Deuterium isotope effects on 31P NMR parameters: hydrogen bonding in a solid urea–phosphoric acid adduct
Abstract
Long-range deuterium isotope effects on the 31P NMR shielding tensor were studied for the perdeuteriated urea–phosphoric acid adduct (ND2)2CO · D3PO4. This complex contains a short hydrogen bond linking its molecular components, for which a single-minimum potential energy well has been suggested. The results indicate that (σ11–σiso) decreases and (σ33–σiso) increases for the deuteriated complex with respect to the undeuteriated adduct. This fact is consistent with the hypothesis of a single-minimum potential energy surface for the short hydrogen bond.