Direct synthesis of polyaromatic chains of tribenzopentaphene copolymers through cyclodehydrogenation of their poly-tetraphenylbenzene precursors

Three polyaromatic-based polymers are reported to contain co-monomers of trapezoidal tribenzopentaphene (TBP) polycyclic aromatic hydrocarbons. The synthetic strategy consists of initially making highly soluble tetraphenylbenzene copolymers 4a–c, followed by a cyclodehydrogenation/aromatization reaction to obtain target polymers 5a–c. The polymers were characterized by gel permeation chromatography, FT-IR, UV-vis, emission, ¹H-, and ¹³C-nuclear magnetic resonance spectroscopy. The target polymers 5a–c reveal emission spectra in the range of 430–480 nm; thus, qualifying them to act as blue emitters. Investigation of the polymers optical properties and their correlation with density functional theory calculations suggest a distorted TBP core from planarity caused by the introduction of a dodecyl group at its wide edge.