On the palladium(II) complexes of tetramethyldithiooxamide and tetraethyldithiooxamide

Abstract

With Pd(II) in acid media tetramethyldithiooxamide (Met4D) and tetraethyldithiooxamide (Et4D) form diamagnetic, 1:2 electrolyte complexes PdL2(ClO4)2 and non-electrolyte complexes PdLX2 (X  Cl, Br, I). I.R. spectra, recorded in the range of 4000-250 and 400-60 cm−1, indicate for the perchlorate complexes a square-planar sulphur coordination and for the halide complexes a cis-planar symmetry. Electronic spectra, recorded both in Nujol mulls and in solution, show only one band, in the range 17,000–18,700 cm−1, which are d-d in character. The band at 18,700 cm−1 for the perchlorates may be assigned, on the basis of a D2h symmetry, to the 1Ag → 1B1g transition. The value obtained for the splitting parameter Δ1 (20,800 cm−1) indicate that these ligands assume an intermediate position in the spectrochemical series proposed for the Pd(II) planar complexes.