Spectroscopic Investigation of Fluorescence Quenching Agents: Effect of Nitromethane on the Fluorescence Emission Behavior of Select Cyclopenta-PAH, Aceanthrylene, and Fluorene Derivatives

Nitromethane is examined as a selective fluorescence quenching agent for “alternant” alkyl-substituted polycyclic aromatic hydrocarbons (PAHs). Fluorescence emission behavior is reported for 11 H-benz[bc]aceanthrylene, 4 H-cyclopenta[def]phenanthrene, 4 H-cyclopenta[def]chrysene, 13 H-dibenzo[a,g]fluorene, 13 H-dibenzo[a,i]fluorene, 4 H-benzo[b]cyclopenta[mno]chrysene, 4 H-cyclopenta[pqr]picene, 7 H-dibenzo[c,g]fluorene, 9 H-benz(6,7)indeno[1,21]phenanthrene, 4 H-benzo[b]cyclopenta[jkl]triphenylene, 13 H-dibenz[bc,k]aceanthrylene, 13 H-dibenz[bc,l]aceanthrylene, and 4 H-benzo[def]cyclopenta[mno]chrysene dissolved in organic solvents of varying polarity and in acetonitrile or aqueous-acetonitrile solvent mixtures at various nitromethane concentrations. Results of these measurements show that nitromethane quenches fluorescence emission of the thirteen solutes studied, which is in complete agreement with what would be expected on the basis of the fact that all solutes are “alternant” polycyclic aromatic hydrocarbons.