Conformational isomerism of the binuclear N,N-pentamethylenedithiocarbamate cadmium(II) complex, [Cd2{S2CN(CH2)5}4] on multinuclear (N, Cd) CP/MAS NMR and single-crystal X-ray diffraction data

Crystalline N,N-cyclo-pentamethylenedithiocarbamate (PmDtc) cadmium(II) complex was prepared and studied by means of ¹⁵N, ¹¹³Cd CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. The unit cell of the cadmium(II) compound comprises two centrosymmetric isomeric binuclear molecules [Cd₂{S₂CN(CH₂)₅}₄], which display structural inequivalence in both ¹⁵N and ¹¹³Cd NMR and XRD data. There are pairs of the dithiocarbamate ligands exhibiting different structural functions in both isomeric molecules. Each of the terminal ligands is bidentately coordinated to the cadmium atom and forms a planar four-membered chelate ring [CdS₂C]; whereas pairs of the tridentate bridging ligands combine two neighbouring cadmium atoms forming an extended eight-membered tricyclic moieties [Cd₂S₄C₂], whose geometry can be approximated by a ‘chair’ conformation. The structural states of cadmium atoms were characterised by almost axially symmetric ¹¹³Cd chemical shift tensors. All experimental ¹⁵N resonance lines were assigned to the nitrogen structural sites in both isomeric binuclear molecules.