The Sequential C ₂ Addition Formation Mechanism of [6,6] Fullertube C ₃₆₊₃₆₊₁₂ n Series: A Theoretical Study

Stimulated by the experimental observation of fullertube [ Journal of the American Chemical Society . 2020, 142 , 15,614–15,623], a systematic density functional study of the structures and the growth pathway of [6] fullertube C 36+36+12 n series is performed. Starting from D 6d (1)–C 72 , D 6h (24)–C 84 can be described as consisting of two end‐caps (half of D 6d (1)–C 72 ) attached to a C 12 carbon ring. Potential energy surface calculations reveal that the optimal pathway for this growth process proceeds via six sequential and directional C 2 insertions involving metastable heptagonal‐ring intermediates and avoiding high‐energy‐barrier Stone–Wales rearrangements. These findings offer critical insight into the self‐assembly mechanism of fullerene‐based nanostructures and establish a theoretical basis for the rational design of tunable carbon nanomaterials.