IR Spectroscopy of Pristine and Iodine-Doped Permethylpolyazine
William B. Euler, Chemistry of Materials, 1996, 8, 554 – 557
Abstract
Mid and near IR spectra for pristine and iodine-doped permethylpolyazine (-[N=C(CH3)-C(CH3)=N]x-) are reported for both natural isotopic abundance and 100% 15N enriched samples. For the undoped samples the degree of conjugation along the polymer backbone is fairly small. Upon exposure to iodine, the only changes in the IR spectra are found in the near IR where a very intense band grows in above 4000 cm–1 and in the mid IR where there is development of a weaker, poorly resolved doublet around 1500 cm–1. The strong absorption in the near IR has none of the characteristics normally associated with gap states so is assigned to be the tail of the visible, electronic absorption of triiodide. The doping-induced feature in the mid IR is a doublet; the higher energy band is diminished upon 15N enrichment while the lower energy peak is unaffected by the isotopic substitution. Complexation of I+ to the polymer, probably through the imine pi bond, is thought to be responsible for the new mid IR peaks. There is no evidence that the polymer has been oxidized.