Spectroscopic and thermochemical investigation of alkaline earth metal salts of 2-oximinopropionate

Alkaline earth metal 2-oximinopropionates were prepared by the reaction of sodium 2-oximinopropionate with the respective metal nitrates or chlorides in water at room temperature. These compounds were characterized by infrared and multinuclear NMR spectroscopy and thermogravimetric analysis. The thermal decomposition of the salts occurs in the range 144-188°C and exhibits a trend towards lower temperature with increasing size of the cation. In all cases, the decomposition yields a metal carbonate. The molecular structure of calcium 2-oximinopropionate hydrate was determined by single-crystal X-ray crystallography. Crystal data: C6H10N2O7Ca, MW = 262.24 g/mol, triclinic, space group P͞1 (No.2), a = 8.954(1) Å, b = 9.3851(7) Å, c = 6.2445(7) Å, α = 97.209(8)°, β = 104.917(9)°, γ = 87.250(8)°, V = 503.0(2) Å3, Z = 2, Dcalc = 1.73 g cm–3, R = 0.03 and Rw = 0.04. Key words: crystal structure, alkaline earth, 2-oximinopropionate, thermal decomposition.