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

Gabriella Cavallo; Hannes Neukirch; Pierangelo Metrangolo; Tullio Pilati; Giuseppe Resnati; Giancarlo Terraneo

doi:10.1107/S1600536813010532

. 2013 Apr 24;69(Pt 5):m284–m285. doi: 10.1107/S1600536813010532

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

Gabriella Cavallo ^a, Hannes Neukirch ^a, Pierangelo Metrangolo ^a, Tullio Pilati ^a, Giuseppe Resnati ^a, Giancarlo Terraneo ^a,^*

PMCID: PMC3647819 PMID: 23723785

Abstract

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.

Related literature

For the synthesis of tris{2-[2-(2,3,5,6-tetrafluoro-4-iodophenoxy)ethoxy]ethyl}amine and its NaI adduct, see: Mele et al. (2005 ▶). For its HI salt, see: Abate et al. (2009 ▶). graphic file with name e-69-0m284-scheme1.jpg

Experimental

Crystal data

[K(C₃₀H₂₄F₁₂I₃NO₆)]I
M _r = 1269.20
Monoclinic,
a = 13.037 (2) Å
b = 23.355 (3) Å
c = 13.787 (2) Å
β = 104.83 (3)°
V = 4058.0 (11) Å³
Z = 4
Mo Kα radiation
μ = 3.27 mm⁻¹
T = 295 K
0.34 × 0.22 × 0.10 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.759, T _max = 1.000
24956 measured reflections
7254 independent reflections
5627 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.119
S = 1.06
7254 reflections
487 parameters
H-atom parameters constrained
Δρ_max = 2.37 e Å⁻³
Δρ_min = −1.25 e Å⁻³

Data collection: APEX2 (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 1998 ▶); data reduction: SAINT; program(s) used to solve structure: SIR2002 (Burla et al., 2003 ▶); program(s) used to refine structure: SHELXL2012 (Sheldrick, 2012 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXL2012.

Supplementary Material

Click here for additional data file.^{(37.9KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813010532/pk2473sup1.cif

e-69-0m284-sup1.cif^{(37.9KB, cif)}

Click here for additional data file.^{(397.5KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813010532/pk2473Isup2.hkl

e-69-0m284-Isup2.hkl^{(397.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. I⋯I⁻ XBs and short F⋯F contacts (Å and °).

C—X⋯Y	X⋯Y	C—X⋯Y
C8—I1⋯I4	3.4106 (6)	179.30 (13)
C8—I2⋯I4ⁱ	3.4157 (6)	168.45 (13)
C8—I3⋯I4ⁱⁱ	3.9437 (7)	179.21 (18)

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Symmetry codes: (i) −x, −y, −z; (ii) −x, −y, −z + 1.Note: for the sake of comparison, a Cambridge Structural Database (Allen, 2002 ▶) search for C—I⋯I⁻ contacts gives 109 hits with a mean I⋯I⁻ distance of 3.53 (3) Å, the lower and higher quartiles being 3.43 and 3.63 Å, respectively.

Table 2. Short contacts in receptor–metal cation system for KI and NaI adducts.

	K⁺	Na⁺
N1	2.903 (4)	2.515 (15)
O1	2.744 (3)	2.388 (12)
O2	2.849 (3)	2.716 (12)
O3	2.707 (4)	2.463 (13)
O4	2.809 (4)	2.424 (12)
O5	2.756 (4)	2.371 (14)
O6	2.911 (4)	4.39 (2)
F4	3.041 (4)	3.124 (17)

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Note: in the NaI adduct, Na⁺⋯F4 and Na⁺⋯O6 distances cannot be considered as bond lengths, thus they are only reported for the sake of comparison.

Acknowledgments

GC, PM, GR and GT acknowledge Fondazione Cariplo (projects 2009–2550 and 2010–1351) for financial support.

supplementary crystallographic information

Comment

Tris(2-(2-(2,3,5,6-tetrafluoro-4-iodophenoxy)ethoxy)ethyl)amine has been systhesized as neutral ditopic receptor for alkali metal halide such as NaI, Mele et al.,(2005). It has been also employed as receptor for hydrogen halide systems 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 CHCl₃ solution of the KI complex after slow solvent diffusion in a box containing vaseline oil.