Abstract
A combined solution and solid state study was performed to describe the complexation chemistry of iodine with three highly fluorescent bis-1,8-naphthalimide dyes. The spectroscopic properties, photostability characteristics and the mechanism of interaction were investigated and discussed. The formed complexes were characterized stoichiometrically and structurally using ultraviolet-visible, mid- and far-infrared spectral techniques, as well as CHN elemental analyses. A remarkable change in the UV-Vis spectra was observed when the iodine acceptor was complexed with a 1: 2 stoichiometry. Far-IR measurements confirmed the formation of triiodide (I-3(-)). The formation constant, molar extinction coefficient and other spectroscopic data were also determined and discussed. It has been found that the complexation with iodine increases the photostability of the reported dyes. Interestingly, a strong linear correlation (r = 0.991) between half-life of photostability and dissociation energy in solution is clearly evidenced for the first time.