Synthesis of some new transition metal complexes derived from tellurated formazanes

A novel series of organotellurium compounds based on formazane derivatives with a general formula of ArTeBr₃ 4 and Ar₂TeBr₂ 5 [Ar = 2-[{4-hydroxy-3-methoxyphenyl}{4-nitrophenyldiazenyl}methylene amino]-5-nitrophenyl] were synthesized by refluxing mercurated formazane derivative ArHgCl with TeBr₄ in two different mole ratios of 1:1 and 2:1, respectively, in dry dioxane solvent under an argon atmosphere. Compounds ArTeBr₃ and Ar₂TeBr₂ were then reduced by the action of an ethanolic solution of hydrazine hydrate to obtain Ar₂Te₂ 6 and Ar₂Te 7, respectively. The ligand properties of bis(2-[{4-hydroxy-3-methoxy phenyl}{4-nitrophenyl diazenyl}methylene amino]-5-nitrophenyl) telluride (7) were examined toward several metal ions through its reaction with K₂PtCl₄, PdCl₂ · 2 H₂O, K₂PtCl₆, RhCl₃ · 3 H₂O, CoCl₃ · 6 H₂O and NiCl₂, respectively. These compounds were characterized by FTIR, UV-Vis,¹H and ¹³C{¹H} NMR spectroscopy and mass spectrometry as well as by elemental analysis, thermal analysis, magnetic susceptibility and molar conductivity. The identification of the synthesized complexes 8-13 proved that the complexes of Pt(II), Pd(II) and Ni(II) have square pyramidal geometries and are diamagnetic, while the complexes of Pt(IV), Rh(III) and Co(III) have octahedral shapes with the same magnetic behavior. The telluride 7 behaves as a neutral pentadentate ligand.