Pyrene chemical structure

Fig. 1 Chemical structures of pyrene conjugated at the 5 -end (5 -Py) and the 2 sugar position of uridine (PyU), and phenothiazine conjugated at the 5 -end of ODN (5 -Ptz)...

In 1775, Pursevil Pott first noted that the compounds associated with soot caused scrotal cancer in British chimney sweeps (] ). Not having modern methods of Instrumental analysis available to him, Pott was unable to specify the chemical structures of these compounds. It remained until 1933 before Cook et al. identified the exact structure of benzo[a]pyrene and demonstrated its carcinogenicity ( ). Thus, polycyclic aromatic hydrocarbons (PAH) are one of the few groups of compounds which are known to be carcinogenic to man. 

It is instructive to look at the refractive indices for a variety of chemical structures (Table 3.1.) What one quickly sees is that polar compounds are not the same as polarizable compounds. Indeed, polarizability is more related to chemical structure features like overall size (higher homologs within a compound family have greater polarizabilities), and presence of conjugated electron systems (benzene is more polarizable than hexane polarizability increases in the order benzene < naphthalene < pyrene). Finally, molecules with large atoms containing nonbonded electrons far from the nucleus (e.g., bromine, iodine) are generally more polarizable. After this brief diversion, now we continue to use refractive indices to estimate polarizabilities. 

Fig. 12 (a) Chemical structures of the fluorescent tracers synthesized for P-lactam antibiotic analysis PAAP [25,5/f, 6/ ]-3,3-dimethyl-7-oxo-6-[(pyren-l-ylacetyl) amino -4-thia-l-azabicyclo 3.2.0 heptane-2-carboxylic acid PBAP [2S,5/ ,6/J]-3,3-dimethyl-7-oxo-6-[(4-pyren-lylbutanoyl]amino]-4-thia-l-azabicyclo[3.2.0] heptane-2-carboxylic acid PAAM [2S,5/ ,6/ ]-3,3-dimethyl-7-oxo-6-( (2/f)-2-phenyl-2-[(pyren-l-ylacetyl)amino]ethanoyl amino)-4-thia-l-azabicyclo[3.2.0] heptane-2-carboxylic acid PBAM [2S,5/f,6/f]-3,3-dimethyl-7-oxo-6-( (2/f)-2-phenyl-2-[(pyren-l-ylbutanoyl)amino]ethanoyl ainino) l-thia-l-azabicyclo... 

Fig. 14 (a) Chemical structures of the polyphilic dispersion-promoter molecules, (b) Tailor-designed polyphilic molecules promoting CNT dispersion in the nematic host. Pyrene anchoring group (blue), mesogenic CB unit (dark red), flexible hydrocarbon or ethylene oxide spacer (green), and liquid crystal host (light red) [464]. (Reproduced by permission of The Royal Society of Chemistry)... 

Figure 9.11 Chemical structure of polycyclic aromatic hydrocarbons (PAHs) consisting of two or more benzene rings fused together, as shown in the PAHs naphthalene, anthracene, phenanthrene, and pyrene.

Fig. 8.4 Chemical structures of PAHs (a) naphthalene (b) fluorine (c) 9-methylanthracene (d) phenanthrene (e) fluoranthene (f) pyrene (g) benzo(a)pyrene 4...

The degree of bioavailability of organic compounds depends critically on their chemical structure which determines the kinds of interaction that may take place within the solid phase. For example, linear alkylbenzenesulfonates are readily desorbed from sediments, so that their biodegradability and potential toxicity is largely unaffected by the presence of sediments (Hand and Williams 1987). On the other hand, benzo[a]pyrene even though accessible to chemical extraction appears to be available to biota only to a limited extent (Varanasi et al. 1985). This is consistent with the view noted earlier that chemical extractability is not a useful measure of bioavailability for naturally aged samples as opposed to those which have been spiked with the contaminant (Kelsey et al. 1997). 

Fig. 9.19 Chemical structures of oxetane-functionalized emitters (a) low molecular weight pyrene-based emitter [46], (b) poly(fluorene-phenylene) copolymer [47], (c) spirobifluorene-cofluorene RGB emitter polymers [48], and (d) fluorene-bridged co-oligomers [50],...

Figure 9. Chemical structure of benz(a)pyrene (Manahan, 1994).

Figure 29 Chemical structure of the PSO-py and the expected G-quadruplexJnduced by binding. Pyrene excimer emission occurs in the presence oj K (Adapted from ref 56 with permission).

By HPLC the major reaction products of the BaP-D system were separated and tentative chemical structures were assigned to the peaks, based on the interpretation of the low and high resolution nS data as well as on comparison with reference spectra. The reaction mixture consisted mainly of ring-opened compounds such as dialdehyde and dicarboxylic acid, but also contained disubstitution products such as diphenols and quinones. The benzo(de)anthracene-7-one 3,4-dicarboxylic acid found in the reaction mixture is probably the precursor to the benzo(de)anthracene-7-one, detected by Sawicki (48) in the extract of ambient aerosols. The benzo(a)pyrene quinones were discovered in ambient air by Pierce and Katz (34). 

Figure 6.4 Upper panel the chemical structure of 1,1 -bis-pyrene butyoxyl-/ -xylene (bis-pyrene) lower panel schematic illustration of the molecular tweezers approach for the post-production separation of metallic and semiconducting SWNTs with the use of bis-pyrene.

In the selection of a raw material, availability and chemical nature are deciding factors. Olefinic and aliphatic chemicals such as ethylene, propylene and methanol are therefore produced from crude oil fractions and suitable natural gas, whereas polynuclear aromatics such as naphthalene, anthracene and pyrene are recovered almost exclusively from coal-derived raw materials. Mononuclear aromatics such as benzene, toluene and xylene occupy a medial position, being obtainable from both crude oil and coal feedstocks. Renewable raw materials are, owing to their chemical structure, particularly suitable for the production of compounds containing oxygen. 

Figure 12.18 Chemical structures of boronic acid-appended pyrene (B-dye), dansyl-diethylenetriamine (G-dye), and rhodamine B (R-dye).

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