Naphthylene-γ: 1D and 2D carbon allotropes based on the fusion of phenyl- and naphthyl-like groups

Graphenylene and naphthylene have recently been proposed as two-dimensional carbon allotropes conceptually defined by the assembly of phenyl-like (P) or naphthyl-like (N) units with the creation of side squarelike rings. These structures can be cut into one-dimensional (1D) nanoribbons displaying electronic properties ranging from metals to semiconductors. Even though they have not been synthesized to date, recent advances in preprogrammed atomically precise chemical routes are compatible with their future synthesis. Here, an alternative naphthylene form is proposed. It is named as the $\ensuremath{\gamma}$ type, which is theoretically constructed by combining P and N blocks joined by 4-membered links. This naphthylene-$\ensuremath{\gamma}$ has a semiconductor behavior and theory predicts that this property is shared by its nanoribbon counterparts. Computational analysis also indicates the electronic structure of these systems is dictated by quasi-1D states due to the interplay between the system's geometry (e.g., chirality and edge structure) and its electronic properties.