Preparation of a germole-containing π-conjugated polymer by the Te–Li exchange reaction of a tellurophene-containing polymer

Abstract

Abstract The synthesis and optoelectronic functions of a germole-containing π-conjugated polymer prepared by the reaction of a lithiated polymer precursor are described. A regioregular organometallic polymer having 1,4-dilithio-1,3-butadiene and 9,9-dioctylfluorene-2,7-diyl units was generated by the reaction of a tellurophene-containing polymer having a number-average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of 5900 and 1.9, respectively, with n-butyllithium (2.4 equiv) at −78 to −60 °C for 3 h. The prepared lithiated polymer was reacted with dimethylgermanium dichloride (1.5 equiv) at −60 °C to ambient temperature for 12 h in tetrahydrofuran to produce a π-conjugated polymer possessing 1,1-dimethylgermole-2,5-diyl units in 76% yield (Mn = 4400 and Mw/Mn = 1.7). The absorption maximum and onset of the obtained polymer were observed at 465 and 535 nm, respectively, in the UV-vis spectrum, from which the optical band gap of the polymer was estimated to be 2.31 eV. In the photoluminescence spectrum, the obtained polymer exhibits green fluorescence with an emission maximum of 547 nm and a quantum yield of 0.04. The chemical interaction of the dimethylgermole-containing π-conjugated polymer with fluoride was also examined in terms of the changes observed in the UV-vis absorption spectra.