SPECTROSCOPIC PROPERTIES OF POLYCYCLIC AROMATIC-COMPOUNDS .4. EFFECT OF SOLVENT POLARITY AND NITROMETHANE ON THE FLUORESCENCE EMISSION BEHAVIOR OF SELECT BIPOLYCYCLIC AROMATIC-HYDROCARBONS

Fluorescence emission behavior is reported for 1,1'-binaphthalene, 2,2'binaphthalene, 9,9'-bianthracene, 9,9'-biphenanthrene, 1,1'-methylene-bisnaphthalene, and 1,1',2,2'-tetrahydro-5,5'-biacenaphthylene dissolved in organic nonelectrolyte solvents of varying polarity, refractive index, and dielectric constant. Fluorescence measurements are used to classify the six bipolycyclic aromatic hydrocarbon (bi-PAH) solutes as either solvatochromic probe or nonprobe molecules, depending upon whether measured fluorescence properties vary with solvent nature. Of the bi-PAHs studied, only 9,9'-bianthracene exhibited probe character. Possible correlations between 9,9'-bianthracene's maximum intensity emission wavelength and select functions of solvent refractive index and dielectric constant were examined. Also reported is the effect that nitromethane has on bi-PAH fluorescence emission intensities.