Synthesis And Properties Of Conjugated Polymers Containing Difuranyl Substituted Acenaphthenequinoxaline

Preparation and studies of new conjugated polymers have attracted considerableattention due to their unique optoelectronic properties and application inopto-electronic devices. Quinoxaline is a typical electron deficient aromaticcompound, it can formate charge transfer conjugated polymers with electron richaromatic ring such as thiophene,pyrrole and furan.Polymers containing quinoxalinewere studied extensively, but containing aromatic fused ring, especially side chaincontaining planar ring quinoxaline copolymerized with electron rich aromatic ring arerarely studied. Our research group reported dithiophene subsititutedacenaphthoquinoxaline(DThQx(ace)) conjugated polymers anddiethylenedioxythiophene subsituted acenaphthoquinoxaline(DEDOTQx(ace))conjugated polymers and they have good electrochemical activities. While difuranacenaphthoquinoxaline conjugated polymers were not studied.Synthesis of difuransubsitituted acenaphthoquinoxaline conjugated polymers has a certain theoreticalmeaning so as to systematic study of different electron rich aromatic ring subsititutedacenaphthoquinoxaline conjugated polymers and further study of differentsubsititutents effects on resulted polymer properties. In this paper difuran subsitutedacenaphthoquinoxaline conjugated polymers were prepared. And their structures andproperties were characterized by FTIR,¹HNMR, ultraviolet-visible (UV-vis)absorption spectra, photolumiscent (PL) spectra, cyclic voltammetry(CV),galvanostatic charge–discharge measurements and X-ray diffraction (XRD). The mainresults are as follows:1. A new monomer difuran subsitituted acenaphtho[1,2-b] quinoxaline (DFuQx(ace))was synthesized by Stille coupling reaction. Uv-vis absorbance of monomerappeared at325and436nm in CHCl₃and332nm,560nm in CF₃COOH(TFA)respectively, PL emission peaks appeared at551nm in CHCl₃; the XRD resultshowed that monomer has crystallization trend when solvent naturally evaporated.2. Poly5,8-bisfuranylacenapthoquinoxaline was synthesized with differentmonomer/oxidant ratio in anyhydrous chloroform medium. Polymer maximumyield of98%when monomer/oxidant ratio1:8. Iodene dopping levels werearound70%⁸3.9%, corresponding coductivity have also rised. Polymers wereinsoluble in common organic solvents, P₁and P₂were partly soluble in TFA andUV-vis absorption band appeared at750nm and650nm respectively.3.Monomer was brominated and copolymrized with1,4-Diethynyl-2,5-dialkoxybenzene by Sonogashira reaction.Resulted copolymer PⅠand PⅡwere soluble inTHF, cloroform and toluene. Maximum absorbance of longer wavelengthappeared at418and423nm, corresponding emission peaks appeared at589and579nm respectively; The CV result show that copolymers have maximumoxidation peaks of1.54V at the same potential, and exhibit irreversibleelectrochemical activities.4.5,8-bisfuranyl acenaphthoquinoxaline and fluorene alternating copolymer wereprepared by Suzuki reaction and maximum absorbance of longer wavelengthappeared at474nm, corresponding emission peaks appeared at564nm. Thecopolymers have maximum oxidiation peaks appeared at1.69V.