Synthesis and characterization of monomeric tellurolato complexes of zinc and cadmium: crystal and molecular structure of bis[2-(4,4-dimethyl-2-oxazolinyl)phenyl]ditelluride

Abstract

The synthesis and characterization of homoleptic zinc(II) and cadmium(II) tellurolates incorporating the intramolecularly chelating oxazoline ligand are described. The derivatives, M[Te(Ox)]₂ [M=Zn (4) or Cd (5) and Ox=2-(4,4-dimethyl-2-oxazolinyl)phenyl], are prepared in good yield via the metathesis reactions of MCl₂ with lithium arenetellurolate, OxTe⁻Li⁺ (2). Attempts to synthesise the mercury complex led to isolation of the corresponding ditelluride (3). Crystal structure of the ditelluride was determined by X-ray diffraction method. Of particular interest in the structure is the intramolecular interaction of the sp² nitrogen with the tellurium. The strength of the Te...N nonbonded interactions in this compound [Te(1)...N(1): 2.864(5), Te(2)...N(2): 2.694(5) Å] is found to be stronger than the similar interactions found in related compounds. The zinc and cadmium complexes are quite stable in the solid state and highly soluble in common non-polar organic solvents. The variable temperature NMR spectra of Zn[Te(Ox)]₂ (4) and Cd[Te(Ox)]₂ (5) show the complexes to be chiral at low temperatures.