POLYCYCLIC AROMATIC HYDROCARBON SOLUTE PROBES .11. UNUSUAL SOLVENT-MODULATED FLUORESCENCE EMISSION BEHAVIOR OF 1-METHYLCORONENE AND SELECT DIMETHYLCORONENES IN NONELECTROLYTE SOLVENTS

Fluorescence emission spectra are reported for 1-methylcoronene, 1,2-d imethylcoronene, 1,4-dimethylcoronene, 1,6-dimethylcoronene, 2,3-dimet hylcoronene, and 2,5-dimethylcoronene dissolved in organic nonelectrol yte solvents of varying polarity. Four of the five coronene derivative s were found to exhibit probe character, as evidenced by a systematic variation in emission intensity ratio with solvent poplarity. Mathemat ical expressions which correlate measured intensity ratios and solvent polarity probe behavior of 1-methylcoronene and 1,2-dimethylcoronene with pyrene in 46 solvents of varying polarity are reported. Also repo rted is the preferential solvation behavior of both solutes in binary mixtures of n-heptane + tetrahydrofuran and n-heptane + 1,4-dioxane.