On the quinoiid structure of poliisothionaphtene: a spectroscopic study

Summary form only given. The issue on whether Poliisothionaphtene (PITN) has a quinoid or aromatic structure is still debated. Several quantum chemical calculations have been presented. This work represent an experimental approach to the problem. Several model molecules which force either the quinoid or the aromatic structure have been synthesized. The vibrational spectra (infrared and Raman) have Jeen used as the structural probe; the analysis of the Raman spectra is based on the theory of the Effetive Conjugation Coordinate. The evidence collected suggests that in its gound electronic state PITH has a quinoid structure.