Poly(tetrafluorobenzo[c]thiophene). Structure analysis of oligomers and model compound based on 1D and 2D NMR spectroscopy

In order to help provide a more detailed structural analysis of poly(4,5,6,7-tetrafluorobenzo[c]thiophene), a series of aromatic fluorinated oligomers (n = 1-4) and 1,3-dithienyl-4,5,6,7-benzo[c]-thiophene have been synthesized. Structure analysis of these compounds by means of 1D and 2D NMR techniques provides a set of spectroscopic NMR data which can be considered as characteristic for the aromatic structure of the corresponding polymer. In addition to F-19-decoupled C-13 NMR spectroscopy and attached fluorine tests, the method of full chemical shift assignment based on two-dimensional H-1-C-13 heteronuclear correlation (HETCOR) experiments optimized for J(CH) = 140 HZ and J(CH) = 8 HZ was extended with two-dimensional F-19-C-13 heteronuclear correlation (HETCOR) experiments optimized for J(CF) = 255 Hz and J(CF) = 45 Hz and F-19-F-19 homonuclear correlation spectroscopy (COSY).