Polycyclic Aromatic Nitrogen Heterocycles. Part VI. Fluorescence Emission and Quenching Behavior of Select Phenyl- and Alkyl-derivatives Dissolved in Nonelectrolyte Solvents

Fluorescence emission spectra are reported for tricycloquinazoline, dibenzo[c,f][2,7]naphthyridine, dibenzo[a,c]phenazine, dibenz[b,h]-indeno[1,2,3de][1,6]naphthyridine, and dibenz[c,f]indeno[l,2,3ij]-[2,7]naphthyridine dissolved in organic nonelectrolyte solvents of varying polarity and acidity. Results of these experiments were used to screen PANHs for potential probe character. The effect of nitromethane as a selective quenching agent on both the unprotonated and protonated PANHs was also examined. Nitromethane was found to quench fluorescence emission of dibenzo[c,f][2,7]naphthyridine. Emission intensities of the remaining four PANHs, and of the three protonated PANHs for which emission spectra could be obtained, remained essentially constant and were not affected by nitromethane.

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Polycyclic Aromatic Nitrogen Heterocycles. Part III: Effect of Solvent Polarity and Solvent Acidity on the Fluorescence Emission Behavior of Select Azapyrenes and Phenanthroisoquinolines

Applied Spectroscopy ◽

10.1366/0003702914336598 ◽

1991 ◽

Vol 45 (5) ◽

pp. 911-915 ◽

Cited By ~ 18

Author(s):

Sheryl A. Tucker ◽

William E. Acree ◽

Mary J. Tanga

Keyword(s):

Nitrogen Heterocycles ◽

Fluorescence Emission ◽

Solvent Polarity ◽

Effect Of Solvent ◽

Polycyclic Aromatic ◽

Emission Behavior ◽

Solvent Acidity

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Estimate of Hyperconjugation Strength in Alkylaromatics and Unsaturated Hydrocarbons Derived from Refractometric Data

Current Organic Chemistry ◽

10.2174/1385272823666191108100747 ◽

2020 ◽

Vol 23 (23) ◽

pp. 2598-2613

Author(s):

Boris A. Zaitsev

Keyword(s):

Quantitative Estimation ◽

Physical Phenomenon ◽

Unsaturated Hydrocarbons ◽

Resonance Effects ◽

Alkyl Derivatives ◽

Retrospective View ◽

Scientific Papers ◽

Polycyclic Aromatic ◽

Qualitative Measure ◽

Steric Inhibition Of Resonance

: A retrospective view of exaltation of refraction observed for many unsaturated and aromatic compounds demonstrates that this physical phenomenon is undeservedly considered only as a qualitative measure of conjugation. This mini-review discusses numerous papers by the author that have been published earlier in inaccessible periodicals and collections of scientific papers. Using a great number of illustrations, the author shows that this parameter can be successfully used for quantitative estimate of resonance effects in organic and polymer chemistry. The methods for derivation of strictly additive atomic and group refraction constants are described; these constants were subsequently used as a tool that allowed quantitative estimation of resonance effects in mono-, di-, tri- and polyalkylbenzenes, alkylnaphthalenes, some alkyl derivatives of unsaturated hydrocarbons. These effects cause strictly fixed increase in refraction of carbon atoms in different structural modifications (graphene, fullerene, diamond) and in polycyclic aromatic hydrocarbons. The relevant results regarding quantitative estimation of degree of steric inhibition of resonance in sterically hindered ortho-dialkylbenzenes, 1,2,3- trialkyl-, 1,2,3,4-tetraalkyl-, and 1,2,3,4,5-polyalkylbenzenes accumulated by the author are summarized.

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