Cobalt(III) complexes of neutral selenium and tellurium donor ligands: synthesis and nuclear magnetic resonance studies

Abstract

The first examples of diseleno- and ditelluro-ether complexes of cobalt(III), [Co(MeSeCH₂CH₂SeMe)₂X₂]BPh₄(X = Cl, Br, or I) and [Co{o-C₆H₄(TeMe)₂}₂X₂]BPh₄(X = Br or I), have been prepared by air oxidation of mixtures of anhydrous CoX₂, ligand, and NaBPh₄ in nitromethane. The complexes have been characterised by u.v.–visible and multinuclear n.m.r. (⁵⁹Co, ⁷⁷Se-{¹H}, and ¹²⁵Te-{¹H}) spectroscopy. The iodo complexes are trans isomers, but both cis and trans forms are present with the other halides.