Determination of positional weighting factors for the Swain and Lupton substituent constants f and r was written by Williams, S. G.;Norrington, F. E.. And the article was included in Journal of the American Chemical Society in 1976.Product Details of 5344-49-0 This article mentions the following:
Addnl. data considered in abstracting and indexing are available from a source cited in the original document. Previous workers (Swain, C. G. and Lupton, E. C., 1968) have shown that Hammett’s substituent constant σ and related parameters can all be expressed as a linear combination of two principal components F and R, which represent resp. the field and resonance effects of the substituent without regard for its position in the mol. A statistical anal. of data from 45 reaction series was carried out to determine positional weighting factors f and r for F and R, to enable the latter to be applied to the ortho, meta, and para positions of a benzene ring simultaneously. The fpara and rpara were both defined as 1.000. Fmeta was 0.980 (not significantly different from 1.000), fortho 1.248, rmeta 0.347, and rortho 0.863. These values agree roughly with the ad hoc assumptions made hitherto by classical organic chemists and enable good correlations to be found between physicochem. properties of the side chain and substituent parameters of mixed or multiply substituted populations of benzenoid compounds They also demonstrate that generalized σ-type parameters may be successfully applied to the ortho position, although the correlation with observed data is less good than with the meta and para positions due, no doubt, to the proximity of the substituent to the side chain of the mol. In the experiment, the researchers used many compounds, for example, 2-Chloro-6-nitrobenzoic acid (cas: 5344-49-0Product Details of 5344-49-0).
2-Chloro-6-nitrobenzoic acid (cas: 5344-49-0) belongs to organic chlorides. Organic chlorides can be used in production of: PVC, pesticides, chloromethane, teflon, insulators. Alkyl chlorides are versatile building blocks in organic chemistry. While alkyl bromides and iodides are more reactive, alkyl chlorides tend to be less expensive and more readily available.Product Details of 5344-49-0
Referemce:
Chloride – Wikipedia,
Chlorides – an overview | ScienceDirect Topics