First identification of benzo[ghi]naphtho[8,1,2-bcd]perylene as a product of fuel pyrolysis, using high-performance liquid chromatography with diode-array ultraviolet-visible absorbance detection and mass spectrometry

We present HPLC/UV/MS evidence to support the identification of benzo[ghi]naphtho[8,1,2-bcd]perylene as a product of supercritical toluene pyrolysis. Mass spectral data confirm that compound I-eluting in between co-eluting benzo[a]coronene/phenanthro[5,4,3,2-efghi]perylene and benzo[pqr]naphtho[8,1,2-bcd]perylene, all three of which have been unequivocally identified as C(28)H(14) products of toluene pyrolysis-is also a C(28)H(14) product component. The UV spectrum of compound I is presented, and indicates that it is a benzenoid polycyclic aromatic hydrocarbon (PAH). Five of the eight benzenoid C(28)H(14) PAH isomers have published UV spectra, and characteristics of the remaining three are deduced from annelation theory. Only one of these compounds, benzo[ghi]naphtho[8,1,2-bcd]perylene, is predicted to have a UV spectrum with characteristics that we find in the spectrum of compound I. In addition, benzo[ghi]naphtho[8,1,2-bcd]perylene is the only benzenoid C(28)H(14) isomer whose length-to-breadth ratio is consistent with the HPLC retention time of compound I. The reaction mechanism through which benzo[ghi]naphtho[8,1,2-bcd]perylene is formed in this environment is shown, and is consistent with reaction pathways of other large PAH found in this product mixture.     

Polycyclic aromatic hydrocarbon solute probes. Part II. Effect of solvent polarity on the fluorescence emission fine structures of coronene derivatives

The fluorescence properties of coronene (Co), benzo[a]coronene (BCo), naphtho[2,3-a]coronene (NCo), dibenzo[a,j]coronene (DCo), naphtho[1,2,3,4-ghi]perylene, benzo[pqr]naphtho[8,1,2-bcd]perylene and dibenzo[cd,lm]perylene dissolved in solvents of varying polarity are reported. Measurements indicated that the emission intensities of the four coronene derivatives depended on solvent polarity. The Co, BCo and NCo scales have been defined as the ratio of the fluorescence intensities of bands I and III of the vibronic spectra. Band III of dibenzo[a,j]coronene was not clearly identifiable in all the solvents studied, and the DCo scale was therefore defined as the intensity ratio of band I and IV. Emission intensity ratios of the three perylene derivatives remained nearly constant, irrespective of solvent polarity.     

First identification of benzo[cd]phenanthro[1,2,3-lm]perylene by high-pressure liquid chromatography with ultraviolet-visible spectroscopy and mass spectrometry

Benzo[cd]phenanthro[1,2,3-lm]perylene has been identified as a product of supercritical 1-methylnaphthalene pyrolysis from an experiment performed at 585 °C, 110 atm, and 140 s in a supercritical fluid flow reactor. The identification of benzo[cd]phenanthro[1,2,3-lm]perylene is based on the product's mass spectrum, HPLC elution time, and UV absorbance spectrum. The mass spectrum of the identified 1-methylnaphthalene pyrolysis product, called component I here, reveals a molecular weight of 426, corresponding to a C₃₄H₁₈ polycyclic aromatic hydrocarbon (PAH). The extremely long HPLC elution time, 20–48 min longer than those of the four other C₃₄H₁₈ PAH components in this product mixture, indicates that component I has a planar structure with a high length-to-breadth ratio. Annellation theory is used to interpret and compare the UV spectrum of component I with those of the C₃₀H₁₆ benzo[cd]naphtho[1,2,3-lm]perylene and the C₃₆H₁₈ teropyrene, structures with one ring less and one ring more, respectively, than that of component I. This analysis of component I's UV spectrum, in conjunction with its mass spectrum and HPLC elution behavior, all lead to the identification of component I as the nine-ring PAH benzo[cd]phenanthro[1,2,3-lm] perylene, a molecule whose existence has never before been documented.     

Effect of column temperature on the retention of peropyrene-type polycyclic aromatic hydrocarbons on various chemically bonded stationary phases in reversed-phase liquid chromatography

The effect of column temperature on the reversed-phase retention of polycyclic aromatic hydrocarbons has been investigated using various chemically bonded phases. Four solutes, coronene, tetrabenzo[a,cd,j,lm]perylene, tetrabenzo[a,cd,f,lm]perylene and benzo[lm]phenanthro[4,5,6-abcd]perylene, were used as the test probes. The temperature dependences of the retention are almost linear (the logarithm of capacity factor is proportional to the reciprocal of the column absolute temperature) with monomeric C18, monomeric C18 with endcapping and diphenyl bonded phases, while non-linear behaviour was observed with polymeric C18 phases. These differences in behaviour of the stationary phases are interpreted in terms of their structural differences.     

Overcrowding motifs in large PAHs. An ab initio study.

Planar and overcrowded LPAHs C(34)H(18) anthra[9,1,2-cde]benzo[rst]penaphene (1), benzo[rst]phenanthro[10,1,2-cde]pentaphene (2), tetrabenzo[a,cd,j,lm]perylene (3), tetrabenzo[a,cd,lm,o]perylene (4), and LPAHs C(38)H(18) anthra[2,1,9,8-klmno]naphtho[3,2,1,8,7-vwxyz]hexaphene (5), dianthra[2,1,9,8-stuva;2',1',9',8'-hijkl]pentacene (6), dibenzo[jk,uv]dinaphtho[2,1,8,7-defg;2',1',8',7'-opqr]perylene (7), diphenanthro[5,4,3-abcd;3',4',5'-lmno]perylene (8), potential products of peri-peri reductive couplings of benzanthrone and of naphthanthrone, respectively, were subjected to an ab initio study with emphasis on overcrowding motifs. The HF and DFT B3LYP methods were employed to calculate energies and geometries of the minima conformations of these LPAHs. The most stable LPAHs in these series were found to be planar C(2)(v)()-1 and C(2)(v)()-5, respectively. Among overcrowded LPAHs, twisted-folded C(2)-3 and C(2)-7 with two cove regions were found to be more stable than their respective isomers twisted-folded C(2)-4 and C(2)-8 with one fjord region each, in contrast to the semiempirical predictions. The energy differences between the most stable planar isomer and the overcrowded isomers were significantly smaller in the C(38)H(18) series, than in the C(34)H(18) series. Overcrowded twisted-folded C(2)-7 with two coves was found to be more stable than planar C(2)(h)()-6 by 2.0 kJ/mol (at B3LYP/6-311G), indicating enhanced role of aromatic stabilization and decreased destabilization due to overcrowding, with increasing the number of aromatic rings. Heats of formation of LPAHs 1-8 were derived from the ab initio total energies (at B3LYP/6-31G). A search of the conformational spaces of 3 and 4 revealed an anti-folded local minimum C(i)()-3 and a syn-folded transition state C(s)()-4, 23.7 and 120.3 kJ/mol higher in energy than the twisted-folded C(2)-3 and C(2)-4, respectively (at B3LYP/6-31G). The cove and fjord torsion angles in the C(38)H(18) series were found to be smaller than in the C(34)H(18) series. The nonbonding distances between carbon atoms at cove and fjord regions of the overcrowded LPAHs were found to be smaller than the sum of the van der Waals radii of two carbon atoms     

Effect of overcrowding in mass spectra for six violanthrenes

The mass spectra of six highly purified violanthrene samples of class A—(benzo[rst]anthro[10,1,2-cde]pentaphen, benzo[rst]phenanthro[10,1,2-cde]pentaphene), class B—(benzo[rst]phenanthro[1,10,9-cde]pentaphene, dibenzo[a,rst]naphtho[8,1,2-cde]pentaphene) and class T—(tetrabenzo[a,cd,j,lm]perylene, tetrabenzo[de,hi,op,st]pentacene) were measured. The dependence of relative ion instensities for monovalent, divalent and trivalent ions [M]ⁱ⁺, [M – 2n]ⁱ⁺ and [M – 15]ⁱ⁺ (i = 1, 2, 3) showed clearly the effect of overcrowding in condensed aromatic rings, i.e. the number of H₂ molecules which are readily eliminated from the molecular ions is zero for class A, one for class B, and two for class T. These numbers are the same as the number of overcrowded hydrogen atom pairs for each class.     

Urceolatin, a structurally unique bromophenol from Polysiphonia urceolata

6-Bromo-1-(3-bromo-4,5-dihydroxybenzyl)phenanthro[4,5-bcd]furan-2,3,5-triol (urceolatin, 1), a highly oxygenated bromophenol containing an unprecedented naturally occurring benzylphenanthro[4,5-bcd]furan unit, was isolated from the marine red alga Polysiphonia urceolata. Its structure was established on the basis of extensive spectroscopic analysis. Compound 1 displayed significant DPPH radical-scavenging activity with an IC50 value of 7.9 microM, which is 10-fold more potent than that of the positive control, butylated hydroxytoluene.     

Identification of naphtho [8.1.2 abc] coronene in the extract of diesel particulate matter by non-aqueous reversed-phase liquid chromatography coupled with UV multichannel detector

Summary Non-aqueous reversed-phase liquid chromatography coupled with a UV multichannel detector has been used for the identification of large polycyclic aromatic hydrocarbons in the extract from diesel engine particulate matter. The existence of naphtho[8,1,2,abc]coronene is first confirmed by this technique.     

Determination of organic sulphur compounds in sediments of the river Elbe using gas chromatography with flame photometric detection

Sediment samples from different reference sites representing typical situations on the river Elbe were analyzed for organo-sulphur compounds (OSC). Gas chromatography with sulphur specific flame-photometric detection was used for the identification and quantification of individual OSC. Chromatographic retention data for 42 standard heterocycles were determined and compared with the composition of sediment extracts. An extraction scheme used for the OSC determination is described. Dibenzothiophene (DBT), its alkylated homologues, phenanthro[4,5-bcd]thiophene, benzo[b]naphtho[2,1-d]thiophene and in some cases still unidentified compounds were the predominant OSC. Depending on sampling site and date the qualitative composition of sulphur heterocycles detected by the described method varied, and the total concentrations of all OSC ranged from 0.3 to 21 mg/kg.     

Determination of Polycyclic Aromatic Hydrocarbons in Airborne Particulate by High Performance Liquid Chromatography

This paper presents a trisolvent ultrasonic extraction and HPLC analysis method for the determination of 11 polycyclic aromatic hydrocarbons in air particulate collected on an air filter by a commercial high volume air sampler. A reverse phase column, Vydac 201 TP, and a gradient mobile phase, acetonitrile/water, were used. The 11 PAHs, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a, h]anthracene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and coronene were completely resolved under experimental conditions. All the PAHs except coronene were monitored by fluorescence with λ_ex=270 nm, λ_em>389 nm. Coronene was monitored by UV with λ=300 nm. The methodology was evaluated by spiking SRM 1649 with a PAH standard and then going through different extraction procedures and analyzing the PAH concentrations without clean-up. An external standard method was used for quantitation. The recovery yields for fluoranthene, benz[a]anthracene, benzo[a]pyrene, benzo[ghi]perylene and indeno[l,2,3-cd]pyrene were above 90%. The detection limits of PAH with fluorescence at λ_ex=270 nm, λ_em>389 nm ranged from 5.7 pg to 69.5 pg.     

Donor-acceptor copolymers from cyclopentannulation polymerizations with dicyclopenta[cd,jk]pyrene and dicyclopenta[cd,lm] perylene acceptors

A series of donor-acceptor copolymers with dicyclopenta[cd,jk]pyrene and dicyclopenta[cd,lm]perylene acceptor units was prepared via palladium catalyzed cyclopenta-annulation reactions. The acceptor units were paired with diethynyl containing donor groups based on benzo[1,2-b:4,5-b’]dithiophene, thieno[3,2-b]thiophene, and 4-octyl-4H-dithieno[3,2-b:2′,3′-d]pyrrole to create six polymer variants. The cyclopentannulation polymerization resulted in copolymers with molecular weights (Mn) of 6–14 kDa and broad light absorption in the visible region with band gaps of 1.38–1.85 eV. The synthetic methodology, as well as optoelectronic properties, including thin-film absorption and cyclic voltammetry, of the donor-acceptor copolymers are presented.     

Determination of polycyclic aromatic hydrocarbons, azaarenes, and thiaarenes emitted from coal-fired residential furnaces by gas chromatography/mass spectrometry

Summary Since the carcinogenic effect of emissions from hard coal briquet-fired furnaces is almost entirely caused by polycyclic aromatic compounds (PAC) with more than three rings, the composition of this fraction has been analyzed in detail.More than 170 neutral [111 polycyclic aromatic hydrocarbons (PAH), 57 thiaarenes, 6 oxaarenes] and 70 basic (azaarenes) compounds were characterized as PAC by means of GC/MS (limit of detection 0.1 mg/kg briquet). About 80 compounds were identified by comparison with reference standards. In order to obtain unequivocal evidence for the identification of 11 PAH with a molecular weight of 302, the UV- and fluorescence spectra were compared with those of the synthesized reference compounds [naphtho(1,2-k) fluoranthene, dibenz(e,k)acephenanthrylene, naphth-(2,3e) acephenanthrylene, naphtho(2,3-k)fluoranthene, dibenzo (de,qr)naphthacene, coronene, dibenzo(fg,op)naphthacene, naphtho(1,2,3,4-def)chrysene, benzo(b)perylene, dibenzo (-def,j)chrysene, benzo(rst)pentaphene]. In case of the emission condensate from hard coal briquets, PAC containing 6 and more rings cause about 50% of the carcinogenic effect in animal experiments.

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Bestimmung von polycyclischen aromatischen Kohlenwasserstoffen, Azaarenen und Thiaarenen in der Emission von Kohle-beheizten Haushaltöfen — Bestandsaufnahme durch GC/MS

Zusammenfassung Da die krebserzeugende Wirkung von Emissionen aus Steinkohlebrikett-beheizten Zimmeröfen nahezu vollständig durch die im Kondensat enthaltenene polycyclischen aromatischen Verbindungen (PAC) mit mehr als 3 Ringen verursacht wird, wurde die Zusammensetzung dieser PAC-Fraktion untersucht.Mehr als 170 neutrale [111 polycyclische aromatische Kohlenwasserstoffe (PAH), 57 Thiaarene, 6 Oxaarene] sowie 70 basische Verbindungen (Azaarene) konnten mit der GC/MS-Kombination als PAC charakterisiert werden (Nachweisgrenze 0,1 mg/kg Brikett). Etwa 80 Verbindungen wurden durch den Vergleich mit Referenzsubstanzen identifiziert. Um in einigen zweifelhaften Fällen die Identität der isolierten mit der synthetischen Verbindung zu bestätigen, wurden bei 11 PAH mit einem Molgewicht von 302 zusätzlich auch UV- und Fluorescenzspektren verglichen [Naphtho(1,2-k)fluoranthen, Dibenz(e,k)acephenanthrylen, Naphth(2,3-e)acephenanthrylen, Naphtho(2,3-k)fluoranthen, Dibenzo(de,qr)naphthacen, Coronen, Dibenzo(fg,op)naphthacen, Naphtho(1,2,3,4-def)chrysen, Benzo(b)perylen, Dibenzo(def,j)chrysen, Benzo(rst)pentaphen]. Diese Verbindungen sind von besonderem Interesse, da PAC mit 6 und mehr Ringen im Tierversuch etwa 50% der carcinogenen Wirkung des Steinkohlenbrikett-Emissionskondensates verursachen.

     

Comparing the stability of tribenzo[ b , n , pqr ]perylene and tribenzo[ b , k , pqr ]perylene

Two isomeric benzenoid hydrocarbons – tribenzo[b,n,pqr]perylene and tribenzo[b,k,pqr]perylene played a crucial role in the formulation of the Clar aromatic sextet theory. The basic assumption of this theory is that tribenzo[b,n,pqr]perylene is more stable than tribenzo[b,k,pqr]perylene because the former has five, whereas the latter only four aromatic sextets. We now approach this stability problem from a different direction. By means of a recently developed molecular-orbital-based method it is possible to estimate the energy effects of individual cycles, as well as pairs, triplets, etc. of cycles in polycyclic conjugated molecules. From these energy-effects one can better understand which structural details are responsible for the thermodynamic stability of the underlying molecule. In particular, it is possible to rationalize (in a quantitative manner) the causes of differences in the thermodynamic stability of isomers. Our analysis corroborates the conclusion of Clar theory, but points out a number of hitherto overlooked structure-stability connections.     

Comparing the stability of tribenzo[ b , n , pqr ]perylene and tribenzo[ b , k , pqr ]perylene

Two isomeric benzenoid hydrocarbons – tribenzo[b,n,pqr]perylene and tribenzo[b,k,pqr]perylene played a crucial role in the formulation of the Clar aromatic sextet theory. The basic assumption of this theory is that tribenzo[b,n,pqr]perylene is more stable than tribenzo[b,k,pqr]perylene because the former has five, whereas the latter only four aromatic sextets. We now approach this stability problem from a different direction. By means of a recently developed molecular-orbital-based method it is possible to estimate the energy effects of individual cycles, as well as pairs, triplets, etc. of cycles in polycyclic conjugated molecules. From these energy-effects one can better understand which structural details are responsible for the thermodynamic stability of the underlying molecule. In particular, it is possible to rationalize (in a quantitative manner) the causes of differences in the thermodynamic stability of isomers. Our analysis corroborates the conclusion of Clar theory, but points out a number of hitherto overlooked structure-stability connections. Correspondence: Ivan Gutman, Faculty of Science, University of Kragujevac, P.O. Box 60, 34000 Kragujevac, Serbia.     

Toward a visible light mediated photocyclization: Cu-based sensitizers for the synthesis of [5]helicene

A photochemical synthesis of [5]helicene employing a copper-based sensitizer 7 has been developed that avoids the disadvantages associated with the traditional UV light mediated method. The visible light mediated synthesis uses common glassware and a simple household light bulb without the competing formation of [2 + 2] cycloadducts, regioisomers, or the overoxidation product benzo[ghi]perylene 3. Preliminary results show that the reaction time can be significantly reduced through the use of a continuous flow strategy.     

Infrared spectroscopy of matrix-isolated polycyclic aromatic hydrocarbon cations. 2. The members of the thermodynamically most favorable series through coronene

Gaseous, ionized polycyclic aromatic hydrocarbons (PAHs) are thought to be responsible for a very common family of interstellar infrared emission bands. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene:phenanthrene, pyrene, benzo[e]pyrene, benzo[ghi]perylene, and coronene, are presented to test this hypothesis. For those molecules that have been studied previously (pyrene, pyrene-d10, and coronene), band positions and relative intensities are in agreement. In all of these cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeuteriophenanthrene, pyrene, benzo[ghi]perylene, and coronene cations. With the exception of coronene, the cation bands corresponding to the CC modes are typically 2-5 times more intense than those of the CH out-of-plane bending vibrations. For the cations, the CC stretching and CH in-plane bending modes give rise to bands that are an order of magnitude stronger than those of the neutral species, and the CH out-of-plane bends produce bands that are 5-20 times weaker than those of the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.     

The electronic spectrometry of two similar tetrabenzoperylene isomers

The u.v. absorbance and fluorescence excitation spectra of two large polycyclic aromatic hydrocarbons (PAHS) are compared. Tetrabenzo[a,cd,j, lm]perylene, the previously known isomer, behaves as expected, while the new isomer, tetrabenzo[a,cd,f,lm]perylene, has a u.v. absorbance spectrum which is very different from its fluorescence excitation spectrum. This is the only known PAH in which this behavior has been found.     

A Novel Spiro[acridine‐9,9′‐fluorene] Derivatives Containing Phenanthroimidazole Moiety for Deep‐Blue OLED Application

Typical π–π stacking and aggregation‐caused quenching could be suppressed in the film‐state by the spiro conformation molecular design in the field of organic light‐emitting diodes (OLEDs). Herein, a novel deep‐blue fluorescent material with spiro conformation, 1‐(4‐(tert ‐butyl)phenyl)‐2‐(4‐(10‐phenyl‐10H ‐spiro[acridine‐9,9′‐fluoren]‐2‐yl)phenyl)‐1H ‐phenanthro[9,10‐d ]imidazole ( SAF‐BPI ), was designed and synthesized. The compound consists of spiro‐acridine‐fluorene (SAF) as donor part and phenanthroimidazole (BPI) as acceptor part. Owing to the rigid SAF skeleton, this compound exhibits a high thermal stability with a glass transition temperature (T _g) of 198 °C. The compound exhibits bipolar transporting characteristics demonstrated by the single‐carrier devices. The non‐doped OLEDs based on the SAF‐BPI as the emitting layer shows maximum emission at 448 nm, maximum luminance of 2122 cd m⁻², maximum current efficiency (CE) of 3.97 cd A⁻¹, and a maximum power efficiency of 2.08 lm W⁻¹. The chromaticity coordinate is stable at (0.15, 0.10) at the voltage of 7–11 V. The device shows a slow efficiency roll‐off with CE of 3.35 and 2.85 cd A⁻¹ at 100 and 1000 cd m⁻², respectively.     

A quaternary solvent system for the reverse-phase liquid-chromatographic separation of polycyclic aromatics

Modern liquid chromatographic (LC) conditions which effect a separation of polycyclic aromatic hydrocarbons (PAH) containing up to ten rings are described. The LC conditions include reverse-phase chromatographic columns in combination with a quaternary solvent system. Methanol and water are combined to form solvent system A, while tetrahydrofuran and acetonitrile form solvent system B. Solvent systems A and B are then combined in a linear gradient relationship to effect the separation. The separation of benzo(a)pyrene and perylene along with benzo(ghi)perylene and indeno (1,2,3-cd)pyrene is achieved. In the same chromatogram the PAHs, coronene, dibenzo(a,e), (a,i), (a,h)pyrene and tribenzo(a,e,i)pyrene are also separated. An increase in column temperature from 45°C to 55°C is shown to shorten the elution time and increase chromatographic resolution of many of the PAHs examined. At least 25 PAHs ranging in molecular weight from 178 to 536 are examined for their chromatographic behavior. As examples, the application of this method to samples from a coal liquefication process are included. The samples are examined with both a UV detector and fluouescence detector to demonstrate the utility of dual detectors when analyzing for PAHs in complex matrices. With minor modification of the gradient this method is applicable to PAHs containing ring systems other than those reported here.     

焦炉降尘中多环芳烃的毛细管超临界流体色谱分析

研究了９个多环芳烃混合样品的超临界流体色谱分析条件，并与毛细管气相色谱法做了比较。超临界流体色谱的条件是：柱温１１０℃；程序升压９．０ＭＰａ（５ｍｉｎ）１．４ＭＰａ／ｍｉｎ２８．０ ＭＰａ。各组分保留时间的相对标准偏差为 １．４％～３．０％，定量分析的相对误差为１．４％～６．０％，比毛细管气相色谱法具有明显的优越性。试验了焦炉降尘样品，发现该样品主要由双环和三环的多环芳烃类物质组成。其中萘含量约占８０％。