Conformational isomerism of the binuclear N,N-pentamethylenedithiocarbamate cadmium(II) complex, [Cd2{S2CN(CH2)5}4] on multinuclear (15N, 113Cd) 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.

Graphical abstractN,N-cyclo-pentamethylenedithiocarbamate cadmium(II) complex was prepared and studied by (15N, 113Cd) CP/MAS NMR and single-crystal X-ray diffraction. The unit cell of the prepared compound comprises two centrosymmetric isomeric binuclear molecules [Cd2{S2CN(CH2)5}4], in which pairs of dithiocarbamate ligands display different structural functions (i.e., terminal chelating and tridentate bridging). To characterise the structural state of the cadmium atoms, 113Cd chemical shift anisotropy parameters (δaniso and η) were calculated from spinning sideband manifolds in MAS NMR spectra. All 15N resonance lines were assigned to the nitrogen structural sites in both isomeric molecules.Figure optionsDownload full-size imageDownload as PowerPoint slide