Synthesis and structure of an arylselenenium (II) cation, [C34H41N4Se+](2)[Hg([SeCN)(4)](2-), based on a 5-tert-butyl-1,3-bis([1-pentyl-1H-benzimidazol-2-yl)benzene scaffold

In the title salt, bis{[5-tert-butyl-1,3-bis(1-pentyl-1H-benzimidazol-2-yl)benzene]selenium} tetrakis(selenocyanato) mercury, (C34H41N4Se)(2)[Hg(SeCN)(4)], the arylselenenium cations, [C34H41N4Se](+), are linked through [Hg(SeCN)(4)](2-) anions by C-H center dot center dot center dot N hydrogen bonds. In the cation, the geometry around the Se atom in the 5-tert-butyl-1,3-bis(1-pentyl-1H-benzimidazol-2-yl)benzene scaffold is T-shaped, resulting from the coordination of Se by the C atom of the central aromatic ring and the N atoms of both of the benzimidazole moieties. The trans Se-N bond lengths are almost equal [2.087 (3) and 2.099 (3) angstrom] and the Se-C bond length is 1.886 (3) angstrom. The N-Se-N angle is 159.29 (11)degrees. The geometry around the Hg II atom in the [Hg(SeCN)(4)](2-) anion is distorted tetrahedral, with Se-Hg-Se angles ranging from 88.78 (3) to 126.64 (2)degrees. In [Hg(SeCN)(4)](2-), the Hg-Se bonds are unsymmetrical [2.5972 (4) and 2.7242 (5) angstrom]. One of the pentyl substituents is disordered over two equivalent conformations, with occupancies of 0.852 (8) and 0.148 (8).