(4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane)sodium iodide–1,1,2,2,tetrafluoro-1,2-diiodoethane (2/3)

The title complex (CX1), [Na(C18H36N2O6)]I·1.5C2F4I2, is a three-component adduct containing a [2.2.2]-cryptand, sodium iodide and 1,1,2,2-tetrafluoro-1,2-diiodoethane. The diiodoethane works as a bidentate halogen-bonding (XB) donor, the [2.2.2]-cryptand chelates the sodium cation, and the iodide counter-ion acts as a tridentate XB acceptor. A (6,3) network is formed in which iodide anions are the nodes and halocarbons the sides. The network symmetry is C 3i and the I...I- XB distance is 3.4492 (5) Å. This network is strongly deformed and wrinkled. It forms a layer 9.6686 (18) Å high and the inter-layer distance is 4.4889 (10) Å. The cations, interacting with each other via weak O...H hydrogen bonds, are confined between two anionic layers and also form a (6,3) net. The structure of CX1 is closely related to that of the KI homologue (CX2). The 1,1,2,2,-tetrafluoro-1,2- diiodoethane molecule is rotationally disordered around the I...I axis, resulting in an 1:1 disorder of the C2F4 moiety.