Synthesis and Structural Features of a New Diselenonium Dication Stabilized by Sulfur Atoms of Thiourea Groups: X-ray Characterization of [(Se-ettu)2]Br2 (ettu = ethylenethiourea)

Selenium and bromine were refluxed in methanol and stirred with ethylenethiourea to give yellow crystals of [(Se-ettu)2]Br2 (ettu = ethylenethiourea). The first reported 1,2-diselenonium dication stabilized by sulfur atoms is air unstable and yields a three-dimensional lattice with Se+···Br−···Se+ bridges enclosing also single Se+···Br− interactions and H···Br− bonds. The air instability of [(Se-ettu)2]Br2 probably is due to redox reactions which lead to the decomposition of ethylenethiourea with precipitation of sulfur.