Electro-mechanically switchable hydrocarbons based on [8]annulenes

Magdalena Tasić; Jakov Ivković; Göran Carlström; Michaela Melcher; Paolo Bollella; Jesper Bendix; Lo Gorton; Petter Persson; Jens Uhlig; Daniel Strand

doi:10.1038/s41467-022-28384-8

Electro-mechanically switchable hydrocarbons based on [8]annulenes

Nat Commun. 2022 Feb 14;13(1):860. doi: 10.1038/s41467-022-28384-8.

Authors

Affiliations

¹ Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
² Department of Analytical Chemistry/Biochemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
³ Department of Chemistry, University of Bari "A. Moro", Via E. Orabona 4, 70125, Bari, Italy.
⁴ Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen, Denmark.
⁵ Division of Theoretical Chemistry, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
⁶ Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
⁷ Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden. Daniel.Strand@chem.lu.se.

Abstract

Pure hydrocarbons with shape and conjugation properties that can be switched by external stimuli is an intriguing prospect in the design of new responsive materials and single-molecule electronics. Here, we develop an oligomeric [8]annulene-based material that combines a remarkably efficient topological switching upon redox changes with structural simplicity, stability, and straightforward synthesis: 5,12-alkyne linked dibenzo[a,e]cyclooctatetraenes (dbCOTs). Upon reduction, the structures accommodate a reversible reorganization from a pseudo-conjugated tub-shape to a conjugated aromatic system. This switching in oligomeric structures gives rise to multiple defined states that are deconvoluted by electrochemical, NMR, and optical methods. The combination of stable electromechanical responsivity and ability to relay electrons stepwise through an extended (pseudo-conjugated) π-system in partially reduced structures validate alkyne linked dbCOTs as a practical platform for developing new responsive materials and switches based on [8]annulene cores.