The β-phosphorus hyperfine coupling constant in nitroxides: 6. Solvent effects in non-cyclic nitroxides. Issue 15 (17th March 2016)

• Record Type: Journal Article
• Authors: Audran, Gérard; Bosco, Lionel; Nkolo, Paulin; Bikanga, Raphael; Brémond, Paul; Butscher, Teddy; Marque, Sylvain R. A.
• Is Part Of: Organic & biomolecular chemistry. Volume 14:Issue 15(2016)
• Page Start: 3729
• Page End: 3743
• Publication Date: 2016-03-17
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c6ob00359a
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : The impact of the solvent on a P and a N decreases strikingly upon increasing both the bulkiness and the polarity of the substituents around the nitroxyl moiety. Abstract : In two recent articles ( Org. Biomol. Chem., 2015 and 2016), we showed that changes in the phosphorus hyperfine coupling constant a P at position β in β-phosphorylated nitroxides can be dramatic. Such changes were applied to the titration of water in organic solvents and conversely of organic solvents in water. One of the molecules tested was a non-cyclic nitroxide meaning that a thorough investigation of the solvent effect on the EPR hyperfine coupling constant is timely due. In this article, we show that the a P of persistent non-cyclic β-phosphorylated nitroxides decrease with the normalized polarity Reichardt's constant E NT. The Koppel–Palm and Kalmet–Abboud–Taft relationships were applied to gain deeper insight into the effects influencing a N and a P : polarity/polarizability, hydrogen bond donor properties, and the structuredness of the cybotactic region.