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Intramolecular Hydrogen Bond Reverting the Solvent Effect on Phosphorus Hyperfine Coupling Constants of β‐Phosphorylated Nitroxides
Author(s) -
Audran Gérard,
Bosco Lionel,
Brémond Paul,
Butscher Teddy,
Marque Sylvain R. A.,
Viel Stéphane
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201600647
Subject(s) - chemistry , intramolecular force , hydrogen bond , photochemistry , solvent , polarizability , moiety , solvent effects , acceptor , nitroxide mediated radical polymerization , stereochemistry , molecule , organic chemistry , physics , radical polymerization , condensed matter physics , polymer , copolymer
Recently, we reported a dramatic solvent effect on the phosphorus hyperfine coupling constant a P of β‐phosphorylated six‐membered ring nitroxides, that is, approximately 25 G of difference in a P from n ‐hexane to water ( Org. Biomol. Chem . 2016 , 14 , —1228‐1292). In this article, we report on the effect of intramolecular hydrogen bonding (IHB) in three nitroxides exhibiting IHB between the hydroxyl and diethylphosphoryl groups and one exhibiting IHB between the hydroxyl group and the nitroxyl moiety. It is observed that for the first three nitroxides, a P increases with increasing polarity/polarizability and hydrogen bond donor (HBD) properties of the solvent (π* and α , respectively)—in sharp contrast to the data reported in the literature—and for the last nitroxide, a P decreases with π* and α . In fact, the occurrence of IHB induces a large strain, its suppression by hydrogen bond acceptor (HBA) solvents affords an increase in a P .