SPECTROSCOPIC PROPERTIES OF POLYCYCLIC AROMATIC-COMPOUNDS .2. FLUORESCENCE EMISSION AND QUENCHING BEHAVIOR OF SELECT ACENAPHTHYLENE DERIVATIVES IN ORGANIC NONELECTROLYTE SOLVENTS

Fluorescence emission spectra have been measured for acenaphthylene, a ceanthrylene, acephenanthrylene, benz[e]aceanthrylene, 3-methylbenz[j] aceanthrylene, 6-methylbenz[j]aceanthrylene, benzo[def]cyclopenta[hi]c hrysene, cyclopenta[cd]pyrene (also called acepyrylene) and acenaphth[ 1,2a]acenaphthylene in organic nonelectrolyte solvents of varying pola rity. Benz[e]aceanthrylene was found to exhibit probe character for ma ny of the solvents considered; however, emission intensity ratios in b enzene, toluene, p-xylene and o-xylene were too small compared against nonelectrolyte solvents of similar polarity. The effect of nitrometha ne as selective quenching agent was also examined. Results of these me asurements show that nitromethane does quench the fluorescence emissio n of the nine solutes studied, which is contrary to what would be expe cted based upon the fact that all nine solutes are nonalternant polycy clic aromatic hydrocarbons.