Aromatic carcinogens energy

Energy Refined Polymer Models of DNA Modified by Polycyclic Aromatic Carcinogens. ... 

Benzo[a]pyrene, a molecule with five, fused, hexagonal rings, is among the most carcinogenic of the polycyclic aromatic hydrocarbons (PAHs). Such biological activity may be related to the electronic structure of benzo[a]pyrene and its metabolites. Ionization energies of these molecules therefore have been investigated with photoelectron spectroscopy [28]. 

At low enough temperatures vibrational fine structure of aromatic chromophores may be well resolved, especially if they are embedded in a suitable matrix such as argon or N2, which is deposited on a transparent surface at 15 K. This matrix isolation spectroscopy77166 may reveal differences in spectra of conformers or, as in Fig. 23-16, of tautomers. In the latter example the IR spectra of the well-known amino-oxo and amino-hydroxy tautomers of cytosine can both be seen in the matrix isolation IR spectrum. Figure 23-16 is an IR spectrum, but at low temperatures electronic absorption spectra may display sharp vibrational structure. For example, aromatic hydrocarbons dissolved in n-heptane or n-octane and frozen often have absorption spectra, and therefore fluorescence excitation spectra, which often consist of very narrow lines. A laser can be tuned to excite only one line in the absorption spectrum. For example, in the spectrum of the carcinogen ll-methylbenz(a)anthrene in frozen octane three major transitions arise because there are three different environments for the molecule. Excitation of these lines separately yields distinctly different emission spectra.77 Likewise, in complex mixtures of different hydrocarbons emission can be excited from each one at will and can be used for estimation of amounts. Other related methods of energy-... 

Combustion processes of fossil fuels are currently the main source of energy generation. It is well known that, in these processes, pollutants -such as SO2, NOx and CO2 and CO-are emitted to the atmosphere. Organic emissions, whose harmful nature has become the cause of growing concern, are another important source of pollution released in these processes. In fact. Polycyclic Aromatic Hydrocarbons (PAH) have been widely studied and their carcinogenic and mutagenic potential has been a matter of considerable concern [1,2]. These emissions can be minimized by combustion optimization but not completely... 

D.D. Morgan, D. Warshawsky, T. Atkinson (1977). The relationship between carcinogenic activities of polycyclic aromatic hydrocarbons and their singlet, triplet, and singlet-triplet splitting energies and phosphorescence lifetimes. Photochem. Photo-bioL, 25, 31-38. 

The last general category—namely, the reaction of ozone with aromatic hydrocarbons, has received an enormous amount of attention by ozone chemists. Most of this attention has concerned rate and reactivity studies in an attempt to correlate these experimental quantities with some known parameters of the hydrocarbons. Several reactivity correlations have been proposed, including those with bond localization energy, atom localization energies, and oxidation-reduction potentials. This category is also represented by a paper in this section, in which a possible correlation between ozone reactivity and carcinogenicity of some polycyclic aromatic compounds is explored. 

Sung and Lazar [85] provided confirmation of Mason s [79, 80] controversial hypothesis of hydrocarbon binding to proteins, which is based on the the so-called Brillouin—Bloch bands in proteins (primarily the delocalised bond in peptide moieties) the energy difference between the highest occupied electron band and the first unoccupied (so-called conduction) band is approximately 3 eV. Mason observed that, for carcinogenicity in polycyclic aromatic hydrocar-... 

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