Synthesis, Structures, and Properties of Polybenzo[n]spirenes With Carbon-based Polyspiroconjugation

One-dimensional (1D) carbon-based polyspiroconjugated molecules, polybenzo[n]spirenes (n = 1–4), were synthesized using a simple and iterative synthetic protocol starting from anthraquinone. Polybenzo[n]spirenes possess one-dimensionally connected polyspirene cores with structures slightly distorted owing to peripheral benzo fusions. Because of the compact spiro-carbon centers, the surrounding p-orbitals are orthogonal yet overlap significantly, ena- bling effective 1D-aligned polyspiroconjugation. As a result, the polybenzo[n]spirenes exhibited LUMO splitting and red shifted absorption and emission as the number of spiro structures increased.