Synthesis and fluorescent properties of conjugated copolymers containing maleimide and fluorene units at the main chain

Abstract

Yamamoto or Suzuki-Miyaura coupling polymerizations of 2,3-diiodo-N-cyclohexylmaleimide with fluorene derivatives (2,7-dibromo-9,9 0 -dihexylfluorene and 9,9 0 -dihexylfluorene-2,7-diboronic acid) were carried out. The numberaverage molecular weights (M n ) of the resulting copolymers were 2600-3500 by gel permeation chromatography analysis. The fluorescence emission of the alternating copolymer showed the emission maxima at 551 nm in THF. On the other hand, the random copolymers showed the bimodal emission peaks at 418-420 and 555-557 nm region, respectively. The fluorescence peaks of the random copolymers on the long wavelength region (555-557 nm) were attributed to the conjugated neighboring N-cyclohexylmaleimide-9,9 0 -dihexylfluorene units in the polymer main chain. Furthermore, the copolymers exhibited the fluorescence solvatochromism by the difference of the polarity of solvents. The alternating and random copolymers showed the different fluorescence solvatochromism, and the emission colors are distinguishable by the naked eye, respectively.

Synthesis and photophysical properties of blue emission maleimide molecules with dual-state emission (DSE) effects

“…The introduction of substituents with varying electronic effects enables effective tuning of the optical band gap, resulting in different luminescent colors. [35][36][37][38] Moreover, it also boasts good chemical stability and high fluorescence intensity. Due to these advantages, maleimidebased dyes are extensively utilized in various domains.…”

Enhanced thermo-stability and luminecent property of D-A copolymer based on fluorene and thieno[3,4-c]pyrrole-4,6-dione by incorporation of pentafluorobenzene group

“…As a result, copolymerization of fluorene with the other co-monomer becomes an alternative method for tuning the optical, electronic, and thermal properties. 17,18 The dominant strategy has been to design copolymers with alternating the electron-rich or electron-deficient units. To achieve a full-color flat display, three primary-color (i.e., blue, green, and red) light emitting materials with narrow emitting spectra are required.…”