Nonalternant Polycyclic Aromatic Hydrocarbons Research Articles

Chromatographic evaluation of some selected polycyclic aromatic hydrocarbons of coal tars produced under different coking conditions and pitches derived from them

The volatile fractions of carbon disulfide extracts in tars and pitches have been studied by gas chromatography (GC), using the stationary phase OV-1701. Major polycyclic aromatic hydrocarbons (PAHs) in the fractions were selected as a basis for assessment of differences in the compositions of tars associated with their production. Several coal tars produced by wet charging carbonization in industrial- and semi-industrial-scale ovens with different mean flue heating temperatures were analyzed. The effects of preheating coal at about 200°C prior to the coking process were also studied. From chromatographic data, ratios of different individual compounds or classes of compounds were calculated. They revealed that an increase in the carbonization temperature and coal preheating produced similar effects on tar and pitch composition, leading to a reduction in methyl-substituted PAHs, non-alternant PAH systems and highly reactive compounds such as acenaphthylene. A higher proportion of peri-condensed PAHs and PAHs with a higher degree of condensation were also observed. GC analysis provides an adequate method for estimating the degree of pyrolysis of tars in coke ovens and their thermal stability in pitch production.

Synthesis of the Diol Epoxide Metabolites of Carcinogenic PAH

Abstract The active metabolites of alternant carcinogenic polycyclic aromatic hydrocarbons (PAH) with 4-5 fused rings are now readily available through synthesis. Development of new synthetic methodologies that are more efficient and are also applicable to larger PAH and to nonalternant PAH will be discussed. Syntheses of the unusual diol epoxide metabolites of the methylene-bridged PAH 4H-cyclopenta[def]chrysene, in both unsubstituted and substituted bay regions will be described. The latter is the first example of diol epoxide in which the epoxide function is located in an alkyl-substituted bay region site. Syntheses will also be outlined of the large polyarene benzo[s]picene, and its fjord region dihydrodiol and diol epoxide metabolites via a novel route.

Effect that Various Electron Donating Functional Groups have Regarding Nitromethane's Inability to Quench Fluorescence Emission of Nonalternant Fluoranthenoid Polycyclic Aromatic Hydrocarbons

Abstract Nitromethane selectively quenches fluorescence emission of alternant polycyclic aromatic hydrocarbons (PAHs) via an electron transfer mechanism. Emission intensities of nonalternant PAHs, for the most part, are unaffected. To better understand the quenching mechanism, the fluorescence behavoir of 1-methylfluoranthene, 2-methylfluoranthene, 3-methylfluoranthene, 7-methylfluoranthene, 8-methylfluoranthene, t-butyldibenzo[ghi, mno]fluoranthene, 10-methylbenzo[b]fluoranthene, 12-methoxybenzo[b]fluoranthene, 10-methoxybenzo[b]fluoranthene, 10-hydroxybenzo[b]fluoranthene, 10-hydroxybenzo[j]fluoranthene, 10-methoxybenzo[j]fluoranthene, 3-metnoxybenzo[k]fluoranthene, 3-hydroxy-benzo[k]fluoranthene, 9-methoxybenzo[k]fluoranthene and 9-hydroxybenzo[k]fluoranthene dissolved in neat acetonitrile, toluene-acetonitrile and ethyl acetate-acetonitrile solvents was measured at different nitromethane concentrations. Experimental results show that electron donating methyl-, t-butyl, methoxy- and hydroxy-groups do not favorably alter the molecular orbital energies and/or reduction potentials so as to encourage electron transfer from the substituted nonalternant PAH molecule to nitromethane, which acts as the electron acceptor in the presumed quenching mechanism.

Effect that Various Electron Donating and Electron Withdrawing Functional Groups have Regarding Nitromethane's Ability to Selectively Quench Fluorescence Emission of Alternant Polycyclic Aromatic Hydrocarbons

Abstract Nitromethane selectively quenches fluorescence emission of alternant polycyclic aromatic hydrocarbons (PAHs) via an electron transfer mechanism. Emission intensities of nonalternant PAHs, for the most part, are unaffected. To better understand the quenching mechanism, the fluorescence behavior of 1-methylpyrene, 2-methylpyrene, 4-methylpyrene, 1,5-dimethylpyrene, 1-butylpyrene, 1-decylpyrene, 1-pyrenebutanoic acid, 1-chloropyrene, 1-aminopyrene, 3,4,5-trihydrobenzo[cd]pyrene, 1-pyrenecarboxaldehyde, 1,3-pyrenedicar-boxaldehyde, 3,6-dicyanobenzo[e]pyrene, 5,6,7,8,9,10-hexahydrobenzo[ghi]perylene, 4H-benzo[e]cyclopenta [1]pyrene, 3,4-dihydrobenzo[ghi]perylene, 4,5,6,7-tetrahydro-4,7-methanodibenzo[fg,op] naphthacene, 8b,9,10,11,12,12a-hexahydro-9,12-methanobenzo[e]pyrene, 5-methyldibenzo[b,def]chrysene, 5-methyl-chrysene, 4-methylchrysene, 2-methylanthracene, 9,9′-bianthracene-10-carboxaldehyde, 3-perylenecar-boxaldehyde, and 1-acetylcoronene dissolved in neat acetonitrile, toluene-acetonitrile and...

Selective fluorescence quenching to discriminate between alternant and non-alternant polycyclic aromatic hydrocarbons: acephenanthrylene derivatives as exceptions to the nitromethane quenching rule

Nitromethane selectively quenches the fluorescence emission of alternant polycyclic aromatic hydrocarbons (PAHs)via an electron transfer mechanism. Emission intensities of non-alternant PAHs, for the most part, are unaffected. Results of previous measurements show that nitromethane does quench the fluorescence emission of the nine acenaphthylene solutes studied, which is completly contrary to what would be expected based on the fact that all nine solutes are non-alternant PAHs. To investigate this phenomenon further, the fluorescence behaviour of 1-, 3-, 4-, 5-, 6-, 7-, 8-, 9- and 10- methylacephenanthrylene dissolved in neat acetonitrile, acetonitrile–ethyl acetate and acetonitrile–toluene solvents was measured at different nitromethane concentrations. Experimental results support the notion that the double bond in the five-membered ring is fixed; therefore, the solutes act as alternant rather than non-alternant PAHs.

Study of geometry effects on heavy atom perturbation of the electronic properties of derivatives of the nonalternant polycyclic aromatic hydrocarbons fluoranthene and acenaphtho[1,2-k]fluoranthene

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudy of geometry effects on heavy atom perturbation of the electronic properties of derivatives of the nonalternant polycyclic aromatic hydrocarbons fluoranthene and acenaphtho[1,2-k]fluorantheneBenjamin F. Plummer, L. Kraig Steffen, Tala L. Braley, W. Greg Reese, Kathryn Zych, Gregory Van Dyke, and Brock TulleyCite this: J. Am. Chem. Soc. 1993, 115, 24, 11542–11551Publication Date (Print):December 1, 1993Publication History Published online1 May 2002Published inissue 1 December 1993https://doi.org/10.1021/ja00077a061RIGHTS & PERMISSIONSArticle Views471Altmetric-Citations25LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

Spectroscopic Investigation of Fluorescence Quenching Agents. Part IV: Selectivity of Nitromethane for Discriminating between Alternant versus Nonalternant Polycyclic Aromatic Hydrocarbons in Solvents of Differing Polarities

To further assess the applicability of nitromethane as a selective quenching agent for alternant vs. nonalternant polycyclic aromatic hydrocarbons in HPLC analysis, we measured the effect that it has on the fluorescence emission behavior of 96 different polycyclic aromatic hydrocarbons dissolved in a binary ethyl acetate/acetonitrile solvent mixture. Nitromethane quenching results are compared with previously reported acetonitrile, aqueous/acetonitrile, and toluene/acetonitrile solvent mixtures. Results of these measurements revealed that the “selective quenching” rule is obeyed for the vast majority of PAHs in all solvents considered thus far, with the coronene derivatives being the only major exceptions.

Eine Anmerkung zum langwelligen UV-Übergang in alternierenden und dazu isomeren nichtalternierenden polycyclischen aromatischen Kohlenwasserstoffen

Abstract Based on the HMO formalism and for an infinite number of carbon centers an analytical solution for the ratio x = ∆ε(HOMO-LUMO)[NAH]/∆c(HOMO-LUMO)[AH] of nonalternant polycyclic aromatic hydrocarbons (NAH) and its respective counterparts (AH) is given. It is shown that generally x ≥ 1, which is in agreement with experimental observations.

Spectroscopic properties of polycyclic aromatic compounds: Part II. Fluorescence emission and quenching behavior of select acenaphthylene derivatives in organic nonelectrolyte solvents

Fluorescence emission spectra have been measured for acenaphthylene, aceanthrylene, acephenanthrylene, benz[ e]aceanthrylene, 3-methylbenz[ j]aceanthrylene, 6-methylbenz[ j]aceanthrylene, benzo[ def]cyclopenta[ hi]chrysene, cyclopenta[ cd]pyrene (also called acepyrylene) and acenaphth[1,2 a]acenaphthylene in organic nonelectrolyte solvents of varying polarity. Benz[ e]aceanthrylene was found to exhibit probe character for many of the solvents considered; however, emission intensity ratios in benzene, toluene, p-xylene and o-xylene were too small compared against nonelectrolyte solvents of similar polarity. The effect of nitromethane as selective quenching agent was also examined. Results of these measurements show that nitromethane does quench the fluorescence emission of the nine solutes studied, which is contrary to what would be expected based upon the fact that all nine solutes are nonalternant polycyclic aromatic hydrocarbons.

Spectroscopic Investigation of Fluorescence Quenching Agents. Part III: Effect of Solvent Polarity on the Selectivity of Nitromethane for Discriminating between Alternant versus Nonalternant Polycyclic Aromatic Hydrocarbons

To better assess the applicability of nitromethane as a selective quenching agent for alternant versus nonalternant polycyclic aromatic hydrocarbons in HPLC, TLC, and HPTLC analysis, we measured the effect that it has on the fluorescence emission behavior of 96 different polycyclic aromatic hydrocarbons dissolved in binary toluene/acetonitrile solvent mixtures. Results of these measurements revealed that the “selective quenching” rule is obeyed for the vast majority of PAHs, with the coronene derivatives being the only major exceptions. Fluorescence emission spectra are also reported for benzo[g]chrysene, naphtho[2,3g]chrysene, 4 H-benzo[c]cyclopenta[mno]chrysene, dibenzo[ghi,mno]fluoranthene (commonly called corannulene), rubicene, diacenaphtho[l,2j:l‘,2'l]fluoranthene, 10-methyl-benzo[b]fluoranthene, 3-methoxybenzo[k]fluoranthene, and 3-hydroxybenzo[k]fluoranthene in organic nonelectrolyte solvents of varying polarity. Calculated emission intensity ratios failed to vary systematically with solvent polarity, and all nine of the aforementioned solutes were thus classified as nonprobe molecules.

Preparation and Spectroscopic Characterization of Cyclopenta[1,2-a : 3,4,5-b′c′]dicoronene

The non-alternant hydrocarbon cyclopenta[1,2-a : 3,4,5-b′c′]dicoronene (3) has been prepared by aluminium chloride catalyzed dimerization of coronene (1). The UV/VIS absorption spectrum, fluorescence spectrum and fluorescence quantum yield of 3 is reported and compared with that of the alternant isomer benzo[1,2,3-bc:4,5,6-b′c′]dicoronene (2). Relationships observed in the UV/VIS absorption spectra of alternant and non-alternant polycyclic aromatic hydrocarbons and preliminary theoretical investigations (PMO calculations) on two model systems (C, E) are also reported.

Fluorine probes for investigating the mechanism of activation of indeno [1,2,3-cd]pyrene to a tumorigenic agent

Indeno[1,2,3-cd]pyrene (IP) is a non-alternant polycyclic aromatic hydrocarbon that has tumor-initiating activity on mouse skin and is carcinogenic in newborn mice and in rat lungs. Previous studies have shown that 8- and 9-hydroxyIP and IP-1,2-diol are major metabolites formed in vivo in mouse skin. 8-HydroxyIP-1,2-diol and 9-hydroxyIP-1,2-diol are also observed as in vivo metabolites of IP. Although 8-hydroxyIP had marginal tumor-initiating activity on mouse skin, IP-1,2-diol and its epoxide precursor, IP-1,2-oxide, had similar tumorigenic activity as IP. In the present study fluorine probes have been employed to investigate the contribution of metabolic activation at the 1,2 and 7-10 positions of IP. At a total initiating dose of 4.0 mumol, 2-fluoroIP induced skin tumors in 76% of the treated animals with an average of 3.9 tumors/mouse. At the same dose, IP induced a 72% incidence of tumor-bearing mice with 2.1 tumors/mouse. In contrast, 8,9-difluoroIP elicited a tumorigenic response in 40% of the treated animals with 0.6 tumors/animal. Five mice from each experimental group were killed at the conclusion of the initiation phase of the bioassay and DNA was isolated from the treated areas of skin. 32P-Postlabeling analysis of the hydrolyzed DNA indicated that IP forms one major detectable DNA adduct that migrates close to the origin. This adduct is absent in mice treated with 8,9-difluoroIP. In contrast, 2-fluoroIP forms one major adduct spot with different retention behavior as compared with the adduct formed from IP. DNA from mice treated topically with IP-1,2-diol and IP-1,2-oxide was subjected to 32P-postlabeling analysis. IP-1,2-diol forms one major DNA adduct spot with mobility similar to that observed for the IP-DNA adduct. IP-1,2-oxide displayed an intense pattern of DNA adducts centered around the location of the IP-DNA adduct. No adducts were detected which had mobility similar to that formed from 2-fluoroIP. These results are consistent with IP undergoing metabolic activation at positions 7-10 either alone or in conjunction with dihydrodiol formation at the 1,2 position.

Tumorigenic activity of non-alternant polynuclear aromatic hydrocarbons in newborn mice

The tumorigenic activity of benzo[ b]fluoranthene, benzo[ j]fluoranthene, benzo[ k]fluoranthene, and indeno-[1,2,3- cd]pyrene was evaluated in newborn CD-1 mice. The total doses of these non-alternant polycyclic aromatic hydrocarbons employed in this study ranged from 0.5 to 2.1 μmol per mouse. The results of this assay indicate that both benzo[ b]fluoranthene and benzo[ j]fluoranthene exhibit significant tumorigenic activity. In contrast to these results, neither benzo[ k]fluoranthene nor indeno[1,2,3- cd]pyrene were tumorigenic under these assay conditions.

MO theory of ease of formation of carbocations derived from nonalternant polycyclic aromatic hydrocarbons

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMO theory of ease of formation of carbocations derived from nonalternant polycyclic aromatic hydrocarbonsJohn P. Lowe and B. D. SilvermanCite this: J. Am. Chem. Soc. 1984, 106, 20, 5955–5958Publication Date (Print):October 1, 1984Publication History Published online1 May 2002Published inissue 1 October 1984https://doi.org/10.1021/ja00332a033RIGHTS & PERMISSIONSArticle Views68Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (494 KB) Get e-Alerts Get e-Alerts

Metal carbonyl complexes of 3,5-dimethylaceheptylene. Synthesis and molecular structures of (C14H8Me2)Mn2(CO)6 and (C14H8Me2)Fe3(CO)8

The reactions of the non-alternant polycyclic aromatic hydrocarbon 3,5-dimethylaceheptylene, C14H8Me2, with various transition metal carbonyls and the molecular geometry of the compounds (C14H8Me2)Mn2(CO)6 and (C14H8Me2)Fe3(CO)8 is shown.

Application of the molecular orbital ω-technique to aromatic substitution

The ω-technique of the simple MO method is found to provide a reasonably good correlation with the available experimental data on partial rate factors of nitration of alternant and non-alternant polycyclic aromatic hydrocarbons.