Diorganyl dichalcogenides with intramolecular coordination interactions: the synthesis and structure of bis(4,6-dimethylpyrimidin-2-yl) diselenide

Bis(4,6-dimethylpyrimidin-2-yl) diselenide, a new representative of dihetaryl diselenides, was obtained by successively treating selenourea with hydrochloric acid, acetylacetone, potassium hydroxide, and the system iodine—potassium iodide. The unusual planar trans-conformation of this compound (X-ray diffraction data) is stabilized by intramolecular attractive nonvalent Se…N interactions (Se…N, 2.926(1) A) and stacking of the π-systems of the aromatic heterocycles (the centers of the pyrimidine rings are spaced apart at 3.365(2) A). The energy parameters of the factors that make the molecular structure flattened were estimated by quantum chemical DFT calculations.