Model Polyaromatic Hydrocarbons Research Articles

Experimental design applied to a room-temperature phosphorimetric method for the determination of acenaphthene in a microemulsion

The room-temperature phosphorescence (RTP) of acenaphthene as a model polyaromatic hydrocarbon with stabilization using a microemulsion of an apolar solvent has been examined. A multivariate optimization approach using the type of central composite blocked cube-star design was carried out. These variables selection constitute the basis of a RTP method for the determination of acenaphthene (detection limit 4.6 ng ml −1; 2% relative standard deviation at 75 ng ml −1. The method has been applied to the determination of acenaphthene in sea water samples.

Chemistry of carbonization—I. A theoretical study of free radical formation from starting materials

The effect of size, shape, and aromaticity in the formation of radicals from model polyaromatic hydrocarbons (PAH) was theoretically studied using the MINDO/3 method. The results were interpreted in terms of hydrogen transfer on carbonization and liquefaction processes of coal-related compounds. Additives that donate or withdraw electrons were modeled by calculating negatively or positively charged systems. The results show that the hydrogen donating properties of PAHs increase with the increase of their molecular weights. The formation of anionic π-radicals is thermodynamically favored, contrary to cationic π-radicals. Negative charge favored the formation of low molecular weight radicals, and therefore, the hydrogen transfer from light to heavy PAHs. Positive charges, in general, do not facilitate the hydrogen transfer.

Synthesis of an aromatic hydrocarbon diol epoxide–cytosine adduct, 5′-O-(9-phenylxanthen-9-yl)-N4-[(±)-1β,2α,3α-triacetoxy-1,2,3,4-tetrahydro-4β-naphthyl]-2′-deoxycytidine, suitable for incorporation into synthetic oligodeoxyribonucleotides

The first total synthesis of a model polyaromatic hydrocarbon diol epoxide–cytosine adduct is described, suitable for incorporation into oligodeoxyribonucleotide synthesis. An approach to control the relative stereochemistry of the diol epoxide–nucleoside adduct is discussed. This synthesis yields 5′-O-(9-phenylxanthen-9-yl)-N4-[(±)-1β,2α,3α-triacetoxy-1,2,3,4-tetrahydro-4β-naphthyl]-2′-deoxycytidine as a mixture of diastereoisomers.