Advances in chiral carbon-rich molecules incorporating five-membered carbocycles since 2019: Fullerenes, nanographenes, and non-fully conjugated PAHs
*Correspondence to:
Han-Yuan Gong, College of Chemistry, Beijing Normal University, Beijing 100875, China.
E-mail: hanyuangong@bnu.edu.cn
Chiral Chem. 2027;3:202631. 10.70401/cc.2026.0042
Received: July 04, 2026Accepted: October 12, 2026Published: October 15, 2026
This manuscript is made available in its unedited form to allow early access to the
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Abstract
Chiral carbon-rich molecules have attracted increasing attention because they integrate extended π-conjugation with stereochemical complexity, thereby giving rise to circularly polarized luminescence, chiral charge/spin transport, molecular recognition and unconventional open-shell electronic structures. Among the structural elements available for their construction, five-membered carbon rings occupy a particularly important position. This review provides an overview of recent progress in chiral carbon-rich molecules incorporating five-membered carbocyclic motifs, including chiral fullerenes, nonbenzenoid and bowl-shaped nanographenes, helically distorted open-shell systems, and chiral PAHs with interrupted π-conjugation. We emphasize the dual and complementary roles of five-membered carbocycles. In fully conjugated frameworks, pentagons introduce curvature, non-benzenoid topology, perturbed aromaticity and unusual spin/electronic distributions, thereby enabling diverse chiral fullerene and nanographene architectures with distinctive optical, magnetic and supramolecular properties. In frameworks with interrupted π-conjugation, five-membered rings incorporated into spiro-, indane-, or cyclophane-type motifs can rigidify three-dimensional architectures, mediate chirality transfer, attenuate through-bond π-conjugation, and enhance through-space electronic coupling, thereby offering effective design strategies for high-performance chiroptical and optoelectronic systems. By comparing these two regimes, we highlight how five-membered carbocycles have emerged since 2019 as versatile design elements for modulating chirality, topology, and function in carbon-rich molecules, and we discuss current synthetic limitations, unresolved mechanistic questions, and potential future opportunities in photonic, spintronic, and molecular electronic applications.
Keywords
Chiral carbon-rich molecules, five-membered carbon rings, chiral fullerenes, chiral nanographenes, chirality in PAHs
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Wu ZH, Wang JC, Chen S, Yao NT, Du J, Gong HY. Advances in chiral carbon-rich molecules incorporating five-membered carbocycles since 2019: Fullerenes, nanographenes, and non-fully conjugated PAHs. Chiral Chem. 2027;3:202631. https://doi.org/10.70401/cc.2026.0042
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Wu ZH, Wang JC, Chen S, Yao NT, Du J, Gong HY. Advances in chiral carbon-rich molecules incorporating five-membered carbocycles since 2019: Fullerenes, nanographenes, and non-fully conjugated PAHs. Chiral Chem. 2027;3:202631. https://doi.org/10.70401/cc.2026.0042
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