Conformational isomerism of the binuclear N,N-pentamethylenedithiocarbamate cadmium(II) complex, [Cd-2{S2CN(CH2)(5)}(4)] on multinuclear (N-15, Cd-113) CP/MAS NMR and single-crystal X-ray diffraction data

摘要

Crystalline N,N-cyclo-pentamethylenedithiocarbamate (PmDtc) cadmium(II) complex was prepared and studied by means of N-15, Cd-113 CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. The unit cell of the cadmium(II) compound comprises two centrosymmetric isomeric binuclear molecules [Cd-2{S2CN(CH2)(5)}(4)], which display structural inequivalence in both N-15 and Cd-113 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 Cd-113 chemical shift tensors. All experimental N-15 resonance lines were assigned to the nitrogen structural sites in both isomeric binuclear molecules. (c) 2006 Elsevier B.V. All rights reserved.