Synthesis and photoluminescence of linear and hyperbranched polyethers containing phenylquinoxaline units and flexible aliphatic spacers

Abstract

Ultrahigh-molecular-weight linear polyethers were prepared through a reaction between the phenylquinoxaline monomers 2,3-bis(4-hydroxyphenyl)-6- fluoroquinoxaline and 2,3-bis(4-hydroxyphenyl)-6-(α,α,α- trifluoromethyl)quinoxaline and 1,12-dibromododecane. A new hyperbranched polyether containing a phenylquinoxaline moiety was also prepared from a new self-polymerizable AB 2 monomer, 2,3-bis(6-bromohexyloxyphenyl)-6-(4- hydroxyphenyloxy)quinoxaline. All the polyethers were amorphous and soluble in polar aprotic solvents. Their solution-cast thin films were light yellow, ductile, and optically transparent. The polymers were thermally stable up to 350°C and had glass-transition temperatures in the range of 25-83°C, which depended on the architecture and monomer structure. The monomers and polymers displayed fluorescence maxima in the blue-light region in the range of 431-449 nm with relatively narrow peak widths; this indicated that they had pure and intense fluorescence.