Dibenzo chrysene, from

Fig. 10 Composition and spatial distribution of the main patterns of contamination identified in sediment of the Ebro River basin from year 2004 to 2006. Different temporal distribution of the PAHs pattern of contamination over the territory and constant distribution in time of the APs and heavier PAHs as well as the OCs pattern. Big circles representing higher levels of pattern contribution than small circles. Variables identification 1, naphthalene 2, acenaphtylene 3, acenapthene 4, fluorene 5, phenanthrene 6, anthracene 7, fluoranthene 8, pyrene 9, benzo(a) anthracene 10, chrysene 11, benzo(b)fluoranthene 12, benzo(k)fluoranthene 13, benzo(a)pyr-ene 14, indeno(l,2,3-cd)pyrene 15, dibenzo(a,h)anthracene 16, benzo(g,h,i)perylene 17, octyl-phenol 18, nonylphenol 19, tributylphosphate 20, a-HCH 21, HCB 22,2,4-DDE 23,4,4-DDE 24, 2,4-DDD 25, 4,4-DDD 26, 2,4-DDT 27, 4,4-DDT...

Fig. 11 Composition of the identified patterns of contamination (loadings) in sediment and soil of the Ebro River basin and patterns contribution to the analyzed samples (scores) in fall from year 2004 to 2006. Samples ordered for both compartments from first to third sampling campaigns and, for each campaign, from NW to SE. Variables identification 1, acenaphtylene 2, phenanthrene 3, anthracene 4, fluoranthene 5, pyrene 6, benzo(a)anthracene 7, chrysene 8, benzo(b)fluor-anthene 9, benzo(k)fluoranthene 10, benzo(a)pyrene 11, indeno(l,2,3-cd)pyrene 12, dibenzo (a.h)anthracene 13, benzo(g,h,i)perylene 14, tributylphosphate 15, 4,4-DDE...

The siimples were analysed by fluorescence spectroscopy at the conditions for each specific PAH [5] previously determined with the model compounds. The PAH studied are those listed by the US Environmental Protection Agency as priority pollutants [6] Fluorene, Benzo(a)Pyrene, Pyrene, Chrysene, Anthracene, Acenaphthene, Bezo(a)Anthracene, Dibenzo(a,h)Anthracene, Coronene, Perylene and Benzo(k)fluoranthene. In addition, Coronene emissions were also reported due to their important role on PAH stabilization at extreme conditions [7]. These 16 PAH were analysed from all runs in each of the four samples. 

Fig. 1 Gas chromatography-flame ionization detection chromatogram of a complex mixture of PAHs extracted by SFE from a contaminated soil. (1) naphthalene (2) 2-methylnaphthalene (3) 1-methylnaphthalene (4) acenaphthene (5) fluorene (6) dibenzothiophene (7) phenanthrene (8) anthracene (9) fluoranthene (10) pyrene (11) benzo(a)anthracene (12) chrysene (13) benzo(e)pyrene (14) benzo(a)pyrene (15) indeno(l,2,3-cd)pyrene (16) dibenzo(a,h)anthracene (17) benzo(g,h,i)perylene. (From Ref. [12].)...

The dependence of NMR patterns upon states of solvation should not be overlooked. This aspect of polyanion chemistry has been discussed (Sect. 4). The influence of the counter cation upon the dianion though unaccounted for by simple calculations is supposed to vary from system to system. The different topologies of the anions and different modes of delocalization may be responsible for the deviations from a linear dependence of the correlation. From Table 9 one can arrive at conclusions on the relative antiaromaticity of the various anions. For example, benzanthracene dianion 49 ) is less antiaromatic than chrysene dianion (542 ), and dibenzo-anthracene dianion (J/2-) is more antiaromatic than the pentacene dianion (472 ). It is also proposed that H NMR paratropic shifts may be used to calibrate the LUMO-HOMO energy gap. 

Treatment of ketone 409 with lithium diisopropylamide (LDA) results in the ethyl 1,2-dihydroxybenzoate 410 in a 74% yield (equation 191) . The acid-catalyzed isomerization of diarene oxides derived from benz[a]anthracene, chrysene and benzo[c]phenanthrene gives mixtures of isomeric polycyclic phenols. Finally, it should be mentioned that dibenzo[i>, ]oxepin 411 undergoes an interesting rearrangement to 2-hydroxyphenylindene 412 (equation 192). 

Lee and White developed excellent data on polycyclic aromatic hydrocarbons, from naphthalene up to dibenzo[Jc/,w o]chrysene. " The single index yielded a QSAR with a standard deviation 5 = 5.8. The following three-variable equation gives an improved relation ... 

Although B[fl]P was reported as a CSC component in the mid-1950s by several American (55-57, 592-594) and British investigators (820) on the basis of spectral evidence, Fieser, as late as 1957 (1181), considered the published evidence to be inadequate as proof of the presence of B[a]P in CSC. Obviously, in 1957 Fieser was unaware of the report by Rodgman in 1956 (3240) on the isolation of crystalline B[a] P from MSS or the reports by Falk and Kotin in 1955 and 1956 (1172) on the determination of the per cigarette yields of B[fl]P (plus B[fl]A and dibenzo[sidestream smoke (SSS). Shortly thereafter, in 1959, Wynder and Hoffmann reported the isolation of B[fl]P in crystalline form from CSC (4307), thus ending the controversy about its presence in cigarette smoke. 

Severalcarcinogenichigheraromaticpolycyclichydrocarbons [are] present in tobacco smoke condensate. They include benzo[a]pyrene. .., benzo[e]pyrene. .., chrysene. .., benz[a] anthracene. .., dibenz[a,/i]anthracene. .., and dibenzo[a,i] pyrene. .. From the amount in which these materials have been found in tobacco smoke condensate it was evident that these, by themselves, could not account for the total biological activity observed. 

Table XXV-6, adapted from Lam (2257), demonstrates the relationship between PAH generation and pyrolysis temperature for aliphatic tobacco hydrocarbons pyrolyzed in air at several temperatures. Calculation of the yield ratios [PAH, mg/g B[a]P, mg/g] of the other PAHs vs. B[a]P reveals significant information In this case of pyrolysis, there was no consistency between the change in ratios of PAH/B[a]P as the temperature was increased from 700°C to 800°C, for example, in the case of the tetracyclic PAHs, the PAH/B[a]P ratio decreased for pyrene and chrysene but increased for fluoranthene for the pentacyclic PAHs, the ratio decreased for both perylene and B[c]P for the hexacyclic PAH dibenzo[t/c/mno]chrysene, the ratio increased. These same trends existed whether PAH/B[a]...

Dibenzo[a,/]pyrene (dibenzo[<7 /p]chrysene) is present in CSC and the pyrolysate from saturated tobacco hydrocarbons [Wynder et al. (4355)]. It was identified on the basis of agreement between spectral data for the isolate and those published for a synthetic PAH [Lyons and Johnston (2430), Lyons (2427, 2428), Wynder and Wright (4354), Rodgman and Cook (3273), Pyriki (3033), Bonnet and Neukomm (398, 399)]. 

Lavit-Lamy and Buu-Hor (2314) demonstrated that the synthetic PAH originally defined as dibenzo[q,/]pyrene (dibenzo[r/e/p]chrysene) and spectrally identical with the tobacco smoke isolate was actually dibenz[q,e]aceanthrylene (dibenzo[q,e] fluoranthene), a fact accepted by Hoffmann and Wynder (1798). Dihenza[def,p chrysene (dibenzo[a,/]pyrene) was subsequently identified in tobacco smoke by Snook et al. (3756), but no quantitative data were reported. In citations of dibenzo[a,Z]pyrene as a tumorigenic agents in tobacco smoke, Hoffmann and his coauthors (1727,1740, 1741, 1743,1744, 1773), lARC (1869,1870), and ERA (1148) indicated only that it was present. Whether its presence was based on the erroneous dibenzo[a,/]pyrene reports from the 1950s or the authentic dibenzo[a,Z]pyrene report of Snook et al. (3756) is unclear. 

In a similar effort, the BN for C C isosteric replacement niitnic 95 of dibenzo, p]chrysene was prepared in several steps from bis(biphenyl-2-yl) amine and its X-ray crystal structure determined for a direct comparison with that of the parent PAHs (Scheme 30) (201 IJAl8614). A condition-variation study of the last step revealed that 4 equivalents of Lewis acid AICI3 and 1.5 equivalents of the additive 2,2,6,6-tetramethylpiperidine... 

As experimental support for his model, Clar considered regularity in shifts of certain bands toward the violet and beyond in the UV spectra of structurally related benzenoids. As one moves from green linear hexacene toward colorless, the most branched dibenzo[g,p]chrysene (Figure 11.5), the shifts reflect the increasing stability of these benzenoids. Moving from linear hexacene to dibenzochrysene also parallels the increase in the number of aromatic sextets in these compounds. 

FIGURE 11.5 Shift of UV and visible spectral peaks as the number of aromatic sextets increases from hexacene to dibenzo[g,p]chrysene. 

Data from southern England document the rising burden for soil by PAHs, arguably due to anthropogenic activities. The PAHs content in the surface soil layer (30 mm) has increased over the past 140 years from 18 to 130p,g/kg. The estimated half-life of soil retention is considerable, for example 371-387 days for chrysene, 229-309 days for benzo[a]pyrene and 361-420 days for dibenzo[a,h]anthracene. PAHs containing two or three benzene rings are volatilised more rapidly. 

For six cata-condensed rings, there is the enthalpy of formation for dibenzo[, p] chrysene (31) of 574 kj/ mol for the gaseous species. Composed of two benzo-[c]phenanthrene subunits, this is a very strained species as indicated by the large endothermic isomerization enthalpy of 110 kj/mol from the estimated enthalpy of formation of the linear hexacene, 465.5 kJ/mol from eq 7b. Beyond six rings, there are no reported relevant measurements. 

Diels-Alder cycloaddition provides one of the most useful methods for the construction of polycyclic aromatic ring systems. With the use of maleic anhydride as dienophile, two additional carbon atoms may be fused to the bay region sites of some polycyclic arylenes to generate additional rings. For example, the first step in the synthesis of benzo[ghi]perylene 6 involves a Diels-Alder cycloaddition between perylene and maleic anhydride (Scheme 3.5) [19]. Aryne intermediates generated in situ also serve as dienophiles for Diels-Alder cycloadditions for example, reaction of 1,5-naphthadiyne (generated in situ from 2,6-dibromo-l,5-bis[(p-tolylsulfonyl)oxy] naphthalene with 2-methylisoindole forms an adduct which upon oxidation with m-chloroperbenzoic acid affords dibenzo[fe,k]chrysene 7 (Scheme 3.5) [20]. 

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