Synthesis of 3-butanoyl- and 3-benzoyl-4-hydroxy-3-pyrrolin-2-ones and their complexes with metal ions

Abstract The new α-acyl-tetramic acids, 3-butanoyl- and 3-benzoyl-4-hydroxy-3-pyrrolin-2-ones have been synthesized and their complexes with Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) prepared. The magnetic and spectroscopic properties of the Co(II), Ni(II), and Cu(II) halide and thiocyanate complexes of formula MX 2 L (L = tetramic acid ligand) indicate that these contain six-coordinated metals with both bridging anions and tetramic acids. The acids appear to be bonded to the metals through the nitrogen atom and a carbonyl oxygen atom. The i.r. spectra indicate the Cd(II) and Hg(II) complexes to be tetrahedral. A few complexes of formula MX 2 L 2 (M = Co, Cu) have been prepared; these also contain six-coordinated metals.