Consequences of the nonmonotonic variation of XH frequencies with ionic character on the frequency-Hammett constant relation was written by Laurence, Christian;Berthelot, Michel. And the article was included in Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy in 1978.Reference of 6515-58-8 This article mentions the following:
A nonmonotonic variation of XH stretching frequencies with ionic character is illustrated for RC6H4XH (X = O, CH2O, NH, NMe, CH2NH, and S) where m– and p-substituents are expected to affect the polarity of the XH bond. It is explained why ν(XH)-Hammett constant relations are not always linear. Attempts to make the relations linear are unsuccessful. In the experiment, the researchers used many compounds, for example, 3-(Bromomethyl)benzoic acid (cas: 6515-58-8Reference of 6515-58-8).
3-(Bromomethyl)benzoic acid (cas: 6515-58-8) belongs to organobromine compounds. Bromo compounds are employed in a variety of metal-catalyzed coupling reactions. They are also ideal candidates for the synthesis of Grignard reagents that have wide-applicability in organic synthesis. alpha-Bromoesters are employed in the Reformatsky reaction for the synthesis of beta-hydroxyesters. Many of the alkyl bromine derivatives are excellent alkylating agents since bromides are good leaving groups. Tribromides, like tetrabutylammonium tribromide, are used as a solid source of bromine. N-bromosuccimide (NBS) is used for the selective bromination of allylic bonds.Reference of 6515-58-8
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary