title: The β-phosphorus hyperfine coupling constant in nitroxides: 6. Solvent effects in non-cyclic nitroxides.
abstract: In two recent articles (Org. Biomol. Chem., 2015 and 2016), we showed that changes in the phosphorus hyperfine coupling constant aP 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 aP of persistent non-cyclic β-phosphorylated nitroxides decrease with the normalized polarity Reichardt's constant E(N)T. The Koppel-Palm and Kalmet-Abboud-Taft relationships were applied to gain deeper insight into the effects influencing aN and aP: polarity/polarizability, hydrogen bond donor properties, and the structuredness of the cybotactic region.
authors.affiliation: Aix-Marseille Université, CNRS-UMR 7273, ICR, case 541, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France. paul.brémond@univ-amu.fr sylvain.marque@univ-amu.fr g.audran@univ-amu.fr.
authors.forename: Gérard
authors.initials: G
authors.lastname: Audran
authors.affiliation: Aix-Marseille Université, CNRS-UMR 7273, ICR, case 541, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France. paul.brémond@univ-amu.fr sylvain.marque@univ-amu.fr g.audran@univ-amu.fr.
authors.forename: Lionel
authors.initials: L
authors.lastname: Bosco
authors.affiliation: Aix-Marseille Université, CNRS-UMR 7273, ICR, case 541, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France. paul.brémond@univ-amu.fr sylvain.marque@univ-amu.fr g.audran@univ-amu.fr.
authors.forename: Paulin
authors.initials: P
authors.lastname: Nkolo
authors.affiliation: Université des Sciences et Technique de Masuku, Laboratoire de Substances Naturelles et des Syntheses Organometalliques, B.P. 493 Franceville, Gabon.
authors.forename: Raphael
authors.initials: R
authors.lastname: Bikanga
authors.affiliation: Aix-Marseille Université, CNRS-UMR 7273, ICR, case 541, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France. paul.brémond@univ-amu.fr sylvain.marque@univ-amu.fr g.audran@univ-amu.fr.
authors.forename: Paul
authors.initials: P
authors.lastname: Brémond
authors.affiliation: Aix-Marseille Université, CNRS-UMR 7273, ICR, case 541, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France. paul.brémond@univ-amu.fr sylvain.marque@univ-amu.fr g.audran@univ-amu.fr.
authors.forename: Teddy
authors.initials: T
authors.lastname: Butscher
authors.affiliation: Aix-Marseille Université, CNRS-UMR 7273, ICR, case 541, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France. paul.brémond@univ-amu.fr sylvain.marque@univ-amu.fr g.audran@univ-amu.fr and N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Pr. Lavrentjeva 9, 630090 Novosibirsk, Russia.
authors.forename: Sylvain R A
authors.initials: SR
authors.lastname: Marque