Structure Correlation, the Chemical Point of View

In the preceding chapters we have seen how to define and describe the structure of a molecule or molecular fragment (Chapters 1 and 2), how to retrieve the relevant information from electronic databases (Chapter 3) and how to analyze this information with a variety of statistical methods (Chapter 4). Fragment definition, data retrieval and statistical analysis in structure correlation have their analogs in ordinary chemical experiments First a problem is identified, then the data are acquired from an appropriate experiment, filtered to distinguish the relevant from the irrelevant, and processed into a clear summary form. However, this is not the final step. The data still need to be understood. 

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Structure Correlation the Chemical Point of View 171 D=lDiSi. (5.11)... 

The lipophilicity and specific surface area of a similar set of synthetic dyes was also determined on an alumina-based RP-TLC stationary phase and the linear relationship between the two hydrophobicity parameters was calculated. The result of the calculation is depicted in Fig. 3.6. The good correlation between these physicochemical parameters indicated that from the chromatographic point of view these compounds behave as a homologous series of analytes, however, their chemical structures are markedly different [87],... 

Without doubt, the advent of carbon nanotubes has opened up iimovative perspectives for research and development of carbon electrodes. In this chapter, we have attempted to highlight the electrochemical properties of carbon nanotubes by rooting them mainly on their structural, electronic and chemical properties. If chirality of SWNTs could be controlled, it would be possible to probe electrochemically the unique electronic properties of the tubes with their corresponding unique DOS distribution and establish direct correlations between electronic structure and electrochemistry. However, so far, most of their electrochemical applications are based on ensembles of CNTs (MWNTs or SWNTs) in thin films supported on conductive surfaces or composites. Such ensembles, not so well defined from the structural point of view, contain a mixture of tubes with different diameters and DOS... 

The observed chemical shifts were described in terms of the structural environment of the observed nuclei using the correspondence between the experimental chemical shifts and coordination described in Table 10.3 and established at room temperature for solid stable compounds. From 18 to 50% AIF3, the average coordination number of aluminum with fluorine decreases from 5.5 to 4 and that of sodium increases from 8.5 to 11. The correlation between chemical shifts of Na and A1 indicates that these melts can be described from the Al-F as well as from the Na-F coordination point of view. 

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