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Intrinsic deuterium isotope effects on NMR chemical shifts of hydrogen bonded systems

Hansen P.

Nukleonika

2002

Vol. 47,suppl.1

37-42

This mini review describes intrinsic deuterium isotope effects on 13C chemical shifts of rigid hydrogen bonded compounds primarily in solution. The steric effects of intramolecularly hydrogen bonded compounds are dissected into different bond interactions leading either to steric compression or to steric twist. One-bond isotope effects involving CH(D) bonds are analyzed in terms of substituent effects and the question is raised whether isotope effects can be useful in the study of CHhydrogen bonds.

Solvent-Dependent Deuterium Isotope Effects in the 15N NMR Spectra of an Ammonium Ion

Wielogórska E., Jackowski K.

Polish Journal of Chemistry

2000

Vol. 74, nr 4

567-572

The reduced coupling constants have been estimated to present isotope effects in the spin-spin coupling constants. The latter isotope effects are fairly small.

Deuterium Isotope Effects of 0-Hydroxythioamides, Thiazolines and 5-Acyl-2-thiobarbituric Acids

Hansen P., Duus F., Neumann R., Wesolowska A., Sosnicki J., Jagodzinski T.

Polish Journal of Chemistry

2000

Vol. 74, nr 3

409-420

Deuterium isotope effects on 13C chemical schifts are studied in a series of o-hydroxythioamides, 2 delta-thiazolines and enolic 5-acyl-2-thiobabituric acids. Novel 2-hydroxy-1-thiocarboxamide naphthalenes show steric isotope effects of opposite sign to those observed in 2-hydroxy-1-acetylnaphthalenes and pyrenes. The o-hydroxyaromatic 2delta-thiazolines show tautometric behaviour and accordingly large isotope effects. Tautomerism of these and the thioamides are discussed in relation to structure. Intramolecular hydrogen bonding of non-RAHB type show only weak effects. The enolic mono N-alkyl 5-acyl 2-thiobarbituric acids show two isomers, both of which are involved in enol-enol tautomerism.