catena-Poly[[[aqua­cadmium(II)]bis­(μ-4-hydroxy­pyridine-2,6-dicarboxyl­ato)[aqua­cadmium(II)]di-μ-aqua] tetra­hydrate]

Aghabozorg, H.; Ilaie, N.; Heidari, M.; Manteghi, F.; Pasdar, H.

doi:10.1107/S1600536808030869

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 10| October 2008| Pages m1351-m1352

doi:10.1107/S1600536808030869

Open

access

catena-Poly[[[aquacadmium(II)]bis(μ-4-hydroxypyridine-2,6-dicarboxylato)[aquacadmium(II)]di-μ-aqua] tetrahydrate]

Hossein Aghabozorg,^a ^* Neda Ilaie,^b Mohammad Heidari,^a Faranak Manteghi ^c and Hoda Pasdar ^b

^aFaculty of Chemistry, Tarbiat Moallem University, Tehran, Iran, ^bFaculty of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, Iran, and ^cFaculty of Chemistry, Iran University of Science and Technology, Tehran, Iran
^*Correspondence e-mail: haghabozorg@yahoo.com

(Received 16 August 2008; accepted 24 September 2008; online 30 September 2008)

The title polymeric compound, {[Cd₂(C₇H₃NO₅)₂(H₂O)₄]·4H₂O}_n or {[Cd₂(hypydc)₂(H₂O)₄]·4H₂O}_n (where hypydcH₂ is 4-hydroxypyridine-2,6-dicarboxylic acid), was synthesized by the reaction of cadmium(II) nitrate hexahydrate with 4-hydroxypyridine-2,6-dicarboxylic acid and propane-1,3-diamine, in a 1:2:2 molar ratio in aqueous solution. The compound is a seven-coordinate binuclear polymeric complex with distorted pentagonal bipyramidal geometry around Cd^II [Cd—O = 2.247 (4)–2.474 (3) Å]. In the binuclear monomeric units, the central atoms join together by O atoms of two bridging tridentate (hypydc)²⁻ ligands, and the polymer propagates via two bridging water molecules that link each Cd^IIcentre of one monomer to the adjacent neighbour. Propane-1,3-diamine (pn) does not appear in the product but plays a role as a base. Intermolecular O—H⋯O and C—H⋯O hydrogen bonds, and π–π stacking interactions, with distances of 3.725 (3) and 3.766 (3) Å, connect the various components.

Related literature

For a review of proton-transfer compounds, see: Aghabozorg, Manteghi & Sheshmani (2008 ). For related compounds, see: Aghabozorg et al. (2007 ); Aghabozorg, Motyeian et al. (2008 ); Aghabozorg, Roshan et al. (2008 ); Fu et al. (2004 ); Odoko et al. (2002 ); Ranjbar et al. (2002 ); Wu et al. (2007 ). For the isostructural Mn compound, see: Ghosh et al. (2005 ).

Experimental

Crystal data

[Cd₂(C₇H₃NO₅)₂(H₂O)₄]·4H₂O
M_r = 731.14
Triclinic, $[P \overline 1]$
a = 9.4499 (6) Å
b = 10.8633 (7) Å
c = 11.2086 (9) Å
α = 87.910 (3)°
β = 74.239 (2)°
γ = 80.478 (2)°
V = 1092.08 (13) Å³
Z = 2
Mo Kα radiation
μ = 2.04 mm⁻¹
T = 100 (2) K
0.15 × 0.12 × 0.08 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ) T_min = 0.749, T_max = 0.854
14393 measured reflections
6313 independent reflections
4460 reflections with I > 2σ(I)
R_int = 0.059

Refinement

R[F² > 2σ(F²)] = 0.052
wR(F²) = 0.091
S = 1.00
6313 reflections
265 parameters
H-atom parameters constrained
Δρ_max = 1.03 e Å⁻³
Δρ_min = −1.01 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3O⋯O9ⁱ	0.85	1.74	2.536 (5)	156
O6—H6A⋯O4ⁱⁱ	0.85	1.86	2.665 (5)	156
O6—H6B⋯O17	0.85	1.83	2.677 (8)	177
O7—H7A⋯O11ⁱⁱⁱ	0.85	2.06	2.871 (5)	158
O7—H7B⋯O1^iv	0.85	1.84	2.639 (5)	156
O8—H8A⋯O12^v	0.85	1.88	2.687 (5)	159
O8—H8B⋯O15	0.85	1.83	2.679 (5)	176
O11—H11O⋯O5ⁱⁱⁱ	0.85	1.76	2.547 (5)	153
O14—H14A⋯O18^vi	0.85	1.94	2.747 (7)	159
O14—H14B⋯O16^v	0.85	1.82	2.663 (6)	169
O15—H15A⋯O17^vii	0.85	1.96	2.802 (7)	169
O15—H15B⋯O3ⁱ	0.85	2.03	2.790 (5)	149
O16—H16A⋯O18^viii	0.85	2.30	3.013 (6)	142
O16—H16A⋯O14^ix	0.85	2.50	3.228 (6)	143
O16—H16B⋯O15^ix	0.85	1.97	2.791 (6)	161
O18—H18A⋯O9ⁱⁱ	0.85	1.88	2.719 (5)	170
O18—H18B⋯O12^x	0.85	2.20	2.819 (6)	129
C11—H11A⋯O4ⁱⁱⁱ	0.95	2.31	3.224 (6)	161
Symmetry codes: (i) -x+2, -y+1, -z; (ii) -x+1, -y+1, -z; (iii) -x+1, -y, -z; (iv) -x+1, -y+1, -z+1; (v) -x+1, -y, -z+1; (vi) x+1, y-1, z; (vii) x+1, y, z; (viii) x, y-1, z; (ix) x-1, y, z; (x) x, y+1, z.

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808030869/om2258sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808030869/om2258Isup2.hkl

checkCIF report

Comment top

We have reported a number of cases in which a proton is transferred from a carboxylic acid to an amine to form some novel organic compounds. This work was recently reviewed (Aghabozorg, Manteghi & Sheshmani, 2008). With the use of these organic proton transfer compounds as starting materials, several metal organic compounds were prepared. Recently, we have combined the acid, amine and metallic salt in a one-pot reaction, including the title compound in this article, [Cd₂(hypydc)₂(H₂O)₄]}_n.4nH₂O (where hypydcH₂ is 4-hydroxypyridine-2,6-dicarboxylic acid). A search of the literature shows that there are similar compounds to the title compound using pydc (pydcH₂ = pyridine-2,6-dicarboxylic acid) as ligand to Cd^II such as (enH₂)₂[Cd(pydc)₃].6H₂O, 1 (Fu et al., 2004), or [Cd₂(pydc)₂(H₂O)₆].2pydcH₂, 2(Odoko et al., 2002), [Cd₂(pydc)₂(CH₃OH)₂(H₂O)]_n, 3 (Wu et al., 2007), [Cd(pydc)(H₂O)₃]₂.2H₂pydc, 4 (Ranjbar et al., 2002), [Cd(py-2,3-dc)(H₂O)₃]_n, 5, py-2,3-dc is pyridine-2,3-dicarboxylate, (Aghabozorg, Motyeian et al., 2008) or hypydc as ligand to different metals such as (pydaH)[Cr(hypydc)₂].2H₂O (Aghabozorg, Roshan, et al., 2008), [Ni(hypydc)(H₂O)₃].1.5H₂O (Aghabozorg, Ghadermazi, et al., 2007).

The molecular structure, coordination polyhedra, π–π stacking, packing diagram and water cluster of the title compound are shown in Figs. 1–5. The extensive hydrogen bonding geometry is given in Table 1. Each of the two Cd^II atoms in the asymmetric unit is seven-coordinate. The coordination environment is distorted pentagonal bipyramidal, with two O and one N atoms of the (hypydc)^2- group as well as one O atom of an inversion-related (hypydc)^2- group and a bridging water O atom forming the pentagonal plane. The other bridging water O and one terminal O atom of a coordinated water form the apical groups (Figs. 1 and 2). The sums of the bond angles in the pentagonal plane around Cd1 and Cd2 are 362.05° and 362.89°, respectively. As shown in Fig. 1, the Cd1 and Cd2 atoms join together by O atoms of two bridging water molecules (O7 and O8), and the O atoms of tridentate (hypydc)^2- ligands (O2 and O13) bridge Cd1 to Cd1A and Cd2 to Cd2B to make a polymeric feature. The compound is isostructural to {[Mn₂(hypydc)₂(H₂O)₄]}_n.4nH₂O which has been described as propagating in a one-dimensional staircase model (Ghosh et al., 2005).

Compared with the similar structures mentioned above and listed in Table 2, with various coordination numbers of six, seven and nine, the Cd—O distances of the title compound (average 2.388 Å) lie in the same range as compounds 2, 3, and 4 and far from compounds 1 and 5. However, the Cd—N distances (average 2.273 Å) are obviously shorter than all five compounds. Moreover, in the polymeric compound 3, the binuclear units are connected via carboxylate O atoms to build a one-dimensional polymeric chain, and in 5, the chain propagates via linking two oxygen atoms of (py-2,3-dc)^2- to cadmium centers, while in the title compound, the bridging water molecules cause propagation of the binuclear unit.

An outstanding feature of the title compound is the presence of π–π stacking interactions between aromatic rings, Cg1–Cg2 (Cg1: N1/C1–C5; Cg2: N2/C8–C12) with distances of 3.725 (3) Å (x, 1 + y, z) and Cg2–Cg2 with distances of 3.767 (3) Å (1 - x, -y, -z), as shown in Fig. 3. Intermolecular O—H···O and C—H···O hydrogen bonds with D···A ranging from 2.534 (5) Å to 3.225 (6) Å (Table 1), ion pairing and π–π stacking interactions are observed. The arrangement of water molecules in the structure consists of an R6 motif coupled to a branched C10 motif as shown in Fig. 5.

Related literature top

For a review of proton-transfer compounds, see: Aghabozorg, Manteghi & Sheshmani (2008). For related compounds, see: Aghabozorg et al. (2007); Aghabozorg, Motyeian, et al. (2008); Aghabozorg, Roshan, et al. (2008); Fu et al. (2004); Odoko et al. (2002); Ranjbar et al. (2002); Wu et al. (2007). For the isostructural Mn compound, see: Ghosh et al. (2005).

Experimental top

A solution of Cd(NO₃)₂.6H₂O (172 mg, 0.5 mmol) in water (10 ml) was added to an aqueous solution of propane-1,3-diamine(74 mg, 1 mmol) and 4-hydroxypyridine-2,6-dicarboxylic acid (167 mg, 1 mmol) in water (10 ml) in a 1:2:2 molar ratio and heated for two hours. Colourless crystals of the title compound were obtained after allowing the mixture to stand for four months at room temperature.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound as a fragment of the polymeric chain. Displacement ellipsoids are drawn at 50% probability level. Symmetry codes to generate atoms with labels: A: -x + 1,-y + 1,-z + 1; B: -x + 1, -y, -z + 1.
	Fig. 2. Coordination polyhedron of the title compound [i: (1 - x, 1 - y, 1 - z) and ii: (1 - x, -y, 1 - z)]
	Fig. 3. π–π Stacking interactions of Cg1–Cg2 (Cg1: N1/C1–C5; Cg2: N2/C8–C12) and Cg2–Cg2 of the title compound. The average distances between the planes are 3.725 (3) Å (x, 1 + y, z) and 3.766 (3) Å (1 - x, -y, -z), respectively.
	Fig. 4. The crystal packing of the title compound along a crystal axis. Hydrogen bonds are shown as dashed lines.
	Fig. 5. A perspective view of the water cluster arranged in the structure.

catena-Poly[[[aquacadmium(II)]bis(µ-4-hydroxypyridine-2,6- dicarboxylato)[aquacadmium(II)]di-µ-aqua] tetrahydrate] top

Crystal data top

[Cd₂(C₇H₃NO₅)₂(H₂O)₄]·4H₂O	Z = 2
M_r = 731.14	F(000) = 720
Triclinic, P1	D_x = 2.223 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.4499 (6) Å	Cell parameters from 1712 reflections
b = 10.8633 (7) Å	θ = 2.3–26.6°
c = 11.2086 (9) Å	µ = 2.04 mm⁻¹
α = 87.910 (3)°	T = 100 K
β = 74.239 (2)°	Prism, colourless
γ = 80.478 (2)°	0.15 × 0.12 × 0.08 mm
V = 1092.08 (13) Å³

Data collection top

Bruker SMART APEXII diffractometer	6313 independent reflections
Radiation source: fine-focus sealed tube	4460 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.060
ϕ and ω scans	θ_max = 30.1°, θ_min = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −13→13
T_min = 0.749, T_max = 0.854	k = −15→15
14393 measured reflections	l = −15→15

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.052	Hydrogen site location: mixed
wR(F²) = 0.091	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.020P)² + 3.P] where P = (F_o² + 2F_c²)/3
6313 reflections	(Δ/σ)_max < 0.001
265 parameters	Δρ_max = 1.03 e Å⁻³
0 restraints	Δρ_min = −1.01 e Å⁻³

Crystal data top

[Cd₂(C₇H₃NO₅)₂(H₂O)₄]·4H₂O	γ = 80.478 (2)°
M_r = 731.14	V = 1092.08 (13) Å³
Triclinic, P1	Z = 2
a = 9.4499 (6) Å	Mo Kα radiation
b = 10.8633 (7) Å	µ = 2.04 mm⁻¹
c = 11.2086 (9) Å	T = 100 K
α = 87.910 (3)°	0.15 × 0.12 × 0.08 mm
β = 74.239 (2)°

Data collection top

Bruker SMART APEXII diffractometer	6313 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2001)	4460 reflections with I > 2σ(I)
T_min = 0.749, T_max = 0.854	R_int = 0.060
14393 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.052	0 restraints
wR(F²) = 0.091	H-atom parameters constrained
S = 1.00	Δρ_max = 1.03 e Å⁻³
6313 reflections	Δρ_min = −1.01 e Å⁻³
265 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
Cd1	0.52233 (4)	0.41267 (3)	0.34288 (3)	0.01222 (9)
Cd2	0.64542 (4)	0.07117 (3)	0.36831 (3)	0.01104 (9)
O1	0.7671 (4)	0.7051 (4)	0.4236 (3)	0.0213 (9)
O2	0.6031 (4)	0.5739 (3)	0.4480 (3)	0.0148 (8)
O3	0.9775 (4)	0.7024 (3)	−0.0481 (3)	0.0161 (8)
H3O	0.9961	0.7687	−0.0219	0.019*
O4	0.6494 (4)	0.3865 (3)	−0.0651 (3)	0.0176 (8)
O5	0.5617 (4)	0.3419 (3)	0.1337 (3)	0.0168 (8)
O6	0.3269 (5)	0.5374 (4)	0.2974 (4)	0.0362 (12)
H6A	0.3554	0.5447	0.2191	0.043*
H6B	0.2343	0.5340	0.3225	0.043*
O7	0.4213 (4)	0.2185 (3)	0.3620 (3)	0.0125 (7)
H7A	0.3838	0.2156	0.3015	0.015*
H7B	0.3509	0.2240	0.4284	0.015*
O8	0.6944 (4)	0.2700 (3)	0.4137 (3)	0.0131 (7)
H8A	0.6943	0.2618	0.4894	0.016*
H8B	0.7838	0.2795	0.3789	0.016*
O9	0.8938 (4)	0.1332 (3)	−0.0142 (3)	0.0154 (7)
O10	0.8252 (4)	0.1290 (4)	0.1920 (3)	0.0189 (8)
O11	0.6211 (4)	−0.1986 (3)	−0.1198 (3)	0.0154 (8)
H11O	0.5712	−0.2583	−0.1067	0.018*
O12	0.3580 (4)	−0.2089 (3)	0.3456 (3)	0.0146 (7)
O13	0.4717 (4)	−0.0785 (3)	0.4216 (3)	0.0141 (7)
O14	0.8487 (4)	−0.0278 (4)	0.4192 (4)	0.0261 (9)
H14A	0.9137	−0.0794	0.3697	0.031*
H14B	0.8540	−0.0580	0.4892	0.031*
N1	0.6853 (5)	0.5189 (4)	0.2066 (4)	0.0119 (4)
N2	0.6319 (4)	−0.0249 (4)	0.1969 (4)	0.0104 (4)
C1	0.7505 (5)	0.6044 (5)	0.2457 (4)	0.0119 (4)
C2	0.8515 (5)	0.6687 (4)	0.1641 (4)	0.0119 (4)
H2A	0.8979	0.7272	0.1945	0.014*
C3	0.8838 (5)	0.6462 (5)	0.0370 (4)	0.0119 (4)
C4	0.8116 (5)	0.5594 (4)	−0.0030 (4)	0.0119 (4)
H4A	0.8286	0.5436	−0.0890	0.014*
C5	0.7155 (5)	0.4969 (4)	0.0840 (4)	0.0119 (4)
C6	0.7047 (6)	0.6299 (5)	0.3840 (5)	0.0149 (10)
C7	0.6364 (5)	0.4018 (5)	0.0464 (4)	0.0107 (9)
C8	0.7203 (5)	−0.0014 (4)	0.0849 (4)	0.0104 (4)
C9	0.7187 (5)	−0.0582 (4)	−0.0220 (4)	0.0104 (4)
H9A	0.7824	−0.0395	−0.0996	0.012*
C10	0.6223 (5)	−0.1432 (4)	−0.0149 (4)	0.0104 (4)
C11	0.5281 (5)	−0.1673 (4)	0.1005 (4)	0.0104 (4)
H11A	0.4595	−0.2238	0.1076	0.012*
C12	0.5376 (5)	−0.1068 (4)	0.2040 (4)	0.0104 (4)
C13	0.8203 (6)	0.0931 (5)	0.0898 (5)	0.0121 (10)
C14	0.4476 (6)	−0.1331 (5)	0.3343 (4)	0.0113 (10)
O15	0.9715 (4)	0.3122 (4)	0.3047 (3)	0.0203 (8)
H15A	0.9866	0.3760	0.3381	0.024*
H15B	0.9582	0.3302	0.2337	0.024*
O16	0.1500 (5)	0.0936 (4)	0.3498 (4)	0.0355 (11)
H16A	0.0945	0.0451	0.3354	0.043*
H16B	0.1150	0.1647	0.3267	0.043*
O17	0.0340 (6)	0.5346 (5)	0.3824 (6)	0.0617 (17)
H17A	−0.0011	0.5732	0.3266	0.074*
H17B	0.0098	0.5884	0.4407	0.074*
O18	0.1026 (5)	0.8506 (6)	0.2576 (4)	0.0601 (18)
H18A	0.1070	0.8458	0.1811	0.072*
H18B	0.1561	0.7904	0.2832	0.072*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.0173 (2)	0.0132 (2)	0.00806 (18)	−0.00777 (16)	−0.00365 (15)	0.00109 (14)
Cd2	0.01285 (19)	0.01276 (19)	0.00844 (18)	−0.00532 (15)	−0.00244 (15)	−0.00044 (14)
O1	0.031 (2)	0.028 (2)	0.0082 (17)	−0.0200 (18)	−0.0008 (16)	−0.0055 (15)
O2	0.0185 (19)	0.0151 (19)	0.0115 (18)	−0.0074 (15)	−0.0024 (15)	−0.0002 (14)
O3	0.0175 (19)	0.0163 (19)	0.0130 (18)	−0.0089 (15)	0.0024 (15)	−0.0004 (14)
O4	0.027 (2)	0.019 (2)	0.0095 (17)	−0.0118 (16)	−0.0043 (15)	0.0014 (14)
O5	0.026 (2)	0.0194 (19)	0.0077 (17)	−0.0168 (16)	−0.0011 (15)	0.0009 (14)
O6	0.025 (2)	0.063 (3)	0.013 (2)	0.016 (2)	−0.0060 (18)	−0.002 (2)
O7	0.0106 (17)	0.0196 (19)	0.0072 (16)	−0.0046 (14)	−0.0003 (13)	−0.0022 (13)
O8	0.0149 (18)	0.0188 (19)	0.0068 (16)	−0.0053 (14)	−0.0036 (14)	0.0015 (13)
O9	0.0179 (19)	0.0188 (19)	0.0115 (17)	−0.0097 (15)	−0.0034 (14)	0.0001 (14)
O10	0.025 (2)	0.025 (2)	0.0087 (17)	−0.0142 (17)	−0.0024 (15)	−0.0027 (15)
O11	0.022 (2)	0.0192 (19)	0.0074 (16)	−0.0142 (15)	−0.0021 (14)	−0.0031 (14)
O12	0.022 (2)	0.0134 (18)	0.0091 (17)	−0.0050 (15)	−0.0028 (15)	−0.0040 (13)
O13	0.0194 (19)	0.0139 (18)	0.0114 (17)	−0.0098 (15)	−0.0038 (15)	−0.0016 (14)
O14	0.027 (2)	0.032 (2)	0.018 (2)	−0.0006 (19)	−0.0072 (18)	0.0077 (17)
N1	0.0120 (10)	0.0121 (10)	0.0104 (9)	−0.0027 (7)	−0.0003 (7)	−0.0008 (7)
N2	0.0103 (9)	0.0122 (10)	0.0084 (9)	−0.0023 (7)	−0.0017 (7)	0.0000 (7)
C1	0.0120 (10)	0.0121 (10)	0.0104 (9)	−0.0027 (7)	−0.0003 (7)	−0.0008 (7)
C2	0.0120 (10)	0.0121 (10)	0.0104 (9)	−0.0027 (7)	−0.0003 (7)	−0.0008 (7)
C3	0.0120 (10)	0.0121 (10)	0.0104 (9)	−0.0027 (7)	−0.0003 (7)	−0.0008 (7)
C4	0.0120 (10)	0.0121 (10)	0.0104 (9)	−0.0027 (7)	−0.0003 (7)	−0.0008 (7)
C5	0.0120 (10)	0.0121 (10)	0.0104 (9)	−0.0027 (7)	−0.0003 (7)	−0.0008 (7)
C6	0.016 (3)	0.010 (2)	0.017 (3)	−0.004 (2)	0.000 (2)	−0.0035 (19)
C7	0.007 (2)	0.014 (2)	0.010 (2)	−0.0031 (18)	0.0009 (18)	−0.0028 (18)
C8	0.0103 (9)	0.0122 (10)	0.0084 (9)	−0.0023 (7)	−0.0017 (7)	0.0000 (7)
C9	0.0103 (9)	0.0122 (10)	0.0084 (9)	−0.0023 (7)	−0.0017 (7)	0.0000 (7)
C10	0.0103 (9)	0.0122 (10)	0.0084 (9)	−0.0023 (7)	−0.0017 (7)	0.0000 (7)
C11	0.0103 (9)	0.0122 (10)	0.0084 (9)	−0.0023 (7)	−0.0017 (7)	0.0000 (7)
C12	0.0103 (9)	0.0122 (10)	0.0084 (9)	−0.0023 (7)	−0.0017 (7)	0.0000 (7)
C13	0.013 (2)	0.013 (2)	0.014 (2)	−0.0096 (19)	−0.0051 (19)	0.0017 (18)
C14	0.013 (2)	0.011 (2)	0.011 (2)	−0.0052 (19)	−0.0050 (19)	0.0063 (18)
O15	0.0175 (19)	0.033 (2)	0.0114 (18)	−0.0112 (17)	−0.0013 (15)	−0.0039 (16)
O16	0.052 (3)	0.037 (3)	0.018 (2)	−0.012 (2)	−0.009 (2)	0.0051 (19)
O17	0.036 (3)	0.055 (4)	0.098 (5)	0.003 (3)	−0.026 (3)	−0.040 (3)
O18	0.031 (3)	0.127 (5)	0.012 (2)	0.029 (3)	−0.011 (2)	−0.013 (3)

Geometric parameters (Å, º) top

Cd1—O6	2.267 (4)	O13—C14	1.252 (6)
Cd1—N1	2.284 (4)	O13—Cd2ⁱⁱ	2.312 (3)
Cd1—O2ⁱ	2.320 (3)	O14—H14A	0.8500
Cd1—O8	2.335 (3)	O14—H14B	0.8500
Cd1—O5	2.406 (3)	N1—C1	1.343 (6)
Cd1—O7	2.435 (3)	N1—C5	1.347 (6)
Cd1—O2	2.474 (3)	N2—C12	1.346 (6)
Cd2—O14	2.244 (4)	N2—C8	1.347 (6)
Cd2—N2	2.263 (4)	C1—C2	1.390 (7)
Cd2—O13ⁱⁱ	2.312 (3)	C1—C6	1.515 (7)
Cd2—O10	2.372 (4)	C2—C3	1.395 (7)
Cd2—O8	2.383 (3)	C2—H2A	0.9500
Cd2—O13	2.445 (3)	C3—C4	1.402 (7)
Cd2—O7	2.450 (3)	C4—C5	1.383 (7)
O1—C6	1.241 (6)	C4—H4A	0.9500
O2—C6	1.262 (6)	C5—C7	1.505 (7)
O2—Cd1ⁱ	2.320 (3)	C8—C9	1.373 (6)
O3—C3	1.320 (5)	C8—C13	1.518 (6)
O3—H3O	0.8500	C9—C10	1.387 (6)
O4—C7	1.237 (6)	C9—H9A	0.9500
O5—C7	1.269 (6)	C10—C11	1.400 (6)
O6—H6A	0.8500	C11—C12	1.385 (6)
O6—H6B	0.8500	C11—H11A	0.9500
O7—H7A	0.8501	C12—C14	1.521 (7)
O7—H7B	0.8500	O15—H15A	0.8500
O8—H8A	0.8500	O15—H15B	0.8500
O8—H8B	0.8500	O16—H16A	0.8500
O9—C13	1.286 (6)	O16—H16B	0.8500
O10—C13	1.238 (6)	O17—H17A	0.8499
O11—C10	1.344 (5)	O17—H17B	0.8501
O11—H11O	0.8500	O18—H18A	0.8500
O12—C14	1.255 (6)	O18—H18B	0.8500

O6—Cd1—N1	90.59 (16)	H8A—O8—H8B	102.3
O6—Cd1—O2ⁱ	90.18 (14)	C13—O10—Cd2	116.8 (3)
N1—Cd1—O2ⁱ	136.84 (13)	C10—O11—H11O	113.0
O6—Cd1—O8	170.72 (15)	C14—O13—Cd2ⁱⁱ	131.0 (3)
N1—Cd1—O8	98.66 (13)	C14—O13—Cd2	117.7 (3)
O2ⁱ—Cd1—O8	82.57 (12)	Cd2ⁱⁱ—O13—Cd2	110.75 (13)
O6—Cd1—O5	81.50 (14)	Cd2—O14—H14A	121.4
N1—Cd1—O5	69.20 (13)	Cd2—O14—H14B	127.6
O2ⁱ—Cd1—O5	153.07 (12)	H14A—O14—H14B	101.5
O8—Cd1—O5	102.43 (12)	C1—N1—C5	118.9 (4)
O6—Cd1—O7	97.28 (15)	C1—N1—Cd1	121.5 (3)
N1—Cd1—O7	141.26 (13)	C5—N1—Cd1	119.6 (3)
O2ⁱ—Cd1—O7	81.24 (11)	C12—N2—C8	118.6 (4)
O8—Cd1—O7	75.95 (12)	C12—N2—Cd2	121.3 (3)
O5—Cd1—O7	74.55 (11)	C8—N2—Cd2	120.1 (3)
O6—Cd1—O2	96.88 (15)	N1—C1—C2	122.2 (4)
N1—Cd1—O2	67.99 (13)	N1—C1—C6	116.1 (4)
O2ⁱ—Cd1—O2	69.08 (14)	C2—C1—C6	121.6 (4)
O8—Cd1—O2	85.97 (12)	C1—C2—C3	119.2 (5)
O5—Cd1—O2	137.14 (11)	C1—C2—H2A	120.4
O7—Cd1—O2	147.01 (11)	C3—C2—H2A	120.4
O14—Cd2—N2	107.13 (15)	O3—C3—C2	124.0 (4)
O14—Cd2—O13ⁱⁱ	86.47 (13)	O3—C3—C4	117.9 (4)
N2—Cd2—O13ⁱⁱ	137.82 (13)	C2—C3—C4	118.1 (4)
O14—Cd2—O10	82.66 (14)	C5—C4—C3	119.3 (4)
N2—Cd2—O10	70.05 (13)	C5—C4—H4A	120.4
O13ⁱⁱ—Cd2—O10	152.13 (12)	C3—C4—H4A	120.4
O14—Cd2—O8	91.90 (13)	N1—C5—C4	122.2 (5)
N2—Cd2—O8	135.50 (13)	N1—C5—C7	116.2 (4)
O13ⁱⁱ—Cd2—O8	81.67 (12)	C4—C5—C7	121.5 (4)
O10—Cd2—O8	73.16 (12)	O1—C6—O2	126.1 (5)
O14—Cd2—O13	103.58 (13)	O1—C6—C1	117.7 (4)
N2—Cd2—O13	68.77 (13)	O2—C6—C1	116.2 (4)
O13ⁱⁱ—Cd2—O13	69.25 (13)	O4—C7—O5	125.0 (5)
O10—Cd2—O13	138.33 (12)	O4—C7—C5	118.8 (4)
O8—Cd2—O13	145.76 (12)	O5—C7—C5	116.2 (4)
O14—Cd2—O7	163.49 (13)	N2—C8—C9	122.7 (4)
N2—Cd2—O7	89.32 (13)	N2—C8—C13	113.3 (4)
O13ⁱⁱ—Cd2—O7	82.00 (12)	C9—C8—C13	124.1 (4)
O10—Cd2—O7	102.26 (12)	C8—C9—C10	118.8 (4)
O8—Cd2—O7	74.81 (11)	C8—C9—H9A	120.6
O13—Cd2—O7	83.36 (12)	C10—C9—H9A	120.6
C6—O2—Cd1ⁱ	131.4 (3)	O11—C10—C9	118.6 (4)
C6—O2—Cd1	117.6 (3)	O11—C10—C11	122.2 (4)
Cd1ⁱ—O2—Cd1	110.92 (14)	C9—C10—C11	119.2 (4)
C3—O3—H3O	113.4	C12—C11—C10	118.3 (4)
C7—O5—Cd1	118.0 (3)	C12—C11—H11A	120.9
Cd1—O6—H6A	103.6	C10—C11—H11A	120.9
Cd1—O6—H6B	129.8	N2—C12—C11	122.3 (4)
H6A—O6—H6B	111.7	N2—C12—C14	115.4 (4)
Cd1—O7—Cd2	99.37 (12)	C11—C12—C14	122.2 (4)
Cd1—O7—H7A	106.8	O10—C13—O9	123.6 (4)
Cd2—O7—H7A	119.4	O10—C13—C8	119.1 (4)
Cd1—O7—H7B	107.0	O9—C13—C8	117.3 (4)
Cd2—O7—H7B	115.1	O13—C14—O12	125.6 (5)
H7A—O7—H7B	107.9	O13—C14—C12	116.7 (4)
Cd1—O8—Cd2	104.26 (13)	O12—C14—C12	117.6 (4)
Cd1—O8—H8A	124.0	H15A—O15—H15B	110.3
Cd2—O8—H8A	101.5	H16A—O16—H16B	104.2
Cd1—O8—H8B	112.2	H17A—O17—H17B	102.7
Cd2—O8—H8B	112.2	H18A—O18—H18B	114.0

O6—Cd1—O2—C6	−94.9 (4)	O13ⁱⁱ—Cd2—N2—C12	−2.7 (5)
N1—Cd1—O2—C6	−7.1 (4)	O10—Cd2—N2—C12	176.7 (4)
O2ⁱ—Cd1—O2—C6	177.6 (5)	O8—Cd2—N2—C12	−147.3 (3)
O8—Cd1—O2—C6	94.0 (4)	O13—Cd2—N2—C12	3.2 (3)
O5—Cd1—O2—C6	−10.0 (5)	O7—Cd2—N2—C12	−79.9 (4)
O7—Cd1—O2—C6	150.2 (3)	O14—Cd2—N2—C8	−78.0 (4)
O6—Cd1—O2—Cd1ⁱ	87.55 (17)	O13ⁱⁱ—Cd2—N2—C8	177.9 (3)
N1—Cd1—O2—Cd1ⁱ	175.4 (2)	O10—Cd2—N2—C8	−2.7 (3)
O2ⁱ—Cd1—O2—Cd1ⁱ	0.0	O8—Cd2—N2—C8	33.3 (4)
O8—Cd1—O2—Cd1ⁱ	−83.58 (15)	O13—Cd2—N2—C8	−176.2 (4)
O5—Cd1—O2—Cd1ⁱ	172.46 (14)	O7—Cd2—N2—C8	100.6 (4)
O7—Cd1—O2—Cd1ⁱ	−27.3 (3)	C5—N1—C1—C2	−1.8 (7)
O6—Cd1—O5—C7	86.1 (4)	Cd1—N1—C1—C2	179.1 (4)
N1—Cd1—O5—C7	−7.8 (3)	C5—N1—C1—C6	176.5 (4)
O2ⁱ—Cd1—O5—C7	159.4 (3)	Cd1—N1—C1—C6	−2.5 (6)
O8—Cd1—O5—C7	−102.5 (4)	N1—C1—C2—C3	1.6 (8)
O7—Cd1—O5—C7	−173.9 (4)	C6—C1—C2—C3	−176.6 (5)
O2—Cd1—O5—C7	−4.9 (5)	C1—C2—C3—O3	179.8 (4)
O6—Cd1—O7—Cd2	168.82 (13)	C1—C2—C3—C4	0.3 (7)
N1—Cd1—O7—Cd2	68.7 (2)	O3—C3—C4—C5	178.5 (4)
O2ⁱ—Cd1—O7—Cd2	−102.13 (13)	C2—C3—C4—C5	−1.9 (7)
O8—Cd1—O7—Cd2	−17.66 (11)	C1—N1—C5—C4	0.1 (7)
O5—Cd1—O7—Cd2	89.76 (13)	Cd1—N1—C5—C4	179.2 (4)
O2—Cd1—O7—Cd2	−76.4 (2)	C1—N1—C5—C7	−178.9 (4)
O14—Cd2—O7—Cd1	54.7 (5)	Cd1—N1—C5—C7	0.2 (6)
N2—Cd2—O7—Cd1	−120.54 (14)	C3—C4—C5—N1	1.8 (8)
O13ⁱⁱ—Cd2—O7—Cd1	100.87 (13)	C3—C4—C5—C7	−179.3 (4)
O10—Cd2—O7—Cd1	−51.13 (13)	Cd1ⁱ—O2—C6—O1	3.4 (8)
O8—Cd2—O7—Cd1	17.39 (11)	Cd1—O2—C6—O1	−173.5 (4)
O13—Cd2—O7—Cd1	170.76 (12)	Cd1ⁱ—O2—C6—C1	−174.8 (3)
N1—Cd1—O8—Cd2	−122.31 (14)	Cd1—O2—C6—C1	8.2 (6)
O2ⁱ—Cd1—O8—Cd2	101.29 (14)	N1—C1—C6—O1	177.4 (5)
O5—Cd1—O8—Cd2	−51.83 (14)	C2—C1—C6—O1	−4.2 (8)
O7—Cd1—O8—Cd2	18.52 (11)	N1—C1—C6—O2	−4.2 (7)
O2—Cd1—O8—Cd2	170.69 (14)	C2—C1—C6—O2	174.2 (5)
O14—Cd2—O8—Cd1	171.44 (14)	Cd1—O5—C7—O4	−170.3 (4)
N2—Cd2—O8—Cd1	54.4 (2)	Cd1—O5—C7—C5	10.5 (6)
O13ⁱⁱ—Cd2—O8—Cd1	−102.41 (14)	N1—C5—C7—O4	173.4 (5)
O10—Cd2—O8—Cd1	89.69 (15)	C4—C5—C7—O4	−5.6 (7)
O13—Cd2—O8—Cd1	−70.8 (2)	N1—C5—C7—O5	−7.4 (7)
O7—Cd2—O8—Cd1	−18.49 (11)	C4—C5—C7—O5	173.7 (5)
O14—Cd2—O10—C13	118.3 (4)	C12—N2—C8—C9	−0.4 (7)
N2—Cd2—O10—C13	7.0 (4)	Cd2—N2—C8—C9	179.0 (4)
O13ⁱⁱ—Cd2—O10—C13	−173.8 (3)	C12—N2—C8—C13	179.6 (4)
O8—Cd2—O10—C13	−147.5 (4)	Cd2—N2—C8—C13	−1.0 (5)
O13—Cd2—O10—C13	16.1 (5)	N2—C8—C9—C10	0.0 (7)
O7—Cd2—O10—C13	−77.7 (4)	C13—C8—C9—C10	180.0 (4)
O14—Cd2—O13—C14	−107.3 (4)	C8—C9—C10—O11	−180.0 (4)
N2—Cd2—O13—C14	−3.9 (4)	C8—C9—C10—C11	1.0 (7)
O13ⁱⁱ—Cd2—O13—C14	171.9 (5)	O11—C10—C11—C12	179.5 (4)
O10—Cd2—O13—C14	−13.1 (5)	C9—C10—C11—C12	−1.4 (7)
O8—Cd2—O13—C14	138.2 (3)	C8—N2—C12—C11	−0.1 (7)
O7—Cd2—O13—C14	87.9 (4)	Cd2—N2—C12—C11	−179.6 (4)
O14—Cd2—O13—Cd2ⁱⁱ	80.84 (17)	C8—N2—C12—C14	177.0 (4)
N2—Cd2—O13—Cd2ⁱⁱ	−175.8 (2)	Cd2—N2—C12—C14	−2.5 (6)
O13ⁱⁱ—Cd2—O13—Cd2ⁱⁱ	0.0	C10—C11—C12—N2	1.0 (7)
O10—Cd2—O13—Cd2ⁱⁱ	175.07 (15)	C10—C11—C12—C14	−175.9 (4)
O8—Cd2—O13—Cd2ⁱⁱ	−33.7 (3)	Cd2—O10—C13—O9	168.5 (4)
O7—Cd2—O13—Cd2ⁱⁱ	−83.93 (15)	Cd2—O10—C13—C8	−10.2 (6)
O6—Cd1—N1—C1	101.9 (4)	N2—C8—C13—O10	7.7 (7)
O2ⁱ—Cd1—N1—C1	11.0 (5)	C9—C8—C13—O10	−172.3 (5)
O8—Cd1—N1—C1	−77.4 (4)	N2—C8—C13—O9	−171.1 (4)
O5—Cd1—N1—C1	−177.5 (4)	C9—C8—C13—O9	8.9 (7)
O7—Cd1—N1—C1	−155.7 (3)	Cd2ⁱⁱ—O13—C14—O12	−7.4 (8)
O2—Cd1—N1—C1	4.7 (4)	Cd2—O13—C14—O12	−177.3 (4)
O6—Cd1—N1—C5	−77.2 (4)	Cd2ⁱⁱ—O13—C14—C12	174.0 (3)
O2ⁱ—Cd1—N1—C5	−168.1 (3)	Cd2—O13—C14—C12	4.1 (6)
O8—Cd1—N1—C5	103.6 (4)	N2—C12—C14—O13	−1.3 (7)
O5—Cd1—N1—C5	3.5 (3)	C11—C12—C14—O13	175.8 (5)
O7—Cd1—N1—C5	25.2 (5)	N2—C12—C14—O12	180.0 (4)
O2—Cd1—N1—C5	−174.4 (4)	C11—C12—C14—O12	−2.9 (7)
O14—Cd2—N2—C12	101.5 (4)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3O···O9ⁱⁱⁱ	0.85	1.74	2.536 (5)	156
O6—H6A···O4^iv	0.85	1.87	2.665 (5)	156
O6—H6B···O17	0.85	1.83	2.677 (8)	177
O7—H7A···O11^v	0.85	2.07	2.871 (5)	158
O7—H7B···O1ⁱ	0.85	1.84	2.639 (5)	156
O8—H8A···O12ⁱⁱ	0.85	1.88	2.687 (5)	159
O8—H8B···O15	0.85	1.83	2.679 (5)	176
O11—H11O···O5^v	0.85	1.76	2.547 (5)	153
O14—H14A···O18^vi	0.85	1.94	2.747 (7)	159
O14—H14B···O16ⁱⁱ	0.85	1.82	2.663 (6)	169
O15—H15A···O17^vii	0.85	1.96	2.802 (7)	169
O15—H15B···O3ⁱⁱⁱ	0.85	2.03	2.790 (5)	149
O16—H16A···O18^viii	0.85	2.30	3.013 (6)	142
O16—H16A···O14^ix	0.85	2.51	3.228 (6)	143
O16—H16B···O15^ix	0.85	1.97	2.791 (6)	161
O18—H18A···O9^iv	0.85	1.88	2.719 (5)	170
O18—H18B···O12^x	0.85	2.20	2.819 (6)	129
C11—H11A···O4^v	0.95	2.31	3.224 (6)	161

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y, −z+1; (iii) −x+2, −y+1, −z; (iv) −x+1, −y+1, −z; (v) −x+1, −y, −z; (vi) x+1, y−1, z; (vii) x+1, y, z; (viii) x, y−1, z; (ix) x−1, y, z; (x) x, y+1, z.

Experimental details

Crystal data
Chemical formula	[Cd₂(C₇H₃NO₅)₂(H₂O)₄]·4H₂O
M_r	731.14
Crystal system, space group	Triclinic, P1
Temperature (K)	100
a, b, c (Å)	9.4499 (6), 10.8633 (7), 11.2086 (9)
α, β, γ (°)	87.910 (3), 74.239 (2), 80.478 (2)
V (Å³)	1092.08 (13)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	2.04
Crystal size (mm)	0.15 × 0.12 × 0.08

Data collection
Diffractometer	Bruker SMART APEXII diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.749, 0.854
No. of measured, independent and observed [I > 2σ(I)] reflections	14393, 6313, 4460
R_int	0.060
(sin θ/λ)_max (Å⁻¹)	0.705

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.052, 0.091, 1.00
No. of reflections	6313
No. of parameters	265
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.03, −1.01

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3O···O9ⁱ	0.850	1.735	2.536 (5)	156
O6—H6A···O4ⁱⁱ	0.850	1.865	2.665 (5)	156
O6—H6B···O17	0.850	1.828	2.677 (8)	177
O7—H7A···O11ⁱⁱⁱ	0.850	2.065	2.871 (5)	158
O7—H7B···O1^iv	0.850	1.841	2.639 (5)	156
O8—H8A···O12^v	0.850	1.875	2.687 (5)	159
O8—H8B···O15	0.850	1.830	2.679 (5)	176
O11—H11O···O5ⁱⁱⁱ	0.850	1.760	2.547 (5)	153
O14—H14A···O18^vi	0.850	1.935	2.747 (7)	159
O14—H14B···O16^v	0.850	1.823	2.663 (6)	169
O15—H15A···O17^vii	0.850	1.963	2.802 (7)	169
O15—H15B···O3ⁱ	0.850	2.029	2.790 (5)	149
O16—H16A···O18^viii	0.850	2.297	3.013 (6)	142
O16—H16A···O14^ix	0.850	2.505	3.228 (6)	143
O16—H16B···O15^ix	0.850	1.974	2.791 (6)	161
O18—H18A···O9ⁱⁱ	0.850	1.879	2.719 (5)	170
O18—H18B···O12^x	0.850	2.204	2.819 (6)	129
C11—H11A···O4ⁱⁱⁱ	0.950	2.310	3.224 (6)	161

Symmetry codes: (i) −x+2, −y+1, −z; (ii) −x+1, −y+1, −z; (iii) −x+1, −y, −z; (iv) −x+1, −y+1, −z+1; (v) −x+1, −y, −z+1; (vi) x+1, y−1, z; (vii) x+1, y, z; (viii) x, y−1, z; (ix) x−1, y, z; (x) x, y+1, z.

Cd—O and Cd—N distances in comparable compounds top

Compound	Coordination No.	Cd—O bond length (Å)	Cd—N bond length (Å)
(enH₂)₂[Cd(pydc)₃]^.6H₂O, 1 (Fu et al., 2004)	9	2.522, 2.541, 2.567	2.397, 2.419
[Cd₂(pydc)₂(H₂O)₆]^.2pydcH₂, 2 (Odoko et al., 2002)	7	2.376, 2.396	2.478, 2.315
[Cd₂(pydc)₂(CH₃OH)₂(H₂O)]_n, 3 (Wu et al., 2007)	7	2.326, 2.331, 2.376, 2.464	2.319
Cd(pydc)(H₂O)₃]₂^.2H₂pydc, 4 (Ranjbar et al., 2002)	7	2.367, 2.390, 2.453	2.321
[Cd(py-2,3-dc)(H₂O)₃]_n, 5 (Aghabozorg, Motyeian et al., 2008)	6	2.259, 2.279	2.302

Cd—O bonds of coordinated water molecules are not considered.

References

Aghabozorg, H., Ghadermazi, M., Soleimannejad, J. & Sheshmani, S. (2007). Acta Cryst. E63, m1917–m1918. Web of Science CSD CrossRef IUCr Journals Google Scholar
Aghabozorg, H., Manteghi, F. & Sheshmani, S. (2008). J. Iran. Chem. Soc. 5, 184–227. CrossRef CAS Google Scholar
Aghabozorg, H., Motyeian, E., Khadivi, R., Ghadermazi, M. & Manteghi, F. (2008). Acta Cryst. E64, m320–m321. Web of Science CSD CrossRef IUCr Journals Google Scholar
Aghabozorg, H., Roshan, L., Firoozi, N., Ghadermazi, M. & Bagheri, S. (2008). Acta Cryst. E64, m1208–m1209. Web of Science CSD CrossRef IUCr Journals Google Scholar
Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Fu, A.-Y., Wang, D.-Q. & Liu, A.-Z. (2004). Acta Cryst. E60, m1372–m1373. Web of Science CSD CrossRef IUCr Journals Google Scholar
Ghosh, S. K., Ribas, J., El Fallah, M. S. & Bharadwaj, P. K. (2005). Inorg. Chem. 44, 3856–3862. Web of Science CSD CrossRef PubMed CAS Google Scholar
Odoko, M., Kusano, A. & Okabe, N. (2002). Acta Cryst. E58, m25–m27. Web of Science CSD CrossRef IUCr Journals Google Scholar
Ranjbar, M., Aghabozorg, H. & Moghimi, A. (2002). Acta Cryst. E58, m304–m306. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wu, H.-F., Chen, X.-D. & Du, M. (2007). Acta Cryst. E63, m126–m128. Web of Science CSD CrossRef IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.