Deuterium Isotope Effects on Chemical Shifts of Ammonium Ions: A Solid State NMR Study

Deuterium isotope effects on chemical shifts are measured in ammonium halides in the solid state using both enriched salts and natural abundance materials. The effects are correlated to chemical shifts and to N···X distances. The deuterium isotope effects on chemical shifts in the solid state are discussed in relation to effects observed in solution. No NH couplings are seen due to fast rotation in the solid, which leads to self-decoupling, whereas ND couplings are present.