Properties of aromatic hydrocarbon

An important property of aromatic hydrocarbons is that they are much more stable and less reactive than other unsaturated compounds Ben zene for example does not react with many of the reagents that react rapidly with alkenes When reaction does take place substitution rather than addition is observed The Kekule formulas for benzene seem mcon sistent with its low reactivity and with the fact that all of the C—C bonds m benzene are the same length (140 pm)... 

Although the correlation between structural properties of aromatic hydrocarbons and their carcinogenic properties proved to be much more complicated than was hoped, this type of calculation opened the door to the application of quantum chemistry to biological systems. The calculations are applied not only to cancer-related problems, but also to the study of amino acids, peptides, nucleotides, and other than anti-cancer therapeutic agents. 

J. H. Magill,/. Chem. Phys., 47,2802 (1967). Physical Properties of Aromatic Hydrocarbons. 

Armarego109 has determined the pAa values of indolizines and aza-indolizines from their ultraviolet spectra. He found that indolizine itself has the same basic strength as a-naphthylamine (pAa 3.9) and that a methyl substituent increases the pAa by two to three units. Mason and Smith,110 studying the fluorescence spectra of various aromatic nuclei including indolizine, found no evidence to support the prediction that acid-base properties of aromatic hydrocarbons in the first electronic excited state should differ from those in the ground state. 

Northrop, D.C. Simpson, O. Electronic properties of aromatic hydrocarbon II, fluorescence transfer in solid solutions. Proc. Phys. Soc. (Lond.) 1956, A234, 815. 

Describe the chief physical properties of aromatic hydrocarbons. 

PHYSICAL PROPERTIES OF AROMATIC HYDROCARBONS. II. SOLIDIFICATION BEHAVIOR OF 1,3,5-TRI.ALPHA-NAPHTHYL-BENZENE. 

The biological properties of dioxin include an ability to bind to a protein known as the AH (aromatic hydrocarbon) receptor Dioxin IS not a hydrocarbon but it shares a certain structural property with aromatic hydrocarbons Try constructing molecular models of dioxin and anthracene to see these similarities... 

It may also be represented as a hexagon with a circle in the middle. The circle is a symbol of the n cloud encircling the benzene ring. The delocalized electrons associated with the benzene ring impart very special properties to aromatic hydrocarbons. They have chemical properties of single-bond compounds such as paraffin hydrocarbons and doublebond compounds such as olefins, as well as many properties of their own. 

Beneficial Micro Reactor Properties for the Photocyanation of Aromatic Hydrocarbons... 

In any event, between 1951 and 1975, no papers appeared on polysilane high polymers. However, linear permethylpolysilanes of the type MelSiMezhiMe were prepared and studied, especially by Kumada and his students,(5) and cyclic polysilanes were being investigated in several laboratories.(6,7) Studies of the permethyl-cyclosilanes, (Me2Si)n where n = 4 to 7, showed that these compounds exhibit remarkable delocalization of the ring sigma electrons, and so have electronic properties somewhat like those of aromatic hydrocarbons.(6)... 

Industrial applications of zeolites cover a broad range of technological processes from oil upgrading, via petrochemical transformations up to synthesis of fine chemicals [1,2]. These processes clearly benefit from zeolite well-defined microporous structures providing a possibility of reaction control via shape selectivity [3,4] and acidity [5]. Catalytic reactions, namely transformations of aromatic hydrocarbons via alkylation, isomerization, disproportionation and transalkylation [2], are not only of industrial importance but can also be used to assess the structural features of zeolites [6] especially when combined with the investigation of their acidic properties [7]. A high diversity of zeolitic structures provides us with the opportunity to correlate the acidity, activity and selectivity of different structural types of zeolites. 

The redox properties of cyclic polysilanes are interesting because they resemble those of aromatic hydrocarbons. For instance, cyclic polysilanes can be reduced to anion radicals or oxidized to cation radicals. ESR spectra for both the cation and anion radicals indicate that the unpaired electron is fully delocalized over the ring [17,19,20]. The aromatic properties of the cyclic polysilanes are ascribed to a high energy delocalized HOMO and a relatively low energy LUMO. Because the HOMO and LUMO levels lie at similar level to those of benzene, cyclic polysilanes can serve either as electron donors or electron acceptors. 

Among oxo-metals, osmium tetroxide is a particularly intriguing oxidant since it is known to oxidize various types of alkenes rapidly, but it nonetheless eschews the electron-rich aromatic hydrocarbons like benzene and naphthalene (Criegee et al., 1942 Schroder, 1980). Such selectivities do not obviously derive from differences in the donor properties of the hydrocarbons since the oxidation (ionization) potentials of arenes are actually less than those of alkenes. The similarity in the electronic interactions of arenes and alkenes towards osmium tetroxide relates to the series of electron donor-acceptor (EDA) complexes formed with both types of hydrocarbons (26). Common to both arenes and alkenes is the immediate appearance of similar colours that are diagnostic of charge-transfer absorp-... 

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