Pyrene electronic properties

In order to gain more detailed information about the physical binding of hydrocarbon metabolites to DNA, studies have also been carried out with model compounds which have many of the steric and electronic properties of carcinogenic epoxides but no reactive epoxide group. The use of nonreactive model compounds permits the clear separation of physical binding interactions from reactive interactions. Benzo[a]pyrene metabolite model compounds which have been examined include 7-hydroxy-7,8,9,10-tetrahydro-BP (4), and cis (4 ) and trans-7,8-dihydroxy-7,8,9,10-tetrahydro-BP (9). 

V. Librando et al., Electronic properties of some nitrobenzo[a]pyrene isomers A possible relationship to mutagenic activity. J. Mol. Model. 14, 489-497 (2008)... 

It has been reported that Cgo and its derivatives form optically transparent microscopic clusters in mixed solvents [25, 26]. Photoinduced electron-transfer and photoelectrochemical reactions using the C o clusters have been extensively reported because of the interesting properties of C o clusters [25,26]. The M F Es on the decay of the radical pair between a Cgo cluster anion and a pyrene cation have been observed in a micellar system [63]. However, the MFEs on the photoinduced electron-transfer reactions using the Cgo cluster in mixed solvents have not yet been studied. 

Photo-oxidation of LCV by the Pyrene-Bonded Film. The surface properties and structure of these systems should be related to the sensitizer efficiency of pyrenyl groups. Pyrene is a good sensitizer for the oxidative color formation of LCV. The singlet excited state of Py acts as an electron acceptor bringing about one electron oxidation of LCV+. The unit processes are considered as... 

With the aim of preparing photoinduced electron transfer devices or simply to be used as fluorescent reporter groups, the synthesis and utility of pyrene-L-alanine have been reported on several occasions. Regarding the development of charge-transfer devices, it was shown that intramolecular electron transfer occurred in 310- and a-helical peptidic systems, such as 182 and 185, between a pyrene and a dimethylaminophenyl chromophore (Scheme 51).[95 101] The rates depend on the relative orientation of the chromophoric side chains and on the framework conformation. Therefore, the preparation of tailor-made charge-transfer devices with tunable properties can be envisaged. 

Although this classification of electron donors and acceptors often proves useful, these terms are only relative [14], under appropriate conditions, such as when the highest occupied molecular orbital is located between the orbitals of the potential donor and acceptor. Any molecule can exhibit both electron-donor and electron-acceptor properties [15]. Thus dimethyl-alloxazine, for example, acts as a donor to the strong acceptor TCNE (tetracyanoethylene) and as an acceptor to the strong donor pyrene [16]. This dual character applies particularly to iT-bonded molecules and is es-... 

More work with other aromatic compounds will be necessary to verify this conclusion. However, the results for anthracene certainly suggest that the results obtained in the reaction are strongly dependent upon the aromatic substrate. The results obtained thus far also suggest that the reduction and subsequent alkylation of large polycyclic molecules, e.g., compounds such as pyrene, are not the most critical factors for the formation of soluble alkylation products. Studies of the molecular weight distributions and spectroscopic properties of the alkylation products obtained with different metals and different electron transfer agents are underway to resolve this issue. 

A set of fluorophores derived from naphthalene, phenanthrene, pyrene, phenazine and fluorene have been conjugated to the 5 -ends of DNA and RNA to compare their physico-chemical properties. Decreasing the Ji-electron density led to an enhancement in thermal stability, attributable to more favourable Jt-Ji interactions. Stability is further enhanced by using nitrated fluorophores. Fluorescent labelling of ODNs using oxyamino modified fluorescein has been reported by the incorporation into DNA of aldehyde functions. The aldehyde function was attached either at the 5 -end via a phosphate linker or internally via 8-mercaptobutanal. Reduction of the resulting oxime was not necessary. 

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