Abstract
Equimolar quantities of tetraethylammonium chloride (Et4NCl) and 3,4,5,6-tetrafluoro-1,2-diiodobenzene (o-DITFB or o-C6F4I2) have been co-crystallized in a solution of dichloromethane yielding a pure halogen-bonded compound, 3,4,5,6-tetrafluoro-1,2-diiodobenzene-tetraethyl ammonium chloride (2/1), Et4N+center dot Cl-center dot 2C(6)F(4)I(2), in the form of translucent needles. [(Et4NCl)(o-C6F4I2)(2)] packs in the C2/c space group. The asymmetric unit includes one molecule of DITFB, one Et4N+ cation located on a twofold rotation axis, and one chloride anion also located on a twofold rotation symmetry axis. This compound has an interesting halogen-bonding environment surrounding the halide. Here, the chloride anion acts as a tetradentate halogen bond acceptor and forms a distorted square-pyramidal geometry, with I center dot center dot center dot Cl-center dot center dot center dot I angles of 80.891 (6) and 78.811 (11)degrees, where two crystallographically distinct iodine atoms form halogen bonds with the chloride anion. Resulting from that square-pyramidal geometry are short contacts between some of the adjacent F atoms. Along the b axis, the halogen-bonding interaction results in a polymeric network, producing a sheet in which the two closest chloride ions are 7.8931 (6) angstrom apart. The Et4N+ cation alternates in columns with the halide ion. The expected short contacts (shorter than the sum of their van der Waals radii) are observed for the halogen bonds [3.2191 (2) and 3.2968 (2) angstrom], as well as almost linear angles [170.953 (6) and 173.529 (6)degrees].