Cobalt(III) dimethylglyoximates containing selenourea and an unusual diselenourea ligand: Synthesis and structures

Abstract

The complexes [Co(DH)2(Seu)y(Se-Seu)z]2X · mSolv (DH is the dimethylglyoxime monoanion, Seu is selenourea, and X is [TiF6]2−, [ZrF6]2−) were obtained from the system CoX · 6H2O-DH2-Seu in DMF-MeOH or MeOH-H2O and examined by UV, IR, and NMR spectroscopy and X-ray diffraction. Unexpectedly, the ligand Se-Seu (the oxidized form of selenourea) was detected on the axial coordinate, partially replacing selenourea. The complexes were formulated as [Co(DH)2(Seu)1.75(Se-Seu)0.25]2[TiF6] · H2O (I) and [Co(DH)2(Seu)(Se-Seu)]2[ZrF6] · 3H2O (II). The complex cations in I and II have trans-octahedral structures. Their crystal structures are made up of the complex Co3+ cations and the outer-sphere MF62− anions (M = Ti(IV) (I) and Zr(IV) (II)) held together by electrostatic interactions and hydrogen bonds; water of crystallization is also involved in hydrogen bonding.