Crystallographic studies of dihalogeno-tetramethylethylenediamine complexes of zinc, cadmium, and mercury. II: Crystal and molecular structure of dibromo-(N,N,N′,N′-tetramethylethylenediamine) cadmium(II)

Abstract

The crystal structure of dibromo-(N,N,N′N′-tetramethylethylenediamine) cadmium(II), C₆H₁₆Br₂CdN₂, has been determined from 1890 reflections measured on a Siemens four-circle diffractometer using the ω/2θ scan technique and CuKα. radiation. The crystals are monoclinic:P2₁/c,a = 7.532(2),b = 10.689(6),c = 14.674(7) Å, β = 91.91(7) β andZ = 4. The structure was solved by Fourier methods and refined by full-matrix least squares to a finalR (conventional) of 6.1%. Anisotropic thermal parameters were evaluated for the non-hydrogen atoms, but the hydrogen atoms were assigned the average isotropic thermal parameter of the carbon atoms. Each cadmium atom is octahedrally coordinated by two pairs of bromine atoms, giving average Cd-Br bond lengths of 2.753(2) and 2.844(2) Å, and a pair of nitrogen atoms in thecis configuration with respect to cadmium, with an average Cd-N bond length of 2.46(1) Å. The average Br-Cd-Br and N-Cd-Br angles are 88.1 and 90.6 ° respectively. The bromine atoms provide bridges to the metal atoms, resulting in a chain-like structure with the chain direction approximately parallel to thex-axis.