Polycyclic Aromatic Hydrocarbons and Polycyclic Aromatic Sulfur Heterocycles: Examination of Molecular Structure-Fluorescence Probe Character Correlations

Abstract

Fluorescence emission spectra are reported for 1,6-dithiapyrene, 3,10-dithiaperylene, 1,7-dithiaperylene, thianthrene, benz[4,10]anthra-[1,9,8abcd]coronene, and benzo[cd]chryseno [4,5,6,7fghijk] perylene dissolved in several nonelectrolyte solvents of varying polarity. Emission spectra of the four polycyclic aromatic sulfur heterocycles (PASHs) contained very little fine structure. Severe spectral distortion, along with significant band broadening, was often observed in the case of PASHs dissolved in polar solvents. Benz[4,10]anthra[1,9,8abcd]coronene showed some probe-like character as evidenced by selective emission intensity enhancement of band I in dimethyl sulfoxide as compared to n-hexadecane solvent. The ratio of emission intensities for benz[4,10]anthra-(1,9,8abcd]coronene, however, failed to vary systematically with solvent polarity. Results of these fluorescence measurements indicate that all six solutes are unsuitable for solvent polarity probes.