Nickel(II) and palladium(II) chelates of dehydroacetic acid Schiff bases derived from thiosemicarbazide and hydrazinecarbodithioate

Abstract

Dehydroacetic acid Schiff bases DAE (1) and DATS (2) were isolated from the reaction of dehydroacetic acid (2-acetyl-5-hydroxy-3-oxo-4-hexenoic acid-δ-lactone) with hydrazine-S-methylcarbodithioate and the corresponding acid amide, thiosemicarbazide, respectively. Reaction of such Schiff bases with nickel(II) and palladium(II) ions afforded the dimeric monoligand chelates [M(DAE-2H)]2 and [M(DATS-2H)]2; M = Ni(II) or Pd(II). In the presence of monodentate Lewis bases, B, square-planar chelates [M(DAE-2H)B] and [M(DATS-2H)B], in which B = pyridine or triphenylphosphine, were isolated. The stoichiometry and structure of the isolated organic ligands and their chelates were confirmed through elemental analyses, molecular weight determination, and infrared, ultraviolet–visible, and 1H and 13C nuclear magnetic resonance spectroscopy.