Design and Synthesis of Ethynyl-Linked Oligomers Emitting Variously Colored Fluorescence

In this paper, by means of forming alternately broad-narrow band gap unit in the backbones of polymers to regulate polymer light-emitting color, a series of ethynyl-linked alternating aromatic ring oligomers (P1, P2, P3 and P4) were designed and prepared by Sonogashira coupling polycondensation. These polymers have M_w 35524–12852 in moderate yields (35–67%). The influence of this kind of polymer’s structures on the optical properties was studied in detail with ¹H NMR,¹³C NMR, FTIR, UV, FL, CV, TGA, and fluorescence lifetime test. The results showed that these polymers exhibited good solubility, high thermal stabilities, high oxidative stability, stable optical properties and emitted variously colored fluorescence in moderate quantum yields (28–61%) due to their different energy gap. The fluorescence lifetimes of the polymers P1, P2, P3, and P4 were 0.8974, 1.695, 1.728, and 0.5929 ns, respectively. And the values of lifetime decrease with increasing solvent polarity. The effective light-emitting color regulation of poly(aryleneethynylene)s was realized by Gaussian calculation and experiment results.