Structure and properties of mono- and heterometallic cadmium, zinc, and nickel complexes containing diethyldithiocarbamate ions and ethylenediamine molecules

Abstract

The crystal structure of the mono- and heterometallic complexes [MEn₃]L₂ (M = Zn²⁺,M²⁺) and [MEn₃ ][CdL₃]₂ (M = Cd²⁺, Zn²⁺, Ni₂₊) containing ethylenediamine (En) molecules and diethyldithio-carbamate ions (L = (C₂H₅)₂NCS ⁻₂ ) is investigated. The three heterometallic complexes are isostructural; their structure consists of discrete mononuclear ions. In the [MEn₃]²⁺ cation, the central M atom lies on the twofold axis; therefore, two of the three metallocycles MN₂C₂ of the [MEn₃]²⁺ cation are independent. One of the two has a gosh-configuration. In the coordinated En molecules, the N-M-N chelate angles are 77.0 and 82.9‡ (M = Cd₂₊); 80.0 and 80.5‡ (M = Zn²⁺); 79.7 and 80.8‡ (M = Ni²⁺). The nitrogen atoms form a distorted octahedron around M. The average M-N bond lengths for the complexes are 2.35, 2.19, and 2.16 å for M = Cd²⁺, Zn²⁺, and Ni²⁺, respectively. All the atoms of the [CdL₃]⁻ complex anion are in the general position; the central atom coordinates three cyclic bidentate L⁻ ligands. The S atoms form a distorted trigonal prism, where the S...S distances in the vertical edges are nearly the same in all the complexes (2.94(1)-3.00(2) å). It was shown by¹H,¹⁴N, and¹¹³Cd NMR that the ionic complexes [ZnEn₃]L₂ and [CdEn₃][CdL₃]₂ in solution are transformed into nonelectrolyte type mixed-ligand complexes.