Polycyclic aromatic hydrocarbon molecular properties

Govers, H., Ruepert, C., Aiking, H. (1984) Quantitative structure-activity relationships for polycyclic aromatic hydrocarbons Correlation between molecular connectivity, physico-chemical properties, bioconcentration and toxicity in Daphnia pulex. Chemosphere 13, 227-236. 

Analytical Properties y-Cyclodextrin (cyclooctylamalyose), reverse phase separation of stereoisomers of polycyclic aromatic hydrocarbons the substrate has eight glucose units and has a relative molecular mass of 1297 the cavity has a diameter of 0.59 nm, and the substrate has a water solubility of 23.2 g/ml Reference 13-28... 

Such a molecule can be stabilized by a system of delocalized Ji-electrons, which is closed into a toroid of 10 aromatic rings. Reactive sites are four CH groups, which are at the ends of this molecular tube. Such substances belong apparently to a new class of organic compounds, which is intermediate between planar polycyclic aromatic hydrocarbons and three-dimensional fullerenes, nanotubes. Quantum-chemical calculations of the electronic and spatial structure of C32H8 and some other molecules indicate that they have an increased reactivity and semiconductor properties. 

Hites RA, Simonsick WJ (1987) Calculated molecular properties of polycyclic aromatic hydrocarbons, Elsevier, Amsterdam... 

H. Covers, C. Ruepert, and H. Aiking, Chentosphere, 13, 227 (1984). Quantitative Structure-Activity Relationships for Polycyclic Aromatic Hydrocarbons Correlation Between Molecular Connectivity, Physicochemical Properties, Bioconcentration and Toxicity in Daphnia pulex. 

R.A. Hites and W.J. Simonsick, Jr., Calculated Molecular Properties of Polycyclic Aromatic Hydrocarbons... 

Table 5.5 Molecular properties of polycyclic aromatic hydrocarbons measured on a model silanol phase. Reproduced by permission of Taylor and Francis, ref. 17.

In most cases, the difference in retention times between two analytes is governed by differences in physical properties such as polarity. For example, a more polar analyte will have a higher affinity to reside in the mobile phase and, therefore, have a shorter retention time. However, many RPLC systems have the ability to separate analytes that have very similar chemical functionalities and physical properties, but differ only slightly in molecular shape. This ability, termed shape selectivity, is typically applied in the context of separating the geometric isomers of rigid molecules, such as polycyclic aromatic hydrocarbons (PAHs), among others. However, the separation of alkane isomers illustrated in Fig. 2 is also a form of shape selectivity. 

Without interactions with potential host molecules and in diluted solutions to avoid excimeric formations, pyrene presents in solution an intense and anisotropic fluorescence, as well as a high fluorescence quantum yield [34-37], Direct evidence of ground-state interactions of pyrene with potential host molecules is provided by the emission spectra. The vibrational structure of the emission spectrum of pyrene is constituted by five fine peaks, named I, I2, h, I4, and I5 (Fig. 13.2) [38]. An increase of the intensity of peak Ii is observed in polar solvents, while I, is solvent insensitive. Thus, the evolution of the ratio of intensities /1//3 gives information on the evolution of the polarity of the environment close to molecular pyrene, and consequently on the encapsulation of this guest in a host molecular or supramolecular object [39]. This sensitivity of pyrene, and of peri-fused polycyclic aromatic hydrocarbon molecules in general, to the polarity of the environment is a photophysic property that is extensively used to study host-guest interactions [40]. 

Acute toxicity in fish, bioconcentration in fish, chlorinated hydrocarbons, chlorinated phenols, molecular connectivity indices, molecular topology, nonempirical quantitative modelling of environmental properties, polycyclic aromatic hydrocarbons, quantitative structure activity correlations, soil sorption, Pimephales promelas, fathead minnow, connectivity indices, sheepshead minnows, Cyprinodon variegatus. 

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