Synthesis of polyacene by using a metal-organic framework

The acene series, an important class of linearly polycyclic aromatic hydrocarbons, are of 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, efforts have been devoted to the synthesis of longer acenes, with dodecacene being the longest acene (12 fused benzene rings) reported to date. However, the formation of polymeric acenes with numerous benzene rings, namely polyacene, has yet to be realized. Herein, we present a methodology for the synthesis of polyacene mediated by a metal-organic framework. Nanoconfined synthesis of precursor polymers in the channels of the metal-organic framework and the subsequent dehydro-aromatization reaction produced polyacene that was overwhelmingly longer than the previously reported acenes. The scalable synthesis of polyacene allowed us to unveil the stability and electronic properties of polyacene, paving the way for their widespread applications in optoelectronic and magnetic devices. Elongation of acenes with linearly fused benzene rings is a synthetic challenge. Now, the use of a metal-organic framework enables the synthesis of polymeric precursors, which undergo thermal transformation to form polyacenes.