Pyrene and derivatives

Sullivan PD (1985) Free radical of benzo(a)pyrene and derivatives. Environ Health Perspect 64 283-295... 

Surface heterogeneity may be inferred from emission studies such as those studies by de Schrijver and co-workers on P and on R adsorbed on clay minerals [197,198]. In the case of adsorbed pyrene and its derivatives, there is considerable evidence for surface mobility (on clays, metal oxides, sulfides), as from the work of Thomas [199], de Mayo and co-workers [200], Singer [201] and Stahlberg et al. [202]. There has also been evidence for ground-state bimolecular association of adsorbed pyrene [66,203]. The sensitivity of pyrene to the polarity of its environment allows its use as a probe of surface polarity [204,205]. Pyrene or ofter emitters may be used as probes to study the structure of an adsorbate film, as in the case of Triton X-100 on silica [206], sodium dodecyl sulfate at the alumina surface [207] and hexadecyltrimethylammonium chloride adsorbed onto silver electrodes from water and dimethylformamide [208]. In all cases progressive structural changes were concluded to occur with increasing surfactant adsorption. 

In the present study, the liquefaction activities of pyrene, its derivatives, and decacyclene with coals of several ranks are studied to ascertain the previous ideas of liquefaction mechanism and to develop novel liquefaction process under atmospheric pressure. The coals used in the present study are non-fusible or fusible at relatively high temperature, and then gave small liquefaction yield with pyrene of a non-solvoly-tic solvent at 370°C. 

Since the same dye molecules can serve as both donors and acceptors and the transfer efficiency depends on the spectral overlap between the emission spectrum of the donor and the absorption spectrum of the acceptor, this efficiency also depends on the Stokes shift [53]. Involvement of these effects depends strongly on the properties of the dye. Fluoresceins and rhodamines exhibit high homo-FRET efficiency and self-quenching pyrene and perylene derivatives, high homo-FRET but little self-quenching and luminescent metal complexes may not exhibit homo-FRET at all because of their very strong Stokes shifts. 

Montalti and co-workers studied dansyl [27] and pyrene [28] derivatives and found the fluorescence quantum yields and excited-state lifetime of these two dyes increased in DDSNs. They attributed the enhancements to the shielding effect from the quenchers or polar solvent in the suspension. Their studies also demonstrated that the lifetime of the doped dye molecules was also dependent on the size of the DDSNs. Small DDSNs had a larger population of the short-living moieties that were more sensitive to the environment outside the DDSN. In contrast, the large DDSN had a larger population of the long-living moieties that were not sensitive to the environment. 

Only the silica-based stationary phases with covalently bonded alkyl chain, cyano and propylamino ligands have found practical applications in HPLC. Besides these common ligands, the experimental use of naphthalene, pyrene and nitroaromatic as ligands has also been reported. Silica-based stationary phases with covalently bonded cyclodextrins or cyclodextrin derivatives have been frequently employed in the separation and quantitative determination of isomer pairs. 

The primary focus of the study by Guthrie and Pfaender [360] was to assess how biological activity influenced interactions of pyrene and pyrene derivatives with soil organic matter, by determining how microbial activity influenced associations between pyrene and particular SOM fractions over extended periods of time. Experiments were then conducted to determine if pyrene-SOM associations altered the pyrene bioavailability, and designed to... 

The mono- and diprotonated carbocations and the two-electron oxidation dications derived from parent pyrene and its nonalternant isomers azupyrene (dicyclo-penta[e/, /]heptalene) (DCPH) 72 and dicyclohepta[eJ,g /z]pentalene (DCHP) 73 were studied at the B3LYP/6-31G(d) level (Fig. 29). The most likely site(s) for mono-and diprotonation were determined based on relative arenium ion energies and the structures of the energetically most favored carbocations were determined by... 

Rather surprisingly the only polycyclic ring system to have found significant commercial application in FBAs is pyrene. The triazinyl derivative (3.64), which is synthesised by a Friedel-Crafts reaction between pyrene and 2-chloro-4,6-dimethoxy-l,3,5-triazine, is an important brightener for polyester and cellulose acetate. 

FIGURE 10.12 Absorption spectra in methanol of benzo[a]pyrene and its 1-, 3-, and 6-nitro derivatives (adapted from Pitts et al., 1978). 

Members of another class of powerful direct mutagens, four nitroazabenzo[a]pyrene derivatives, were identified by Sera and co-workers (1994) in the basic fraction of extracts of diesel exhaust and in ambient POM. Structures and direct mutagenic activities on strains TA98 and YG1024 (-S9 mix) of the 1- and 3-nitro-6-azabenzo[a]pyrenes and the 1- and 3-nitro-6-azabenzo[a]pyrene-7V-oxides are shown in Table 10.21 (Sera et al., 1992 Fukuhara et al., 1992). They have been measured in ambient air in Fukuoka, Japan, at concentrations of 1.1, 1.2, 0.8, and 0.3 ng/g, respec-... 

Sangaiah, R., and A. Gold, A Short and Convenient Synthesis of Cyclopenta[cd]pyrene and Its Oxygenated Derivatives, in Polynuclear Aromatic Hydrocarbons Mechanisms, Methods and Metabolism (M. Cooke and A. J. Dennis, Eds.), Eighth International Symposium on Polynuclear Aromatic Hydrocarbons, Bat-telle Press, Columbus, OH, 1985. 

Tokiwa, H., T. Otofuji, R. Nakagawa, K. Horikawa, T. Maeda, N. Sano, I. Izumi, and H. Otsuka, Dinitro Derivatives of Pyrene and Fluoranthene in Diesel Emission Particulates and Their Tumorigenicity in Mice and Rats, in Carcinogenic and Mutagenic Effects of Diesel Engine Exhaust (N. Ishinishi, A. Koizumi, R. O. McClellan, and W. Stober, Eds.), pp. 253-270, Elsevier, Amsterdam/New York, 1986. 

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