The recent successful preparation
of infinitene has sparked
widespread
attention due to its aesthetic appeal and synthetic challenge. Spectroscopic
measurements and follow-up computational investigations suggest that
infinitene holds fundamental significance and potential applications
in chiroptics, optoelectronics, asymmetric synthesis, and supramolecular
chemistry. However, unlike other looped polyarenes enriched with sizes
and shapes, the infinitene molecule seems, so far, the only known
example of this fascinating new form of nanocarbons, whose further
exploitation would be considerably limited because of the lack of
molecular diversity. Here, we introduce a whole new family of generalized
infinitenes with different sizes and topologies. Three types of infinitene
structures are rationally designed by joining two units of coronene,
kekulene, or their extended analogs. The constructed molecules of
varying sizes, each with a large number of possible topoisomers, are
systematically studied by DFT calculations. Comprehensive analysis
using a simple energy decomposition model uncovers that the stability
of infinitenes is governed by the interplay among π delocalization,
steric strain, and π–π stacking. While the first
two factors are crucial to the stability of smaller infinitenes, the
latter is the primary stabilizing interaction for larger infinitenes.
Most importantly, we show that larger-sized infinitenes are actually
the energetically most favorable form among all known looped polyarenes;
their substantial thermodynamic stability surpassing that of circulenes,
various carbon nanobelts, and kekulene-like macrocycles renders them
promising targets for synthesis. The simulated 1H NMR,
UV–vis, and circular dichroism spectra along with optical rotations
for the most stable infinitene species may help their identification
in future synthetic efforts.