Synthesis of polyacene: exceeding the limits of benzene rings extension

The acene series, an important class of linearly polycyclic aromatic hydrocarbons, are of significant interest owing to their unique physicochemical features. With an increase in the number of fused benzene rings, acenes display an evolution of electronic structure and properties. Thus, tremendous efforts have been devoted to the synthesis of longer acenes, reaching dodecacene being the longest acene (12-fused benzene rings) reported to date. However, the formation of polymeric acenes with numerous benzene rings, namely polyacene (PA), has yet to be realized. Herein, we present a methodology for the synthesis of PA, as a long-sought-after compound, mediated by a metal−organic framework (MOF). Nanoconfined synthesis of precursor polymers in MOF channels and the subsequent dehydro-aromatization reaction produced PA that was overwhelmingly longer than the previously reported acenes. The scalable synthesis of PA could allow us to unveil the stability and electronic properties of PA, paving the way for their widespread applications in both the scientific and industrial fields.