On-surface synthesis of polyazulene with 2,6-connectivity

Azulene, the smallest neutral nonalternant aromatic hydrocarbon, serves as not only a prototype for fundamental studies but also a versatile building block for functional materials because of its unique opto(electronic) properties. Here, we report the on-surface synthesis and characterization of the homopolymer of azulene connected exclusively at the 2,6-positions using 2,6-diiodoazulene as the monomer precursor. As an intermediate to the formation of polyazulene, a gold-(2,6-azulenylene) chain is observed.