Polymer, Vol.84, 65-71, 2016
Synthesis, characterization, optical and electrochemical properties of spirobifluorene based polymers containing electron deficient moieties
2,7-linked or 2,2'-linked 9,9'-spirobifluorene based polymers containing electron deficient moieties such as naphthalene bisimide and/or benzothiadiazole were synthesized through Suzuki cross-coupling reaction. The molecular weights of the copolymers containing spirobifluorene and benzothiadiazole units are relative low due to the low solubility of the resulting polymers. In addition, all polymers derived from 2,2'-linked 9,9'-spirobifluorene and naphthalene bisimide and/or benzothiadiazole showed very low molecular weights due to the low reactivity of the active species. The UVevis absorption spectrum of the polymers containing 2,7-linked 9,9'-spirobifluorene and naphthalene bisimide exhibited the longest absorption wavelength and very low quantum yield. Alternating polymers containing spirobifluorene and naphthalene bisimide moieties showed a low band gap relative to that of the spirobifluorene and benzothiadiazole containing polymers and their random copolymers presumably there is a strong charge transfer interaction between the alternating electron-donating spirobifluorene unit and the electron-accepting naphthalene bisimide. (C) 2015 Elsevier Ltd. All rights reserved.