Resonance raman spectroscopy and vibrational analysis of poly(isothianaphthene) and related compounds

Vibrational Spectroscopic Study of Iodine-Doped Poly(Isothianaphthene)

“…All the m ajor bands and their assignments are listed in Table I. The band positions are consistent with the published studies, 1,11,12,23,24 except for the band at 1680 cm 2 1 , which is assigned to -C5O stretching. Carbonyl group formation at the ends of the polymer chains m ay occur during the O 2 induced polymerization, as has been previously reported, 25 and further details will be published separately.…”

“…Far-infrared peaks of undoped PITN are observed at the following wavenumbers: 190(w) and 434(s) cm 2 1 , as previously reported for PITN. [11][12][13] Additional weak peaks were observed at 93(w), 243(w), and 388(w) cm 2 1 . Upon iodine doping, a new peak at 135 cm 2 1 appeared, which is assigned to the n 3 m ode of I 3 2 .…”

“…The Raman bands of undoped PITN powders are very similar to the Raman spectra recorded by using 514.5-nm excitation, except that the peak arising from the -C5C-stretch shifts to 1474 cm 2 1 due to the dispersion of conjugated chain lengths. 12,41 Iodine doping produces signi cant changes to the spectra in the 350 -500, 1100 -1200, and 1300 -1500 cm 2 1 regions. New peaks appear and their relative intensities change upon iodine doping.…”

“…1 The special properties of this polymer are its low band gap (E g ø 1 eV), 2 and its nearly colorless transparency upon doping. 3,4 Vibrational spectroscopy has proved to be a useful method for the study of the effect of doping on polymer lms, the structure of electronically conductive polymer lms of polyacetylene, 5 polypyrrole, [6][7][8] polythiopthene, 9,10 and poly(isothianaphthene), [11][12][13] and it is also sensitive to the structural changes arising from the creation of polarons and bipolarons upon doping. Doping generates electronic defects by rem oval or addition of electrons and produces new electronic states within the band gap of the polymer.…”

“…These states give rise to new absorption bands in the visible or NIR regions, and vibrations associated with the defects can be observed by Raman spectroscopy. 14 The processes of electrochemical oxidation and reduction of polymer lms have been investigated in detail, [5][6][7][8][9][10][11][12][13] but the chemical oxidation and reduction of PITN powders have attracted much less attention despite the potential importance of this form of the polymer. It is not well established whether the difference in m orphology between lms and powders will affect the properties of doped EXPERIMENTAL M aterials.…”