Vibrational and NMR spectra and structures of lithium pyruvate monohydrate

The IR, Raman, and 13C NMR spectra of lithium pyruvate monohydrate and its isotopic compounds including the O-deuterated and 18O- and 13C- analogs have been measured in the solid state. The IR and NMR spectra of aqueous solutions of the lithium, sodium, and potassium salts have also been obtained for comparison. No CO stretching band is observed in the solid state IR and Raman spectra, and the spectral changes on O-deuteration and 2-13C- and 18O-labellings cannot be explained in terms of ordinary crystal water. In the solid state 13C NMR a characteristic peak is observed at δ 94.9 in place of a carbonyl carbon peak expected around δ 200. These findings confirm that the lithium salt hydrate has the gem-diol structure in the solid state.