Aromatic structure-function characteristics

Structure-Function Characteristics of Aromatic Amine-DNA Adducts... 

In spite of these difficulties with DOM chemistry, environmental chemists are frequently asked what molecular structures within the mixture are responsible for contaminant binding, haloform production, light attenuation, protonation characteristics, and other problems of environmental relevance. The chemist usually hypothesizes that DOM features such as aromaticity, polarity, functional-group content and configuration, molecular interactions, and molecular size can explain the observed phenomena. However, models of DOM (or DOM-fraction) structures must be based on average-mixture analyses to support these hypotheses. Such models represent average properties of thousands to millions of mixed compounds. 

The resulting novolak polyols, in spite of their low functionalities and low hydroxyl numbers, give rigid PU foams with a very uniform cellular structure, with excellent physico-mechanical, thermal and fire proofing properties and good dimensional stability, characteristics which are associated with the high aromatic structure of novolak polyols. 

A macrocyclic resorcin[4]arene with four hydrophobic substituents in the axial position provides an ion-conducting molecular pore by tail-to-tail dimerization.Because the pore size and characteristics of the entry way are defined explicitly by the molecule, only one conductance level is observed. The relatively simple structure is amenable to systematic structural modifications and is, therefore, appropriate in establishing the structure-function relationships. When a methyl ether derivative of cholic acid was employed as the axial substituent,the conductance was increased by 50% to 9.9 pS, compared with the value 6.1 pS observed for 1 with simple alkyl substituents. The cation and anion selectivity ratio Pk/Pc was 20 for 2. showing a significantly larger selectivity factor compared to 8 for 1. A hydrophilic molecular plane of methoxy substituents certainly contributes to the increase of conductance and a higher cation and anion selectivity by the arrangement of a more hydrophilic environment at the central pore. Both ion channels exhibited moderate preferences compared to Na by a facior of ca. 3. The aromatic moiety provides a weak electric field... 

The organic chemical structural types believed to be characteristic of coals include complex polycyclic aromatic ring systems with connecting bridges and varied oxygen-, sulfur-, and nitrogen-containing functionalities. 

Encapsulation of different entities inside the CNT channel stands alone as an alternative noncovalent functionalization approach. Many studies on the filling of carbon nanotubes with ions or molecules focus on how the presence of these fillers affects the physical properties of the tubes. From a different point of view, confinement of materials inside the cylindrical structure could be regarded as a way to protect such materials from the external environment, with the tubes acting as a nanoreactor or a nanotransporter. It is fascinating to envision specific reactions between molecules occurring inside the aromatic cylindrical framework, tailored by CNT characteristic parameters such as diameter, affinity towards specific molecules, etc. 

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