Vibrational and NMR spectra and structures of lithium pyruvate monohydrate

Abstract

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 C O 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.