
3. California Institute of Technology
4. Lawrence Berkeley National Laboratory

Abstract

Topologically complex carbon nanostructures are an exciting but largely unexplored class of materials due to their challenging synthesis. Previous methods are low yielding because they rely on irreversible C_sp²-C_sp² bond formation, which necessitates complex templating strategies to enforce entanglement. Here, reversible zirconocene coupling of alkynes is developed as a new method to access complex molecular topologies, where dynamic C-C bond formation facilitates entanglement under thermodynamic control, allowing the use of simple precursors without the need for preassembly. This strategy enables the scalable, high-yield synthesis of three topologically distinct nanocarbons, including the serendipitous discovery of a structure containing a new topological motif that was not previously identified or realized synthetically. This motif, consisting of an unusual combination of interlocking and interweaving, was recognized to be generalizable to a new topological class of molecules, introduced here as perplexanes.

Copyright and License

This publication is licensed under CC-BY 4.0 .

Acknowledgement

This work was funded by the National Science Foundation under Grant No. CHE-2103696. Work performed at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, US Department of Energy under contract no. DE-AC02-05CH11231. This work includes research that was performed at beamline 24-ID-C of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357, and at beamline 12.2.1 of the Advanced Light Source, a U.S. DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. We thank Dr. Hasan Celik and UC Berkeley’s NMR facility in the College of Chemistry (CoC-NMR) for spectroscopic assistance. Instruments in the CoC-NMR are supported in part by NIH S10OD024998. We thank Dr. Simon Teat (ALS, LBNL) for providing a preliminary crystallographic solution of 3-Zr (via The Advanced Light Source, which is supported by the Director, Office of Science, Office of Basic Energy Sciences, U.S. Department of Energy under contract no. DE-AC02-05CH11231) that enabled early confirmation of its structure. We thank Dr. Zoe Ashbridge for helpful discussions about topological nomenclature concerning compound 3. We thank Rob Scharien for guidance and technical support in using his KnotPlot software to visualize the perplexanes in Figure 4.

Funding

National Science Foundation grant CHE-2103696 (TDT); Office of Science, Office of Basic Energy Sciences, US Department of Energy grant DE-AC02–05CH11231 (YL).

Supplemental Material

General materials and methods, synthetic procedures, reaction optimization data, 1D and 2D nuclear magnetic resonance (NMR) characterization, matrix assisted laser desorption ionization (MALDI) mass spectrometry data, absorption and emission spectra, X-ray crystallography data and analysis, and detailed topological discussion (PDF)

Additional Information

Accession Codes. CCDC 2313007, and 2313008, and 2313018 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

Files

bergman-et-al-2025-discovery-of-an-interlocked-and-interwoven-molecular-topology-in-nanocarbons-via-dynamic-c-c-bond.pdf

Name	Size	Download all
bergman-et-al-2025-discovery-of-an-interlocked-and-interwoven-molecular-topology-in-nanocarbons-via-dynamic-c-c-bond.pdf md5:d1c8568f3698257c3201307c8f1d45cf	3.6 MB	Preview Download
ja5c04268_si_001.pdf md5:6ea1a5956ceb9159bd506102ed4bd7c6	2.0 MB	Preview Download

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes