cis-Bis(2,2 '-bipyridyl-N,N,N ')dichlorosilicon diiodide

The crystal and molecular structure of the title compound, C20H16Cl2N4Si2+. 2I(-), has been determined at 173 K. To our knowledge, this is the first c rystal structure of a silicon tetrahalide complex with a bidentate base as a ligand. The two chloro ligands are cis relative to each other. The Si-N b onds trans to a chloro ligand are longer than the Si-N bonds trans to an Si -N bond. This feature is observed for the majority of M(bipy)(2)Cl-2 (M = m etal and bipy = 2,2'-bipyridyl) complexes, but it does not hold for all str uctures retrieved from the Cambridge Structural Database. The two pyridyl r ings of each bipyridyl unit are nearly coplanar, whereas the bipyridyl unit s are almost perpendicular to each other. The two I- ions are more than 5 A ngstrom from the silicon centre. As a result, the compound can definitely b e described as ionic. The crystal packing is stabilized by short C-H ... I contacts.