Spectroscopic Properties of Polycyclic Aromatic Compounds: Examination of Nitromethane as a Selective Fluorescence Quenching Agent for Alternant Polycyclic Aromatic Nitrogen Hetero-Atom Derivatives

Abstract

Nitromethane is examined as a selective fluorescence quenching agent for alternant polycyclic aromatic nitrogen hetero-atoms (PANHs). Fluorescence emission behavior is reported for 1-azapyrene, 2-azapyrene, 4-azapyrene, 4-azachrysene, 12-azabenzo[a]pyrene, phenanthro[9, 10g]isoquinoline, phenanthro[2,3h]isoquinoline, phenanthro[3,2h]-isoquinoline, 2-azabenz[a]anthracene, 1-azabenz[a]anthracene, 9-azabenz[a]anthracene, dibenzo[c,i]phenanthro[1,10,9,8anmlk]phenanthridine, diphenanthro[9,10,1def;1',10',9'hij]phthalazine, and benz[de]isoquino[1,8gh]quinoline dissolved in acetonitrile or aqueous-acetonitrile solvent mixtures at various nitromethane concentrations. Results of these measurements show that nitromethane does quench fluorescence emission of ten of the solutes studied; however, phenanthro-[2,3h]isoquinoline, 9-azabenz[a]anthracene, benz[de]isoquino[1,8gh]-quinoline, and dibenzo[c,i]phenanthro[1,10,9,8anmlk]phenanthridine are notable exceptions.

A Three-Step Synthesis of 1,7-Diazaperylene and Derivatives

“…Electron-deficient aromatic systems are arousing increasing interest 1 as electron acceptors in organic electronics 2 such as organic 3 photovoltaics. 4,5 1,7-Diazaperylene (1) (benz [de]isoquino [1,8-gh]quinoline, CAS RN 85903-97-5) 6 was the subject of several investigations in this field [7][8][9] because of its high fluorescence quantum yield (83%) 10 and appreciable chemical and photochemical stability. The planar heteroaromatic molecules are densely packed ( cryst = 1.42 Mg•m -3 ) forming a modified herringbone structure.…”

Synthesis and Properties of Benzo[h]imidazo[1,2-a]quinolines and 1,2a-Diazadibenzo[cd,f]azulenes

“…3, 133.4, 133.4, 132.4, 130.9, 130.1, 129.2, 128.7, 128.5, 127.8, 127.4, 127.3, 126.8, 126.5, 124.8, 122.6, 121.2, 117.3, 117.0, 21.6. MS (GC): m/z (%) = 310 (3), 309 (25), 308 (M + , C 22 H 16 N 2 , 100), 307 (25), 306 (5), 305 (4), 303 (2), 294 (5), 293 (21), 292 (8), 291 (3), 290 (1). HRMS (ESI-TOF) m/z: [M + H] + calcd for C 22 H 17 N 2 , 309.1392; found, 309.1389.…”

Polycyclic Aromatic Nitrogen Heterocycles. Part V: Fluorescence Emission Behavior of Select Tetraaza- and Diazaarenes in Nonelectrolyte Solvents

“…Various emission intensity ratios of 1-azapyrene, 2-azapyrene, 4-azapyrene, 4-azachrysene, benzo[lmn]- [3,8]phenanthroline, and benzo [4,10]anthra [1,9,Scdef]-cinnoline remained constant, irrespective of solvent polarity. Fluorescence emission spectra of benzo[a]-phenazine, acenaphtho [1,2]pyridine, indeno [1,2,3ij]-isoquinoline, and indeno [1,2,3ij] [2,7]naphthyridine showed very little structured emission. Depending upon the solute and solvent combination being studied, either one unsymmetrical band or two poorly resolved peaks were observed.…”