(Tris{2-[2-(2,3,5,6-tetrafluoro-4-iodophenoxy)ethoxy]ethyl}amine)potassium iodide

The title adduct, [K(C30H24F12I3NO6)]I, gives an extended tape of cations linked through I⋯I− halogen bonds (XBs), two of them being quite short and one quite long. In the structure, the cation is hosted in a cavity formed by the arms of the podand which presents a closed conformation wherein two tetrafluoroiodobenzene rings are near parallel [dihedral angle = 15.8 (4)°; centroid–centroid distance = 3.908 (5) Å] and the third ring is closer to orthogonal [dihedral angles = 66.28 (14) and 75.20 (19)°] to the other two rings. The coordination sphere of the K+ cation is composed of the six O atoms, the N atom and an F atom in the ortho position of one of the rings.

The title adduct, [K(C 30 H 24 F 12 I 3 NO 6 )]I, gives an extended tape of cations linked through IÁ Á ÁI À halogen bonds (XBs), two of them being quite short and one quite long. In the structure, the cation is hosted in a cavity formed by the arms of the podand which presents a closed conformation wherein two tetrafluoroiodobenzene rings are near parallel [dihedral angle = 15.8 (4) ; centroid-centroid distance = 3.908 (5) Å ] and the third ring is closer to orthogonal [dihedral angles = 66.28 (14) and 75.20 (19) ] to the other two rings. The coordination sphere of the K + cation is composed of the six O atoms, the N atom and an F atom in the ortho position of one of the rings.
GC, PM, GR and GT acknowledge Fondazione Cariplo (projects 2009-2550and 2010-1351 for financial support. such as HI, Abate et al.,(2009). Here the supramolecular cations ( Fig. 1) formed by potassium coordination are linked by two short (namely strong) and one long (namely week) C-I···I -XBs (see Table A) and unlimited tapes are formed. A similar interactions pattern is observed in the isomorphous NaI adduct. In both structures the cation is hosted in a cavity formed by the podand's arms which presents a closed conformation wherein two tetrafluoroiodobenzene rings strictly parallel and the third ring nearly orthogonal. In this system the three C-I bonds are only slightly divergent from each other. The small Na + cation is much more masked than the larger K + one (see Fig. 2). Table B reports some characteristic of the cavity and evidences the differences between the K + and Na + coordination. Figure 3 shows two projections of the salt tapes. The ditopic receptor/HI adduct presents a completely different pattern of interactions. The podand molecules and iodide anions work as bidentate XB donors and acceptors, respectively. The H + is simply bound to the N atom, the supercation adopts conformation different from adopted on K + and Na + coordination as the three tetrafluoroiodobenzene rings are completely divergent.

Experimental
The chemical synthesis of the neutral triamine compound was carried on following the procedure reported in Mele et al., (2005). Good crystals were obtained from a CHCl 3 solution of the KI complex after slow solvent diffusion in a box containing vaseline oil.

Refinement
Hydrogen atoms were constrained with C-H = 0.97 Å and with U iso (H) = 1.2 times U eq (C).

(Tris{2-[2-(2,3,5,6-tetrafluoro-4-iodophenoxy)ethoxy]ethyl}amine)potassium iodide
where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 2.37 e Å −3 Δρ min = −1.25 e Å −3 Special details Experimental. The sample gave two kinds of crystals: rhombic tablets were suitable for data collection, elongated prisms were always twinned of the first. An attempt to collect data at lower temperature failed, probably due to a phase transition or the crystal cracking. Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.   (7) 179.21 (18) Symmetry codes: (i) -x, -y, -z; (ii) -x, -y, -z+1.  (17) In the NaI adduct, Na + ···F4 and Na + ···O6 distances cannot be considered as bond lengths, thus they are only reported for sake of comparison.