Polycyclic Aromatic Nitrogen Heterocycles. Part IV: Effect of Solvent Polarity, Solvent Acidity, Nitromethane and 1,2,4-Trimethoxybenzene on the Fluorescence Emission Behavior of Select Monoaza- and Diazaarenes
Fluorescence emission spectra are reported for naphth[2',1',8',7':4,10,5]anthra[1,9,8cdef]cinnoline, benzo[lmn][3,8]phenanthroline (also called 2,7-diazapyrene), benz[4,10]anthra[1,9,8cdef]cinnoline, naphtho[8,1,2hij]pyreno[9,10,1def]phthalazine, acenaphtho[1,2b]pyridine, benzo[a]phenazine,
indeno[1,2,3ij][2,7]naphthyridine, and indeno[1,2,3ij]isoquinoline dissolved in organic nonelectrolyte solvents of varying polarity and acidity. Results of these measurements indicate that naphth[2',1',8',7':4,10,5]anthra[1,9,8cdef]cinnoline exhibits some signs of probe character as evidenced
by changing emission intensity ratios; however, numerical values did not vary systematically with solvent polarity. The effect of nitromethane and 1,2,4-trimethoxybenzene as selective quenching agents on both the unprotonated and protonated PANHs was also examined. Nitromethane was found to
quench fluorescence emission of roughly two-thirds of the alternant unprotonated PANHs studied to date. Emission intensities of the protonated PANHs remained essentially constant and were not affected by nitromethane. 1,2,4-Trimethoxybenzene, on the other hand, quenched the fluorescence emission
of several unprotonated and all protonated PANHs examined.
Document Type: Research Article
Department of Chemistry, University of North Texas, Denton, Texas 76203-5068, U.S.A.
Rütgerswerke AG, Kekulestrasse 30, D-4620 Castrop-Rauxel, Germany
Physical Chemistry Laboratory, Swiss Federal Institute of Technology, Universitätstrasse 22, CH-8092 Zurich, Switzerland
SRI International, 333 Ravenswood Avenue. Menlo Park, California 94025, U.S.A.
Department of Applied Chemistry, Saitama University, Shimo-Ohkubo, Urawashi 338, Japan
Publication date: November 1, 1992
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