Siloles and Acetenyl Aromatics Copolymers: Synthesis, Characterization and Photophysical Properties

Two copolymers, poly(1,1-dimethyl-3,4-diphenylsilole-alt-N-hexyl-3,6-diethynylcarbazole) (PS-DyCz) and poly(1,1-dimethyl-3,4-diphenylsilole-alt-2,7-diethynyl-9,9-dihexylfluorene) (PS-DyF), were synthesized by Sonogashira coupling reaction of 2,5-dibromo-1,1-dimethyl-3,4-diphenylsilole and N-hexyl-3,6-diethynylcarbazole or 2,7-diethynyl-9,9-dihexylfluorene, respectively. The chemical structures of the copolymers were characterized by NMR, FT-IR techniques. Their thermal and photophysical properties were evaluated by TGA, DSC, UV-Vis and fluorescence spectroscopy, respectively. The weight-averaged molecular weights (M-w) of PS-DyCz and PS-DyF are 1.20x10(4) and 3.83x10(4) Da, respectively. The degree of polymerization is 8 and 22 units. These -conjugated polymers exhibited lower band-gap of 2.25 and 2.70 eV due to the presence of silole rings and CC triple bonds in their backbone, the results were consistent with the density functional (DFT) calculations at the B3LYP/6-31G* level.