Synthesis and characterization of the first Te(IV) organometallic complexes with azepane-1-carbodithioate

GRAPHICAL ABSTRACT

ABSTRACT

We report the synthesis and spectroscopic characterization of organometallic Te(IV) complexes bearing the seven-membered azepane-1-carbodithioate ligand and four different types of tellurium(IV) heterocycles; [C₄H₈Te{S₂C-N(CH₂)₆}₂](2),[C₈H₈Te{S₂C-N(CH₂)₆}₂](3),[C₄H₈OTe{S₂C-N(CH₂)₆}₂](4)and [C₅H₁₀Te{S₂C-N(CH₂)₆}₂](5). Compounds 2–5, obtained in a 2:1 stoichiometric ratio, are air-stable for long periods of time, but readily decompose in solution. They have been characterized by elemental analyses, IR, FAB⁺–MS, and multinuclear NMR (¹H, ¹³C, and ¹²⁵Te) spectroscopy. The molecular structures of 2 and 5 were established by single-crystal X-ray diffraction studies. The geometrical arrangement around the tellurium atom can be described as a distorted trigonalbipyramid or sawhorse structure, typical for tellurium atom, where the lone pair is apparently stereochemically active, occupying an equatorial position. The coordination mode for the azepane-1-carbodithioate ligands is considered as anisobidentate. Due to the orthogonal arrangement of the dithiocarbamate groups around tellurium, it is difficult for other atoms to approach and in consequence there are not intermolecular secondary interactions.

KEYWORDS:

• Dithiocarbamates
• azepane-1-carbodithioate
• tellurocycles
• tellurium (IV)

Acknowledgments

The spectroscopic analyses (EI-MS and multinuclear ¹H, ¹³C, and ¹²⁵Te NMR) were performed at the Centro de Investigaciones Químicas, UAEM. The authors are grateful to the staff for this service.