Selwood

It may be of interest to readers that all three methods mentioned above resulted in the same optimal subset of descriptors for the well-known Selwood dataset, which has become a de-facto standard in testing new approaches in this field [20]. 

P.W. Selwood, Chemisorption and Magnetization, Academic Press, New York (1975). 

Hartzoulakis B, Rossiter S, Gill H, O Hara B, Steinke E, Gane PJ, Hurtado-Guerrero R, Leiper JM, Vallance P, Rust JM, Selwood DL (2007) Bioorg Med Chem Lett 17 3953... 

Parker, A. and B. W. Selwood (1983), Sediment Diagenesis, Kluwer, New York. 

The temperature dependence of the extent of adsorption was not interpreted, except that the results were considered to be consistent with the magnetic measurements of Selwood (see Section II,C) which indicate that the number of carbon-metal bonds between adsorbed species and the surface increases threefold between 120°and 200°C due to extensive dissociative chemisorption. The authors proposed that two forms of chemisorbed benzene exist at the nickel surface, (i) an associatively adsorbed form which can be displaced by further benzene, and which may be w- or hexa-dissociatively adsorbed form that requires the presence of hydrogen to bring about its removal from the surface. 

The color of the quinonoid compounds that may be obtained by disproportionation can be sufficiently like that of the radicals to cause confusion if visual observation or broad-band spectrophotometry is used.11 For example, Preckel and Selwood, using paramagnetism as a measure of the amount of radical, reported that solutions of triphenyl-methyl derivatives more or less rapidly lost their paramagnetism. The decomposed solutions were still highly colored, but the color was no longer dependent on the temperature as it is in the case of a radical-dimer equilibrium mixture. What is more striking, and an even more subtle and dirtier trick on the part of nature, is the fact that Preckel and Selwood s non-paramagnetic solutions were still rapidly bleached by exposure to the air. It is clear that radical-like reactivity is not a safe criterion for the presence of radicals. It is also clear that the ebullioscopic method is particularly unsatisfactory in view of the excellent chance for decomposition. 

---