Deuterium isotope effects on 13C chemical shifts of negatively charged NH.N systems

Poul Erik Hansen, Mariusz Pietrzak, Eugeniusz Grech, J. Nowicka-Scheibe

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Deuterium isotope effects on 13C chemical shifts are investigated in anions of 1,8-bis(4-toluenesulphonamido)naphthalenes together with N,N-(naphthalene-1,8-diyl)bis(2,2,2-trifluoracetamide) all with bis(1,8-dimethylamino)napthaleneH+ as counter ion. These compounds represent both “static” and equilibrium cases. NMR assignments of the former have been revised. The NH proton is deuteriated. The isotope effects on 13C chemical shifts are rather unusual in these strongly hydrogen bonded systems between a NH and a negatively charged nitrogen atom. The formal four-bond effects are found to be negative indicating transmission via the hydrogen bond. In addition, unusual long range effects are seen. Structures, 1H and 13C NMR chemical shifts and changes in nuclear shieldings upon deuteriation are calculated using density functional theory methods
TidsskriftMagnetic Resonance in Chemistry
Udgave nummer11
Sider (fra-til)683-689
Antal sider7
StatusUdgivet - 2013


  • Isotope effects
  • NMR
  • Hydrogen bonding

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