Graphene-like Molecules with Four Zigzag Edges

An efficient synthetic method toward graphene-like molecules (GLMs), having four zigzag edges, is described. They were obtained as stable materials and their structures were confirmed by X-ray crystallographic analysis. They exhibit topology- and size-dependent electronic properties and global aromaticity, which are all different from GLMs having either all-armchair edges, or three zigzag edges, or two armchair/two zigzag edges. They can be reversibly oxidized and reduced into stable charged species, which show fragmental aromatic character to minimize anti-aromaticity. Our studies give some new insights into the electronic structures and properties of a new type of rarely studied GLMs.