Structural study of four complexes of the M-N2S2 type derived from diethylphenylazothioformamide and the metals palladium, platinum, copper and nickel

Abstract

The four electron-transfer complexes trans-(di(N,N-diethyl-(2-phenyldiazenyl)thioformamide-κS,κN 2))nickel, trans-(di(N,N-diethyl-(2-phenyldiazenyl)thioformamide-κS,κN 2))copper, trans-(di(N,N-diethyl-(2-phenyldiazenyl)thioformamide-κS,κN 2))palladium and trans-(di(N,N-diethyl-(2-phenyldiazenyl)thioformamide-κS,κN 2))platinum have been crystallized, and their structures have been determined at low temperature. All the complexes are of the M-N2S2 type. The crystals of both the nickel and the copper complex belong to the tetragonal P41212 system, in which the central metal ion lies on a twofold axis. The tetrahedral molecular symmetry around the central metal ion is unusual for the M-N2S2 electron-transfer complexes. The crystals of the palladium and platinum complexes on the other hand belong to the monoclinic C2/c system in which the metal ion lies on an inversion centre. The molecular symmetry around these metal ions is square planar. It is demonstrated that the π electron density in the ligand planes has a high degree of delocalization. Furthermore, unusually large line broadening of the 1H NMR spectra was observed and investigated as a function of temperature for the palladium complex.