catena-Poly[[bis­(μ2-1,4,7,10,13,16-hexa­oxacyclo­octa­deca­ne)dipotassium]-μ2-iodido-(iodidocadmium)-di-μ2-iodido-(iodidocadmium)-μ2-iodido]

Rajarajan, K.; Pugazhenthi, A.; NizamMohideen, M.

doi:10.1107/S1600536813002274

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 69| Part 2| February 2013| Page m125

doi:10.1107/S1600536813002274

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catena-Poly[[bis(μ₂-1,4,7,10,13,16-hexaoxacyclooctadecane)dipotassium]-μ₂-iodido-(iodidocadmium)-di-μ₂-iodido-(iodidocadmium)-μ₂-iodido]

K. Rajarajan,^a ^* A. Pugazhenthi ^b and M. NizamMohideen ^c ^*

^aDepartment of Physics, Rajeswari Vedachalam Government Arts College, Chengalpet 603 001, India, ^bResearch and Development Centre, Bharathiyar University, Coimbatore 641 046, India, and ^cDepartment of Physics, The New College (Autonomous), Chennai 600 014, India
^*Correspondence e-mail: drkrr2007@gmail.com, mnizam_new@yahoo.in

(Received 12 January 2013; accepted 23 January 2013; online 31 January 2013)

The reaction of CdCl₂, 18-crown-6 and KI in water yields the title coordination polymer, [{K(C₁₂H₂₄O₆)}₂Cd₂I₆]_n. The potassium ion lies approximately in the plane of the crown ether, coordinated by all six crown ether O atoms and also by an iodide anion bound to a cadmium atom. A C atom of the crown ether is disordered over two positions with site occupancies of 0.77 (2) and 0.23 (2). Two K(18-crown-6)⁺ units are linked by inversion symmetry, forming a [bis(μ₂-18-crown-6)dipottasium] system with approximately square-planar K₂O₂ units. Inversion symmetry also generates the Cd₂I₆ fragment and the polymeric system is extended along the c axis by the formation of K—I—Cd bridges.

Related literature

For applications of polyiodides, see: Yang et al. (2011 ). For the properties of cadmium compounds, see: Ramesh et al. (2012 ). For related structures, see: Park et al. (2010 ); Guo et al. (2006 ); Kunz et al. (2009 ).

Experimental

Crystal data

[Cd₂K₂I₆(C₁₂H₂₄O₆)₂]
M_r = 796.51
Monoclinic, P 2₁ /c
a = 10.627 (2) Å
b = 14.986 (2) Å
c = 15.190 (3) Å
β = 103.959 (1)°
V = 2347.7 (7) Å³
Z = 4
Mo Kα radiation
μ = 5.07 mm⁻¹
T = 293 K
0.20 × 0.15 × 0.10 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ) T_min = 0.430, T_max = 0.631
21969 measured reflections
4129 independent reflections
3585 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.028
wR(F²) = 0.067
S = 1.03
4129 reflections
219 parameters
6 restraints
H-atom parameters constrained
Δρ_max = 1.53 e Å⁻³
Δρ_min = −1.16 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT and XPREP (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ) and Mercury (Macrae et al., 2008 ); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536813002274/sj5295sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813002274/sj5295Isup2.hkl

checkCIF report

Comment top

There is a general interest in polyiodides as they are well known for having a significant influence on the redox chemistry in dye-sensitized solar cells (Yang et al., 2011).

In a recent paper, we reported the synthesis and crystal structure of catena-Poly[ammonium (cadmium-tri-lthiocyanato- κ⁴S:N;κ²N:S)-1,4,10,13,16- hexaoxacyclooctadecane (1/1)] (Ramesh et al., 2012). As part of our ongoing investigation of Cd and 18-crown-6 derivatives, we report here the synthesis and structure of the title compound.

The reaction of CdCl₂ with 18-crown-6 and KI in de-ionized water yields the title coordination polymer [{K(C₁₂H₂₄O₆)}₂Cd₂I₆]_n (Fig.1). The carbon atom (C2) of the crown ether is disordered, as detectable from the large displacement parameters for the C atom and short C-O bond lengths. The disorder over two positions was modelled and the site occupancies refined to 0.77 (2) and 0.23 (2). The geometry was regularized by soft restraints.

The potassium ion lies close to the plane of the crown ether deviating by 0.1257 (2)Å from the mean plane of the six crown ether oxygen atoms (Kunz et al., 2009). The K-O (K1, O1-O6) distances range from 2.686 (4) to 3.011 (4)Å and compare well to those of similar complexes (Kunz et al., 2009). K1 is coordinated by all six oxygen atoms of the crown ether and also by the I3 iodide anion bound to the Cd(II) cation forming a K1—I3—Cd1 bridge. The mean Cd-I (Cd1, I1-I3) bond lengths [2.764 (2)Å] and angles around the Cd1 atom range from 95.0 (2)° to 115.5 (2)° and are similar to those reported for comparable complexes (Park et al., 2010; Guo et al., 2006).

Fig. 2. shows a view of the crystal structure down the a axis. The title compound is stabilized by van der Waals forces only, and no classical intra- or intermolecular hydrogen bonds are found.

Related literature top

For applications of polyiodides, see: Yang et al. (2011). For the properties of cadmium compounds, see: Ramesh et al. (2012). For related structures, see: Park et al. (2010); Guo et al. (2006); Kunz et al. (2009).

Experimental top

A mixture of 18-crown-6 (C₁₂H₂₄O₆), CdCl₂ and KI (molar ratio 1:1:3) was thoroughly dissolved in de-ionized water and stirred for 4 h to obtain a homogeneous mixture. Colorless single crystals were obtained after the filtrate had been allowed to stand at room temperature for two weeks.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT and XPREP (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Figures top

	Fig. 1. View of the title compound showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% probability level. H atoms are presented as a small spheres of arbitrary radius.
	Fig. 2. Molecular packing viewed along the a axis.

catena-Poly[[bis(µ₂-1,4,7,10,13,16-hexaoxacyclooctadecane)dipotassium]-µ₂-iodido-(iodidocadmium)-di-µ₂-iodido-(iodidocadmium)-µ₂-iodido] top

Crystal data top

[Cd₂K₂I₆(C₁₂H₂₄O₆)₂]	F(000) = 1480
M_r = 796.51	D_x = 2.254 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5995 reflections
a = 10.627 (2) Å	θ = 2.4–31.1°
b = 14.986 (2) Å	µ = 5.07 mm⁻¹
c = 15.190 (3) Å	T = 293 K
β = 103.959 (1)°	Block, colorless
V = 2347.7 (7) Å³	0.20 × 0.15 × 0.10 mm
Z = 4

Data collection top

Bruker Kappa APEXII CCD diffractometer	4129 independent reflections
Radiation source: fine-focus sealed tube	3585 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
ω and ϕ scans	θ_max = 25.0°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −12→12
T_min = 0.430, T_max = 0.631	k = −17→17
21969 measured reflections	l = −18→17

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.028	H-atom parameters constrained
wR(F²) = 0.067	w = 1/[σ²(F_o²) + (0.023P)² + 7.1196P] where P = (F_o² + 2F_c²)/3
S = 1.03	(Δ/σ)_max < 0.001
4129 reflections	Δρ_max = 1.53 e Å⁻³
219 parameters	Δρ_min = −1.16 e Å⁻³
6 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00235 (8)

Crystal data top

[Cd₂K₂I₆(C₁₂H₂₄O₆)₂]	V = 2347.7 (7) Å³
M_r = 796.51	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.627 (2) Å	µ = 5.07 mm⁻¹
b = 14.986 (2) Å	T = 293 K
c = 15.190 (3) Å	0.20 × 0.15 × 0.10 mm
β = 103.959 (1)°

Data collection top

Bruker Kappa APEXII CCD diffractometer	4129 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	3585 reflections with I > 2σ(I)
T_min = 0.430, T_max = 0.631	R_int = 0.025
21969 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.028	6 restraints
wR(F²) = 0.067	H-atom parameters constrained
S = 1.03	Δρ_max = 1.53 e Å⁻³
4129 reflections	Δρ_min = −1.16 e Å⁻³
219 parameters

Special details top

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 F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
C1	0.3249 (6)	0.2719 (4)	0.4090 (5)	0.0679 (16)
H1A	0.3011	0.3261	0.3740	0.081*	0.772 (18)
H1B	0.3200	0.2840	0.4708	0.081*	0.772 (18)
H1C	0.2860	0.2977	0.3501	0.081*	0.228 (18)
H1D	0.3298	0.3192	0.4533	0.081*	0.228 (18)
C2	0.2332 (7)	0.2020 (6)	0.3714 (8)	0.060 (2)	0.772 (18)
H2A	0.1481	0.2182	0.3790	0.072*	0.772 (18)
H2B	0.2275	0.1966	0.3070	0.072*	0.772 (18)
C2'	0.238 (3)	0.2087 (18)	0.426 (3)	0.055 (5)	0.228 (18)
H2'1	0.1528	0.2214	0.3879	0.066*	0.228 (18)
H2'2	0.2320	0.2155	0.4889	0.066*	0.228 (18)
C3	0.1840 (7)	0.0503 (5)	0.3846 (7)	0.110 (3)
H3A	0.1013	0.0665	0.3965	0.131*
H3B	0.1705	0.0449	0.3193	0.131*
C4	0.2172 (7)	−0.0310 (5)	0.4214 (7)	0.104 (3)
H4A	0.1537	−0.0738	0.3898	0.125*
H4B	0.2110	−0.0294	0.4840	0.125*
C5	0.3433 (6)	−0.1295 (4)	0.3525 (4)	0.0606 (14)
H5A	0.3073	−0.1049	0.2927	0.073*
H5B	0.2900	−0.1796	0.3614	0.073*
C6	0.4776 (6)	−0.1597 (3)	0.3595 (4)	0.0577 (14)
H6A	0.5175	−0.1768	0.4216	0.069*
H6B	0.4772	−0.2115	0.3210	0.069*
C7	0.6773 (6)	−0.1139 (4)	0.3315 (4)	0.0660 (16)
H7A	0.6775	−0.1703	0.3001	0.079*
H7B	0.7289	−0.1208	0.3932	0.079*
C8	0.7332 (6)	−0.0427 (4)	0.2846 (4)	0.0678 (16)
H8A	0.8191	−0.0600	0.2795	0.081*
H8B	0.6792	−0.0342	0.2238	0.081*
C9	0.7834 (6)	0.1110 (4)	0.2893 (4)	0.0642 (15)
H9A	0.7216	0.1224	0.2321	0.077*
H9B	0.8665	0.0970	0.2767	0.077*
C10	0.7961 (5)	0.1915 (4)	0.3483 (5)	0.0684 (16)
H10A	0.8492	0.1779	0.4082	0.082*
H10B	0.8373	0.2394	0.3226	0.082*
C11	0.6678 (6)	0.2865 (4)	0.4144 (5)	0.0721 (17)
H11A	0.7194	0.3358	0.4010	0.087*
H11B	0.7072	0.2660	0.4754	0.087*
C12	0.5374 (6)	0.3184 (4)	0.4112 (5)	0.0760 (18)
H12A	0.5394	0.3550	0.4642	0.091*
H12B	0.5081	0.3555	0.3579	0.091*
O1	0.4507 (4)	0.2494 (2)	0.4086 (3)	0.0636 (10)
O2	0.2691 (3)	0.1203 (2)	0.4130 (3)	0.0595 (9)
O3	0.3430 (4)	−0.0632 (2)	0.4197 (3)	0.0616 (10)
O4	0.5494 (4)	−0.0901 (2)	0.3323 (2)	0.0539 (9)
O5	0.7407 (4)	0.0380 (2)	0.3341 (2)	0.0568 (9)
O6	0.6704 (4)	0.2180 (3)	0.3542 (3)	0.0680 (11)
K1	0.51194 (11)	0.07876 (7)	0.38443 (8)	0.0520 (3)
Cd1	0.10508 (3)	0.09039 (2)	0.07415 (2)	0.04486 (11)
I1	−0.01908 (3)	−0.06719 (2)	0.11826 (2)	0.05110 (11)
I2	−0.00034 (4)	0.23919 (3)	0.12810 (3)	0.06725 (14)
I3	0.36601 (3)	0.07316 (3)	0.13778 (3)	0.05971 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.070 (4)	0.049 (3)	0.089 (4)	0.022 (3)	0.030 (3)	0.009 (3)
C2	0.050 (4)	0.066 (5)	0.059 (6)	0.019 (3)	0.004 (4)	0.005 (5)
C2'	0.048 (8)	0.060 (9)	0.058 (10)	0.024 (8)	0.012 (10)	0.002 (10)
C3	0.045 (4)	0.076 (5)	0.198 (10)	−0.006 (4)	0.009 (5)	0.005 (6)
C4	0.063 (4)	0.074 (5)	0.186 (9)	−0.012 (4)	0.052 (5)	−0.010 (5)
C5	0.071 (4)	0.050 (3)	0.059 (3)	−0.012 (3)	0.013 (3)	−0.002 (3)
C6	0.082 (4)	0.038 (3)	0.055 (3)	0.000 (3)	0.019 (3)	0.000 (2)
C7	0.069 (4)	0.049 (3)	0.085 (4)	0.018 (3)	0.028 (3)	−0.001 (3)
C8	0.072 (4)	0.065 (4)	0.076 (4)	0.011 (3)	0.038 (3)	−0.011 (3)
C9	0.053 (3)	0.076 (4)	0.070 (4)	−0.003 (3)	0.028 (3)	0.004 (3)
C10	0.050 (3)	0.070 (4)	0.089 (4)	−0.011 (3)	0.024 (3)	−0.002 (3)
C11	0.068 (4)	0.065 (4)	0.079 (4)	−0.010 (3)	0.009 (3)	−0.011 (3)
C12	0.086 (5)	0.046 (3)	0.100 (5)	−0.010 (3)	0.031 (4)	−0.013 (3)
O1	0.058 (2)	0.045 (2)	0.088 (3)	0.0044 (18)	0.018 (2)	−0.0001 (19)
O2	0.049 (2)	0.051 (2)	0.078 (3)	0.0035 (17)	0.0144 (19)	0.0012 (18)
O3	0.060 (2)	0.049 (2)	0.078 (3)	−0.0065 (18)	0.022 (2)	−0.0076 (18)
O4	0.061 (2)	0.0392 (18)	0.065 (2)	0.0083 (16)	0.0214 (18)	0.0028 (16)
O5	0.062 (2)	0.059 (2)	0.056 (2)	0.0023 (18)	0.0263 (18)	−0.0008 (17)
O6	0.058 (2)	0.058 (2)	0.092 (3)	−0.0112 (19)	0.024 (2)	−0.013 (2)
K1	0.0499 (6)	0.0392 (6)	0.0724 (8)	−0.0007 (5)	0.0256 (6)	−0.0059 (5)
Cd1	0.0438 (2)	0.0415 (2)	0.0481 (2)	−0.00042 (15)	0.00872 (15)	−0.00202 (15)
I1	0.0600 (2)	0.0530 (2)	0.04247 (19)	−0.01331 (16)	0.01657 (15)	0.00179 (14)
I2	0.0590 (2)	0.0554 (2)	0.0825 (3)	0.01439 (18)	0.0077 (2)	−0.01480 (19)
I3	0.0436 (2)	0.0646 (2)	0.0658 (2)	0.00437 (16)	0.00337 (16)	0.00944 (17)

Geometric parameters (Å, º) top

C1—O1	1.380 (7)	C8—O5	1.416 (6)
C1—C2'	1.39 (3)	C8—H8A	0.9700
C1—C2	1.451 (11)	C8—H8B	0.9700
C1—H1A	0.9700	C9—O5	1.419 (7)
C1—H1B	0.9700	C9—C10	1.489 (8)
C1—H1C	0.9700	C9—H9A	0.9700
C1—H1D	0.9700	C9—H9B	0.9700
C2—O2	1.388 (9)	C10—O6	1.417 (7)
C2—K1	3.456 (8)	C10—H10A	0.9700
C2—H2A	0.9700	C10—H10B	0.9700
C2—H2B	0.9700	C11—O6	1.379 (7)
C2'—O2	1.39 (3)	C11—C12	1.455 (8)
C2'—H2'1	0.9700	C11—K1	3.504 (6)
C2'—H2'2	0.9700	C11—H11A	0.9700
C3—C4	1.352 (10)	C11—H11B	0.9700
C3—O2	1.383 (8)	C12—O1	1.380 (7)
C3—H3A	0.9700	C12—H12A	0.9700
C3—H3B	0.9700	C12—H12B	0.9700
C4—O3	1.427 (8)	O1—K1	2.686 (4)
C4—H4A	0.9700	O2—K1	2.788 (4)
C4—H4B	0.9700	O3—K1	2.916 (4)
C5—O3	1.424 (6)	O3—K1ⁱ	3.011 (4)
C5—C6	1.477 (8)	O4—K1	2.709 (3)
C5—H5A	0.9700	O5—K1	2.786 (4)
C5—H5B	0.9700	O6—K1	2.788 (4)
C6—O4	1.413 (6)	K1—O3ⁱ	3.011 (4)
C6—H6A	0.9700	Cd1—I2	2.7097 (6)
C6—H6B	0.9700	Cd1—I3	2.7197 (7)
C7—O4	1.408 (6)	Cd1—I1	2.8624 (6)
C7—C8	1.485 (8)	Cd1—I1ⁱⁱ	2.8652 (7)
C7—H7A	0.9700	I1—Cd1ⁱⁱ	2.8652 (7)
C7—H7B	0.9700

O1—C1—C2'	121.5 (11)	C11—C12—H12B	109.2
O1—C1—C2	112.4 (5)	H12A—C12—H12B	107.9
O1—C1—H1A	109.1	C12—O1—C1	117.3 (4)
C2'—C1—H1A	125.1	C12—O1—K1	122.4 (3)
C2—C1—H1A	109.1	C1—O1—K1	120.0 (3)
O1—C1—H1B	109.1	C3—O2—C2	116.1 (6)
C2'—C1—H1B	75.5	C3—O2—C2'	127.2 (12)
C2—C1—H1B	109.1	C3—O2—K1	110.0 (4)
H1A—C1—H1B	107.9	C2—O2—K1	106.8 (4)
O1—C1—H1C	107.0	C2'—O2—K1	119.8 (12)
C2'—C1—H1C	107.0	C5—O3—C4	114.3 (5)
C2—C1—H1C	80.2	C5—O3—K1	105.6 (3)
H1B—C1—H1C	135.0	C4—O3—K1	112.2 (4)
O1—C1—H1D	106.9	C5—O3—K1ⁱ	124.4 (3)
C2'—C1—H1D	106.9	C4—O3—K1ⁱ	105.5 (5)
C2—C1—H1D	136.0	K1—O3—K1ⁱ	92.68 (11)
H1A—C1—H1D	74.4	C7—O4—C6	113.9 (4)
H1C—C1—H1D	106.7	C7—O4—K1	116.7 (3)
O2—C2—C1	112.0 (6)	C6—O4—K1	118.5 (3)
O2—C2—K1	50.6 (3)	C8—O5—C9	112.8 (4)
C1—C2—K1	83.0 (4)	C8—O5—K1	113.1 (3)
O2—C2—H2A	109.2	C9—O5—K1	111.4 (3)
C1—C2—H2A	109.2	C11—O6—C10	114.9 (5)
K1—C2—H2A	159.8	C11—O6—K1	109.8 (3)
O2—C2—H2B	109.2	C10—O6—K1	114.6 (3)
C1—C2—H2B	109.2	O1—K1—O4	170.67 (13)
K1—C2—H2B	81.8	O1—K1—O5	120.16 (12)
H2A—C2—H2B	107.9	O4—K1—O5	61.03 (11)
C1—C2'—O2	115 (2)	O1—K1—O6	59.05 (12)
C1—C2'—H2'1	108.5	O4—K1—O6	120.91 (12)
O2—C2'—H2'1	108.5	O5—K1—O6	61.14 (11)
C1—C2'—H2'2	108.5	O1—K1—O2	60.16 (11)
O2—C2'—H2'2	108.5	O4—K1—O2	117.43 (12)
H2'1—C2'—H2'2	107.5	O5—K1—O2	173.22 (12)
C4—C3—O2	117.9 (7)	O6—K1—O2	118.49 (12)
C4—C3—K1	87.1 (4)	O1—K1—O3	119.29 (12)
O2—C3—K1	48.2 (3)	O4—K1—O3	60.85 (11)
C4—C3—H3A	107.8	O5—K1—O3	120.48 (11)
O2—C3—H3A	107.8	O6—K1—O3	178.21 (12)
K1—C3—H3A	156.0	O2—K1—O3	60.01 (11)
C4—C3—H3B	107.8	O1—K1—O3ⁱ	91.24 (12)
O2—C3—H3B	107.8	O4—K1—O3ⁱ	98.07 (11)
K1—C3—H3B	84.9	O5—K1—O3ⁱ	88.95 (11)
H3A—C3—H3B	107.2	O6—K1—O3ⁱ	91.99 (12)
C3—C4—O3	116.7 (7)	O2—K1—O3ⁱ	97.83 (11)
C3—C4—H4A	108.1	O3—K1—O3ⁱ	87.32 (11)
O3—C4—H4A	108.1	O1—K1—C2	42.81 (17)
C3—C4—H4B	108.1	O4—K1—C2	131.82 (18)
O3—C4—H4B	108.1	O5—K1—C2	153.38 (19)
H4A—C4—H4B	107.3	O6—K1—C2	97.71 (17)
O3—C5—C6	109.4 (4)	O2—K1—C2	22.61 (18)
O3—C5—H5A	109.8	O3—K1—C2	80.96 (17)
C6—C5—H5A	109.8	O3ⁱ—K1—C2	109.0 (2)
O3—C5—H5B	109.8	O1—K1—C11	42.17 (14)
C6—C5—H5B	109.8	O4—K1—C11	140.31 (14)
H5A—C5—H5B	108.2	O5—K1—C11	79.29 (13)
O4—C6—C5	109.5 (4)	O6—K1—C11	21.74 (13)
O4—C6—H6A	109.8	O2—K1—C11	101.99 (13)
C5—C6—H6A	109.8	O3—K1—C11	156.50 (14)
O4—C6—H6B	109.8	O3ⁱ—K1—C11	80.03 (13)
C5—C6—H6B	109.8	C2—K1—C11	84.52 (18)
H6A—C6—H6B	108.2	O1—K1—C3	80.91 (15)
O4—C7—C8	108.6 (5)	O4—K1—C3	95.91 (16)
O4—C7—H7A	110.0	O5—K1—C3	154.87 (17)
C8—C7—H7A	110.0	O6—K1—C3	136.86 (16)
O4—C7—H7B	110.0	O2—K1—C3	21.72 (16)
C8—C7—H7B	110.0	O3—K1—C3	41.94 (15)
H7A—C7—H7B	108.3	O3ⁱ—K1—C3	105.17 (19)
O5—C8—C7	109.7 (5)	C2—K1—C3	39.42 (19)
O5—C8—H8A	109.7	C11—K1—C3	123.07 (17)
C7—C8—H8A	109.7	O1—K1—I3	95.98 (9)
O5—C8—H8B	109.7	O4—K1—I3	74.79 (8)
C7—C8—H8B	109.7	O5—K1—I3	84.10 (8)
H8A—C8—H8B	108.2	O6—K1—I3	88.43 (9)
O5—C9—C10	109.2 (5)	O2—K1—I3	89.13 (9)
O5—C9—H9A	109.8	O3—K1—I3	92.49 (9)
C10—C9—H9A	109.8	O3ⁱ—K1—I3	171.82 (8)
O5—C9—H9B	109.8	C2—K1—I3	79.04 (19)
C10—C9—H9B	109.8	C11—K1—I3	102.81 (11)
H9A—C9—H9B	108.3	C3—K1—I3	79.86 (18)
O6—C10—C9	108.4 (5)	O1—K1—K1ⁱ	110.35 (10)
O6—C10—H10A	110.0	O4—K1—K1ⁱ	76.54 (8)
C9—C10—H10A	110.0	O5—K1—K1ⁱ	109.39 (9)
O6—C10—H10B	110.0	O6—K1—K1ⁱ	134.75 (10)
C9—C10—H10B	110.0	O2—K1—K1ⁱ	75.86 (8)
H10A—C10—H10B	108.4	O3—K1—K1ⁱ	44.54 (8)
O6—C11—C12	113.2 (5)	O3ⁱ—K1—K1ⁱ	42.78 (7)
O6—C11—K1	48.5 (3)	C2—K1—K1ⁱ	96.98 (18)
C12—C11—K1	82.6 (3)	C11—K1—K1ⁱ	120.13 (12)
O6—C11—H11A	108.9	C3—K1—K1ⁱ	71.22 (16)
C12—C11—H11A	108.9	I3—K1—K1ⁱ	136.43 (4)
K1—C11—H11A	157.3	I2—Cd1—I3	115.538 (18)
O6—C11—H11B	108.9	I2—Cd1—I1	111.13 (2)
C12—C11—H11B	108.9	I3—Cd1—I1	109.058 (17)
K1—C11—H11B	85.7	I2—Cd1—I1ⁱⁱ	110.792 (17)
H11A—C11—H11B	107.8	I3—Cd1—I1ⁱⁱ	113.455 (17)
O1—C12—C11	112.3 (5)	I1—Cd1—I1ⁱⁱ	94.994 (15)
O1—C12—H12A	109.2	Cd1—I1—Cd1ⁱⁱ	85.006 (15)
C11—C12—H12A	109.2	Cd1—I3—K1	120.06 (2)
O1—C12—H12B	109.2

O1—C1—C2—O2	52.9 (10)	C3—O2—K1—O4	−8.3 (5)
C2'—C1—C2—O2	−60.7 (19)	C2—O2—K1—O4	−135.1 (5)
O1—C1—C2—K1	10.6 (5)	C2'—O2—K1—O4	−170.4 (18)
C2'—C1—C2—K1	−103 (2)	C3—O2—K1—O6	151.8 (5)
O1—C1—C2'—O2	−21 (3)	C2—O2—K1—O6	25.0 (5)
C2—C1—C2'—O2	63 (2)	C2'—O2—K1—O6	−10.3 (19)
O2—C3—C4—O3	−51.3 (13)	C3—O2—K1—O3	−29.3 (5)
K1—C3—C4—O3	−12.7 (8)	C2—O2—K1—O3	−156.1 (5)
O3—C5—C6—O4	−68.8 (6)	C2'—O2—K1—O3	168.6 (19)
O4—C7—C8—O5	63.5 (6)	C3—O2—K1—O3ⁱ	−111.6 (5)
O5—C9—C10—O6	−68.1 (6)	C2—O2—K1—O3ⁱ	121.6 (5)
O6—C11—C12—O1	44.6 (8)	C2'—O2—K1—O3ⁱ	86.2 (18)
K1—C11—C12—O1	6.1 (5)	C3—O2—K1—C2	126.8 (7)
C11—C12—O1—C1	177.6 (6)	C2'—O2—K1—C2	−35.3 (16)
C11—C12—O1—K1	−9.4 (8)	C3—O2—K1—C11	167.0 (5)
C2'—C1—O1—C12	−166 (2)	C2—O2—K1—C11	40.2 (5)
C2—C1—O1—C12	157.4 (7)	C2'—O2—K1—C11	4.8 (18)
C2'—C1—O1—K1	21 (2)	C2—O2—K1—C3	−126.8 (7)
C2—C1—O1—K1	−15.8 (8)	C2'—O2—K1—C3	−162.1 (19)
C4—C3—O2—C2	178.1 (9)	C3—O2—K1—I3	64.1 (5)
K1—C3—O2—C2	121.4 (7)	C2—O2—K1—I3	−62.7 (5)
C4—C3—O2—C2'	−143 (2)	C2'—O2—K1—I3	−98.1 (18)
K1—C3—O2—C2'	160 (2)	C3—O2—K1—K1ⁱ	−74.6 (5)
C4—C3—O2—K1	56.6 (10)	C2—O2—K1—K1ⁱ	158.6 (5)
C1—C2—O2—C3	177.0 (7)	C2'—O2—K1—K1ⁱ	123.2 (18)
K1—C2—O2—C3	−123.1 (7)	C5—O3—K1—O1	143.2 (3)
C1—C2—O2—C2'	58 (2)	C4—O3—K1—O1	18.0 (5)
K1—C2—O2—C2'	118 (2)	K1ⁱ—O3—K1—O1	−89.92 (14)
C1—C2—O2—K1	−59.9 (8)	C5—O3—K1—O4	−26.1 (3)
C1—C2'—O2—C3	−148.2 (16)	C4—O3—K1—O4	−151.3 (5)
C1—C2'—O2—C2	−65 (3)	K1ⁱ—O3—K1—O4	100.78 (13)
C1—C2'—O2—K1	11 (3)	C5—O3—K1—O5	−39.7 (4)
C6—C5—O3—C4	−178.0 (5)	C4—O3—K1—O5	−164.9 (5)
C6—C5—O3—K1	58.1 (5)	K1ⁱ—O3—K1—O5	87.20 (13)
C6—C5—O3—K1ⁱ	−46.3 (5)	C5—O3—K1—O2	132.5 (3)
C3—C4—O3—C5	−103.7 (8)	C4—O3—K1—O2	7.3 (5)
C3—C4—O3—K1	16.6 (10)	K1ⁱ—O3—K1—O2	−100.63 (13)
C3—C4—O3—K1ⁱ	116.1 (8)	C5—O3—K1—O3ⁱ	−126.9 (3)
C8—C7—O4—C6	168.6 (5)	C4—O3—K1—O3ⁱ	107.9 (5)
C8—C7—O4—K1	−47.6 (6)	K1ⁱ—O3—K1—O3ⁱ	0.0
C5—C6—O4—C7	−176.6 (5)	C5—O3—K1—C2	123.4 (4)
C5—C6—O4—K1	40.3 (5)	C4—O3—K1—C2	−1.8 (5)
C7—C8—O5—C9	−175.2 (5)	K1ⁱ—O3—K1—C2	−109.7 (2)
C7—C8—O5—K1	−47.7 (6)	C5—O3—K1—C11	175.9 (4)
C10—C9—O5—C8	−176.6 (5)	C4—O3—K1—C11	50.8 (6)
C10—C9—O5—K1	55.0 (5)	K1ⁱ—O3—K1—C11	−57.2 (4)
C12—C11—O6—C10	173.5 (5)	C5—O3—K1—C3	116.8 (4)
K1—C11—O6—C10	−130.9 (5)	C4—O3—K1—C3	−8.4 (5)
C12—C11—O6—K1	−55.5 (6)	K1ⁱ—O3—K1—C3	−116.4 (3)
C9—C10—O6—C11	173.6 (5)	C5—O3—K1—I3	44.9 (3)
C9—C10—O6—K1	45.0 (6)	C4—O3—K1—I3	−80.3 (5)
C12—O1—K1—O5	−10.5 (5)	K1ⁱ—O3—K1—I3	171.81 (8)
C1—O1—K1—O5	162.3 (4)	C5—O3—K1—K1ⁱ	−126.9 (3)
C12—O1—K1—O6	−12.6 (4)	C4—O3—K1—K1ⁱ	107.9 (5)
C1—O1—K1—O6	160.3 (4)	O2—C2—K1—O1	−133.4 (7)
C12—O1—K1—O2	177.3 (5)	C1—C2—K1—O1	−7.4 (4)
C1—O1—K1—O2	−9.8 (4)	O2—C2—K1—O4	57.3 (6)
C12—O1—K1—O3	166.6 (4)	C1—C2—K1—O4	−176.7 (4)
C1—O1—K1—O3	−20.5 (5)	O2—C2—K1—O5	166.8 (3)
C12—O1—K1—O3ⁱ	79.0 (5)	C1—C2—K1—O5	−67.1 (8)
C1—O1—K1—O3ⁱ	−108.2 (4)	O2—C2—K1—O6	−158.0 (5)
C12—O1—K1—C2	−163.9 (6)	C1—C2—K1—O6	−31.9 (5)
C1—O1—K1—C2	8.9 (5)	C1—C2—K1—O2	126.0 (9)
C12—O1—K1—C11	5.4 (4)	O2—C2—K1—O3	20.8 (5)
C1—O1—K1—C11	178.2 (5)	C1—C2—K1—O3	146.9 (5)
C12—O1—K1—C3	−175.8 (5)	O2—C2—K1—O3ⁱ	−63.2 (5)
C1—O1—K1—C3	−3.0 (4)	C1—C2—K1—O3ⁱ	62.9 (5)
C12—O1—K1—I3	−97.1 (5)	O2—C2—K1—C11	−140.6 (5)
C1—O1—K1—I3	75.7 (4)	C1—C2—K1—C11	−14.6 (5)
C12—O1—K1—K1ⁱ	118.2 (4)	O2—C2—K1—C3	27.8 (4)
C1—O1—K1—K1ⁱ	−69.0 (4)	C1—C2—K1—C3	153.9 (8)
C7—O4—K1—O5	16.9 (3)	O2—C2—K1—I3	115.1 (5)
C6—O4—K1—O5	159.0 (4)	C1—C2—K1—I3	−118.8 (5)
C7—O4—K1—O6	29.8 (4)	O2—C2—K1—K1ⁱ	−20.9 (5)
C6—O4—K1—O6	172.0 (3)	C1—C2—K1—K1ⁱ	105.1 (5)
C7—O4—K1—O2	−170.6 (3)	O6—C11—K1—O1	−134.5 (5)
C6—O4—K1—O2	−28.5 (4)	C12—C11—K1—O1	−4.3 (4)
C7—O4—K1—O3	−149.8 (4)	O6—C11—K1—O4	31.8 (5)
C6—O4—K1—O3	−7.6 (3)	C12—C11—K1—O4	161.9 (4)
C7—O4—K1—O3ⁱ	−67.4 (4)	O6—C11—K1—O5	31.6 (4)
C6—O4—K1—O3ⁱ	74.7 (4)	C12—C11—K1—O5	161.7 (4)
C7—O4—K1—C2	168.0 (4)	C12—C11—K1—O6	130.1 (6)
C6—O4—K1—C2	−49.8 (5)	O6—C11—K1—O2	−141.6 (4)
C7—O4—K1—C11	16.7 (5)	C12—C11—K1—O2	−11.5 (4)
C6—O4—K1—C11	158.8 (4)	O6—C11—K1—O3	−179.1 (3)
C7—O4—K1—C3	−173.7 (4)	C12—C11—K1—O3	−49.0 (6)
C6—O4—K1—C3	−31.5 (4)	O6—C11—K1—O3ⁱ	122.4 (4)
C7—O4—K1—I3	108.5 (4)	C12—C11—K1—O3ⁱ	−107.4 (4)
C6—O4—K1—I3	−109.3 (3)	O6—C11—K1—C2	−127.2 (4)
C7—O4—K1—K1ⁱ	−104.6 (4)	C12—C11—K1—C2	3.0 (4)
C6—O4—K1—K1ⁱ	37.5 (3)	O6—C11—K1—C3	−135.9 (4)
C8—O5—K1—O1	−152.3 (3)	C12—C11—K1—C3	−5.7 (5)
C9—O5—K1—O1	−24.1 (4)	O6—C11—K1—I3	−49.8 (4)
C8—O5—K1—O4	17.0 (3)	C12—C11—K1—I3	80.4 (4)
C9—O5—K1—O4	145.2 (4)	O6—C11—K1—K1ⁱ	137.9 (3)
C8—O5—K1—O6	−150.3 (4)	C12—C11—K1—K1ⁱ	−91.9 (4)
C9—O5—K1—O6	−22.1 (3)	C4—C3—K1—O1	−148.6 (6)
C8—O5—K1—O3	30.6 (4)	O2—C3—K1—O1	−16.2 (5)
C9—O5—K1—O3	158.8 (3)	C4—C3—K1—O4	40.3 (6)
C8—O5—K1—O3ⁱ	116.9 (4)	O2—C3—K1—O4	172.6 (5)
C9—O5—K1—O3ⁱ	−114.9 (3)	C4—C3—K1—O5	62.4 (9)
C8—O5—K1—C2	−109.6 (5)	O2—C3—K1—O5	−165.2 (3)
C9—O5—K1—C2	18.6 (6)	C4—C3—K1—O6	−169.8 (5)
C8—O5—K1—C11	−163.1 (4)	O2—C3—K1—O6	−37.4 (6)
C9—O5—K1—C11	−34.9 (3)	C4—C3—K1—O2	−132.4 (10)
C8—O5—K1—C3	−8.4 (6)	C4—C3—K1—O3	8.2 (5)
C9—O5—K1—C3	119.8 (5)	O2—C3—K1—O3	140.6 (6)
C8—O5—K1—I3	−58.8 (3)	C4—C3—K1—O3ⁱ	−59.8 (6)
C9—O5—K1—I3	69.4 (3)	O2—C3—K1—O3ⁱ	72.6 (5)
C8—O5—K1—K1ⁱ	78.6 (4)	C4—C3—K1—C2	−161.4 (8)
C9—O5—K1—K1ⁱ	−153.3 (3)	O2—C3—K1—C2	−29.0 (4)
C11—O6—K1—O1	33.9 (4)	C4—C3—K1—C11	−147.6 (6)
C10—O6—K1—O1	165.0 (4)	O2—C3—K1—C11	−15.3 (6)
C11—O6—K1—O4	−156.9 (4)	C4—C3—K1—I3	113.6 (6)
C10—O6—K1—O4	−25.9 (4)	O2—C3—K1—I3	−114.0 (5)
C11—O6—K1—O5	−144.0 (4)	C4—C3—K1—K1ⁱ	−33.3 (6)
C10—O6—K1—O5	−12.9 (4)	O2—C3—K1—K1ⁱ	99.0 (5)
C11—O6—K1—O2	43.7 (4)	I2—Cd1—I1—Cd1ⁱⁱ	114.57 (2)
C10—O6—K1—O2	174.8 (4)	I3—Cd1—I1—Cd1ⁱⁱ	−116.930 (19)
C11—O6—K1—O3ⁱ	−56.3 (4)	I1ⁱⁱ—Cd1—I1—Cd1ⁱⁱ	0.0
C10—O6—K1—O3ⁱ	74.8 (4)	I2—Cd1—I3—K1	55.85 (3)
C11—O6—K1—C2	53.2 (4)	I1—Cd1—I3—K1	−70.15 (3)
C10—O6—K1—C2	−175.8 (4)	I1ⁱⁱ—Cd1—I3—K1	−174.64 (2)
C10—O6—K1—C11	131.1 (6)	O1—K1—I3—Cd1	−65.72 (9)
C11—O6—K1—C3	58.5 (5)	O4—K1—I3—Cd1	112.93 (8)
C10—O6—K1—C3	−170.4 (4)	O5—K1—I3—Cd1	174.47 (8)
C11—O6—K1—I3	131.9 (4)	O6—K1—I3—Cd1	−124.39 (9)
C10—O6—K1—I3	−97.0 (4)	O2—K1—I3—Cd1	−5.86 (8)
C11—O6—K1—K1ⁱ	−54.7 (4)	O3—K1—I3—Cd1	54.07 (8)
C10—O6—K1—K1ⁱ	76.4 (4)	C2—K1—I3—Cd1	−26.22 (15)
C3—O2—K1—O1	161.4 (5)	C11—K1—I3—Cd1	−107.96 (11)
C2—O2—K1—O1	34.7 (5)	C3—K1—I3—Cd1	13.90 (13)
C2'—O2—K1—O1	−0.7 (18)	K1ⁱ—K1—I3—Cd1	62.41 (7)

Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x, −y, −z.

Experimental details

Crystal data
Chemical formula	[Cd₂K₂I₆(C₁₂H₂₄O₆)₂]
M_r	796.51
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	10.627 (2), 14.986 (2), 15.190 (3)
β (°)	103.959 (1)
V (Å³)	2347.7 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	5.07
Crystal size (mm)	0.20 × 0.15 × 0.10

Data collection
Diffractometer	Bruker Kappa APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2004)
T_min, T_max	0.430, 0.631
No. of measured, independent and observed [I > 2σ(I)] reflections	21969, 4129, 3585
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.067, 1.03
No. of reflections	4129
No. of parameters	219
No. of restraints	6
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.53, −1.16

Computer programs: APEX2 (Bruker, 2004), APEX2 and SAINT (Bruker, 2004), SAINT and XPREP (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008), WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Acknowledgements

The authors thank Dr Babu Vargheese, SAIF, IIT, Madras, India, for his help in collecting the X-ray intensity data. KR thanks the University Grants Commission for financial support granted under a Major Research Project [F. No. 41–1008/2012 (SR)].

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