catena-Poly[hexa­aqua­magnesium(II) [bis­(μ₃-5-nitro-2-oxidoisophthalato)dicopper(II)] dihydrate]

In the centrosymmetric dinuclear anions of the title bimetallic complex, {[Mg(H₂O)₆][Cu₂(C₈H₂NO₇)₂]·2H₂O}_n, each Cu^II ion is strongly coordinated by four O atoms in a distorted square-planar geometry. Two of these O atoms belong to phenolate groups and the other two to carboxyl­ate groups from 5-nitro-2-oxidoisophthalate (L1) trianions, derived from 5-nitro­benzene-1,2,3-tricarb­oxy­lic acid (O₂N–H₃L). The phenolate O atoms bridge the two Cu^II ions in the anion. In addition, each Cu^II cation inter­acts weakly with a symmetry-related carboxyl­ate O atom of an adjacent L1 ligand, giving a square-pyramidal coordination geometry. The copper residue forms a ladder-like linear coordination polymer via L1 ligands. The [Mg(H₂O)₆]²⁺ cations sit on centres of inversion. The polymeric anions, cations and free water mol­ecules are self-assembled into a three-dimensional supra­molecular network via O—H...O hydrogen bonds.

S1. Comment

The current great interest in the design and construction of functional metal–organic coordination polymers stems from their potential applications in molecular adsorption, heterogeneous catalysis, ion exchange, and magnetic and photochemical areas, and is also due to the intriguing variety of topologies they display (Zhang et al., 2009; Xamena et al., 2007; An et al., 2009; Pan et al., 2008; Zheng et al., 2007; Ockwig et al., 2005). Choosing a proper multifunctional ligand to link metal cations to generate novel solid-state frameworks is of vital importance (Liu et al., 2002). Multicarboxylate ligands such as benzene-1,3-dicarboxylate, benzene-1,4-dicarboxylate and benzene-1,3,5-tricarboxylate have been widely used to construct metal–organic complexes with fascinating structures and potential applications (Zhou et al., 2004; Wen et al., 2005; Manna et al., 2007; Du et al., 2006; Ma et al., 2009). Benzene-1,2,3-tricarboxylic acid, with its particular orientation and the strong steric hindrance of the three carboxylic acid groups, could lead to novel metal–organic complexes (Zheng et al., 2004; Gutschke et al., 2001) different from those constructed by other symmetric benzenecarboxylates. From a structural point of view, 5-nitrobenzene-1,2,3-tricarboxylic acid (O₂N–H₃L) possesses two interesting characteristics: (i) as a multidentate and rigid ligand with multiproton acceptor–donor sites it might be utilized as a versatile linker to construct interesting coordination polymers with abundant hydrogen bonds and π–π stacking interactions; (ii) the carboxylate groups can display a variety of bonding geometries, such as monodentate, chelating, bidentate bridging, monodentate bridging and chelating bridging. However, to the best of our knowledge, syntheses and characterization of coordination polymers based on the O₂N–H₃L ligand are still very scarce (Tan & Yi, 2010; Ding & Zhao, 2010; Ma et al., 2010). Based on the above, we chose O₂N–H₃L as a multifunctional linker to construct the title novel metal–organic complex, {[Mg(H₂O)₆][Cu₂(L1)₂].2H₂O}_n, (I), which represents the first example of a metal-based supramolecular framework constructed from the 5-nitro-2-oxidoisophthalate trianion (L1), where L1 is derived from O₂N–H₃L.

Compound (I) was obtained under hydrothermal conditions at 433 K. Once formed, the compound is insoluble in most solvents, including water. As shown in Fig. 1, the asymmetric unit contains one Cu^II cation, one-half of an Mg^II cation, one L₁ ligand, three coordinated water molecules and one free water molecule.

As seen in Fig. 1, the Cu^II cation is primarily coordinated to four O atoms in a distorted square geometry [mean Cu—O distance = 1.91 (3) Å]. Two of these O atoms belong to two phenolate groups and the other two to carboxylate groups of two L1 ligands. In addition, the Cu^II cation interacts weakly with a symmetry-related carboxylate O atom from a third L1 ligand with a substantially longer Cu—O bond distance of 2.379 (3) Å, giving a square-pyramidal coordination geometry (Fig. 1). All Cu—O bond lengths and O—Cu—O angles are within the ranges observed in other Cu^II complexes (see, for example, Zheng et al., 2009; Wang & Wang, 2008). The L1 ligands all exhibit the same coordination mode, viz. µ₃-bridging and chelating, to link three Cu^II cations. On the basis of this, atoms Cu1 and Cu1ⁱⁱ [symmetry code: (ii) -x + 2, -y + 1, -z] form dinuclear [Cu₂(L1)₂]^2- units (Figs. 1 and 2), which are interconnected via weak Cu1···O5 interactions, resulting in one-dimensional ladder-like chains along the a axis.

The Mg^II cation, lying on an inversion centre, is surrounded by six aqua ligands [mean Mg—O distance = 2.07 (2) Å], exhibiting a slightly distorted octahedral environment. It is interesting that the [Mg(H₂O)₆]²⁺ cations and free water molecules act as bridges to connect the chains into a sandwich-like three-dimensional supramolecular structure via a wide range of O—H···O hydrogen-bonding interactions through the nitro O atoms, the coordinated and uncoordinated carboxylate O atoms from the L1 ligands, and the coordinated and free water molecules (Fig. 2 and Table 1). It is worth noting that an in situ reaction occurs in the CuBr₂.2H₂O/H₃L₁/MgCl₂ system under hydrothermal conditions. In fact, such an in situ reaction has previously been observed during the hydrothermal process (Zheng et al., 2009; Wang & Wang, 2008). However, contrary to the previous reports, Cu^I cations and insoluble cuprous oxide or other soluble cuprous compounds are not observed in compound (I). The origin of this in situ reaction is not yet clear, and a more in-depth study is required to understand the mechanisms for such a reaction.

Related literature

For related literature, see: An et al. (2009); Ding & Zhao (2010); Du et al. (2006); Gutschke et al. (2001); Liu et al. (2002); Ma et al. (2009, 2010); Manna et al. (2007); Ockwig et al. (2005); Pan et al. (2008); Tan & Yi (2010); Wang & Wang (2008); Wen et al. (2005); Xamena et al. (2007); Zhang et al. (2009); Zheng et al. (2004, 2007, 2009); Zhou et al. (2004).

S2. Experimental

A mixture of copper bromide (0.112 g, 0.5 mmol), 5-nitrobenzene-1,2,3-tricarboxylic acid (0.12 g, 0.5 mmol), magnesium chloride (0.05 g, 0.5 mmol), NaOH (0.06 g, 1.5 mmol) and H₂O (12 ml) was placed in a 23 ml Teflon reactor, which was heated to 433 K for 3 d and then cooled to room temperature at a rate of 5 K h^-1. The crystals obtained were washed with water and dried in air

S3. Refinement

Carbon-bound H atoms were placed at calculated positions and treated as riding on their parent C atoms, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C). Aqua H atoms were located in a difference Fourier map and refined as riding in their as-found relative positions, with distance restraints of O—H = 0.84 (1) Å and H···H = 1.39 (1) Å, and with U_iso(H) = 1.2U_eq(O).

Computing details

Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I), with displacement ellipsoids drawn at the 50% probability level. [Symmetry codes: (i) -x + 1, -y + 1, -z + 1; (ii) -x + 2, -y + 1, -z; (iii) -x + 1, -y + 1, -z; (iv) x + 1, y, z.]
	Fig. 2. A view of the sandwich-like three-dimensional supramolecular structure of (I), formed via a wide range of O—H···O hydrogen-bonding interactions.

catena-Poly[hexaaquamagnesium(II) [bis(µ₃-5-nitro-2-oxidoisophthalato)dicopper(II)] dihydrate]

Crystal data

[Mg(H2O)6][Cu2(C8H2NO7)2]·2H2O	Z = 1
Mr = 743.73	F(000) = 376
Triclinic, P1	Dx = 2.046 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.0936 (8) Å	Cell parameters from 1702 reflections
b = 9.8320 (13) Å	θ = 2.5–25.9°
c = 12.8114 (14) Å	µ = 1.90 mm^−1
α = 73.952 (1)°	T = 298 K
β = 78.679 (1)°	Needle, blue
γ = 83.706 (2)°	0.41 × 0.14 × 0.10 mm
V = 603.55 (14) Å^3

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	2082 independent reflections
Radiation source: fine-focus sealed tube	1799 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
ϕ and ω scans	θmax = 25.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −5→6
Tmin = 0.746, Tmax = 0.839	k = −11→10
3113 measured reflections	l = −14→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.111	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0708P)^2] where P = (Fo^2 + 2Fc^2)/3
2082 reflections	(Δ/σ)max < 0.001
196 parameters	Δρmax = 0.68 e Å^−3
0 restraints	Δρmin = −0.67 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.9547 (2)	0.51350 (10)	−0.11430 (7)	0.0189 (5)
Mg1	0.5000	0.5000	0.5000	0.0190 (9)
N1	0.1943 (16)	−0.0535 (8)	0.1871 (6)	0.0275 (18)
O1	0.8339 (12)	0.4093 (6)	0.0364 (4)	0.0186 (13)
O2	0.9433 (13)	0.3492 (6)	0.2479 (5)	0.0256 (14)
O3	0.7531 (14)	0.1650 (6)	0.3642 (5)	0.0306 (16)
O4	0.6860 (12)	0.4442 (6)	−0.1670 (4)	0.0221 (13)
O5	0.3080 (12)	0.3455 (6)	−0.1527 (5)	0.0239 (14)
O6	0.2170 (18)	−0.1335 (8)	0.2781 (6)	0.055 (2)
O7	0.0526 (17)	−0.0743 (8)	0.1284 (7)	0.048 (2)
O1W	0.7282 (13)	0.6380 (7)	0.3713 (5)	0.0281 (15)
H1W	0.7197	0.7209	0.3803	0.034*
H2W	0.7283	0.6338	0.3060	0.034*
O2W	0.6800 (12)	0.5600 (6)	0.6088 (5)	0.0256 (14)
H3W	0.8415	0.5836	0.5935	0.031*
H4W	0.6613	0.5039	0.6732	0.031*
O3W	0.8024 (12)	0.3378 (6)	0.4925 (5)	0.0249 (14)
H5W	0.7792	0.2810	0.4561	0.030*
H6W	0.8340	0.2797	0.5521	0.030*
O4W	0.7303 (15)	0.8689 (7)	0.4559 (6)	0.0447 (19)
H7W	0.6149	0.8561	0.5149	0.054*
H8W	0.7547	0.9563	0.4263	0.054*
C1	0.7947 (18)	0.2457 (9)	0.2697 (7)	0.0207 (18)
C2	0.5049 (17)	0.3587 (8)	−0.1125 (6)	0.0177 (18)
C3	0.6768 (16)	0.3013 (8)	0.0736 (6)	0.0169 (17)
C4	0.6566 (17)	0.2176 (9)	0.1838 (7)	0.0186 (18)
C5	0.4978 (18)	0.1016 (9)	0.2182 (7)	0.0216 (18)
H5	0.4878	0.0439	0.2897	0.026*
C6	0.3565 (17)	0.0714 (8)	0.1481 (7)	0.0203 (18)
C7	0.3565 (17)	0.1554 (9)	0.0424 (7)	0.0207 (18)
H7	0.2513	0.1351	−0.0024	0.025*
C8	0.5171 (17)	0.2717 (8)	0.0036 (6)	0.0174 (17)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0213 (7)	0.0231 (7)	0.0116 (6)	−0.0038 (4)	−0.0044 (4)	−0.0016 (4)
Mg1	0.018 (2)	0.025 (2)	0.0144 (19)	−0.0002 (16)	−0.0042 (16)	−0.0048 (16)
N1	0.030 (5)	0.021 (4)	0.030 (4)	−0.007 (3)	0.002 (4)	−0.007 (3)
O1	0.023 (3)	0.021 (3)	0.011 (3)	−0.005 (2)	−0.004 (2)	−0.001 (2)
O2	0.034 (4)	0.027 (3)	0.014 (3)	−0.008 (3)	−0.007 (3)	0.001 (2)
O3	0.048 (4)	0.027 (3)	0.015 (3)	−0.008 (3)	−0.009 (3)	0.002 (3)
O4	0.023 (3)	0.030 (3)	0.012 (3)	−0.007 (3)	−0.006 (2)	0.000 (2)
O5	0.024 (4)	0.030 (3)	0.018 (3)	−0.004 (3)	−0.007 (3)	−0.004 (3)
O6	0.078 (7)	0.043 (5)	0.038 (5)	−0.031 (4)	−0.014 (4)	0.013 (4)
O7	0.055 (5)	0.045 (5)	0.050 (5)	−0.023 (4)	−0.019 (4)	−0.007 (4)
O1W	0.037 (4)	0.029 (3)	0.016 (3)	−0.004 (3)	−0.002 (3)	−0.003 (3)
O2W	0.026 (4)	0.035 (4)	0.017 (3)	−0.006 (3)	−0.006 (3)	−0.003 (3)
O3W	0.027 (4)	0.027 (3)	0.021 (3)	0.006 (3)	−0.008 (3)	−0.007 (3)
O4W	0.058 (5)	0.027 (4)	0.041 (4)	0.000 (3)	0.002 (4)	−0.004 (3)
C1	0.024 (5)	0.020 (4)	0.016 (4)	0.003 (4)	−0.003 (4)	−0.004 (3)
C2	0.021 (5)	0.017 (4)	0.016 (4)	0.007 (3)	−0.005 (4)	−0.006 (3)
C3	0.015 (4)	0.017 (4)	0.016 (4)	0.001 (3)	0.002 (3)	−0.006 (3)
C4	0.020 (4)	0.017 (4)	0.017 (4)	0.002 (3)	−0.003 (3)	−0.003 (3)
C5	0.025 (5)	0.020 (4)	0.018 (4)	0.001 (3)	−0.003 (4)	−0.002 (3)
C6	0.021 (5)	0.014 (4)	0.023 (4)	−0.002 (3)	0.000 (4)	−0.002 (3)
C7	0.020 (5)	0.024 (4)	0.020 (4)	0.000 (3)	−0.005 (4)	−0.008 (4)
C8	0.020 (4)	0.019 (4)	0.013 (4)	0.002 (3)	−0.003 (3)	−0.004 (3)

Geometric parameters (Å, º)

Cu1—O2^i	1.884 (6)	O5—C2	1.247 (10)
Cu1—O4	1.902 (6)	O5—Cu1^iv	2.379 (6)
Cu1—O1	1.932 (5)	O1W—H1W	0.8500
Cu1—O1^i	1.937 (6)	O1W—H2W	0.8499
Cu1—O5^ii	2.379 (6)	O2W—H3W	0.8500
Cu1—Cu1^i	2.9889 (19)	O2W—H4W	0.8499
Mg1—O2W^iii	2.051 (6)	O3W—H5W	0.8499
Mg1—O2W	2.051 (6)	O3W—H6W	0.8499
Mg1—O1W^iii	2.065 (6)	O4W—H7W	0.8500
Mg1—O1W	2.065 (6)	O4W—H8W	0.8499
Mg1—O3W	2.101 (6)	C1—C4	1.516 (12)
Mg1—O3W^iii	2.101 (6)	C2—C8	1.507 (11)
N1—O7	1.208 (11)	C3—C4	1.414 (11)
N1—O6	1.232 (10)	C3—C8	1.425 (11)
N1—C6	1.470 (10)	C4—C5	1.391 (12)
O1—C3	1.323 (9)	C5—C6	1.363 (12)
O1—Cu1^i	1.937 (6)	C5—H5	0.9300
O2—C1	1.271 (10)	C6—C7	1.378 (11)
O2—Cu1^i	1.884 (6)	C7—C8	1.397 (11)
O3—C1	1.244 (10)	C7—H7	0.9300
O4—C2	1.279 (10)
O2^i—Cu1—O4	94.1 (3)	C2—O4—Cu1	128.6 (5)
O2^i—Cu1—O1	167.1 (2)	C2—O5—Cu1^iv	110.0 (5)
O4—Cu1—O1	92.7 (2)	Mg1—O1W—H1W	112.7
O2^i—Cu1—O1^i	92.7 (2)	Mg1—O1W—H2W	118.4
O4—Cu1—O1^i	167.8 (2)	H1W—O1W—H2W	115.6
O1—Cu1—O1^i	78.8 (3)	Mg1—O2W—H3W	122.7
O2^i—Cu1—O5^ii	94.3 (2)	Mg1—O2W—H4W	114.4
O4—Cu1—O5^ii	97.6 (2)	H3W—O2W—H4W	106.1
O1—Cu1—O5^ii	95.7 (2)	Mg1—O3W—H5W	115.2
O1^i—Cu1—O5^ii	92.0 (2)	Mg1—O3W—H6W	119.1
O2^i—Cu1—Cu1^i	131.31 (19)	H5W—O3W—H6W	100.8
O4—Cu1—Cu1^i	131.60 (18)	H7W—O4W—H8W	112.0
O1—Cu1—Cu1^i	39.48 (17)	O3—C1—O2	120.5 (8)
O1^i—Cu1—Cu1^i	39.37 (16)	O3—C1—C4	117.5 (8)
O5^ii—Cu1—Cu1^i	94.99 (15)	O2—C1—C4	122.0 (7)
O2W^iii—Mg1—O2W	180.000 (1)	O5—C2—O4	121.4 (7)
O2W^iii—Mg1—O1W^iii	89.3 (2)	O5—C2—C8	117.0 (7)
O2W—Mg1—O1W^iii	90.7 (2)	O4—C2—C8	121.6 (7)
O2W^iii—Mg1—O1W	90.7 (2)	O1—C3—C4	120.8 (7)
O2W—Mg1—O1W	89.3 (2)	O1—C3—C8	120.0 (7)
O1W^iii—Mg1—O1W	180.000 (1)	C4—C3—C8	119.1 (7)
O2W^iii—Mg1—O3W	90.7 (2)	C5—C4—C3	118.9 (8)
O2W—Mg1—O3W	89.3 (2)	C5—C4—C1	116.5 (7)
O1W^iii—Mg1—O3W	89.8 (2)	C3—C4—C1	124.6 (7)
O1W—Mg1—O3W	90.2 (2)	C6—C5—C4	120.7 (8)
O2W^iii—Mg1—O3W^iii	89.3 (2)	C6—C5—H5	119.6
O2W—Mg1—O3W^iii	90.7 (2)	C4—C5—H5	119.6
O1W^iii—Mg1—O3W^iii	90.2 (2)	C5—C6—C7	122.3 (8)
O1W—Mg1—O3W^iii	89.8 (2)	C5—C6—N1	119.0 (8)
O3W—Mg1—O3W^iii	180.000 (2)	C7—C6—N1	118.7 (8)
O7—N1—O6	123.6 (8)	C6—C7—C8	118.9 (8)
O7—N1—C6	119.2 (8)	C6—C7—H7	120.5
O6—N1—C6	117.1 (8)	C8—C7—H7	120.5
C3—O1—Cu1	128.7 (5)	C7—C8—C3	119.8 (7)
C3—O1—Cu1^i	129.6 (5)	C7—C8—C2	115.7 (7)
Cu1—O1—Cu1^i	101.2 (3)	C3—C8—C2	124.5 (7)
C1—O2—Cu1^i	130.2 (5)
O2^i—Cu1—O1—C3	138.4 (11)	O1—C3—C4—C1	3.4 (12)
O4—Cu1—O1—C3	16.9 (7)	C8—C3—C4—C1	−174.1 (7)
O1^i—Cu1—O1—C3	−172.0 (8)	O3—C1—C4—C5	−1.0 (12)
O5^ii—Cu1—O1—C3	−81.0 (7)	O2—C1—C4—C5	−179.5 (8)
Cu1^i—Cu1—O1—C3	−172.0 (8)	O3—C1—C4—C3	178.2 (8)
O2^i—Cu1—O1—Cu1^i	−49.6 (13)	O2—C1—C4—C3	−0.3 (13)
O4—Cu1—O1—Cu1^i	−171.2 (3)	C3—C4—C5—C6	−2.1 (12)
O1^i—Cu1—O1—Cu1^i	0.0	C1—C4—C5—C6	177.2 (7)
O5^ii—Cu1—O1—Cu1^i	91.0 (3)	C4—C5—C6—C7	−2.1 (13)
O2^i—Cu1—O4—C2	−169.4 (7)	C4—C5—C6—N1	179.0 (7)
O1—Cu1—O4—C2	−0.4 (7)	O7—N1—C6—C5	174.2 (8)
O1^i—Cu1—O4—C2	−46.1 (15)	O6—N1—C6—C5	−7.5 (12)
O5^ii—Cu1—O4—C2	95.7 (7)	O7—N1—C6—C7	−4.6 (12)
Cu1^i—Cu1—O4—C2	−7.9 (8)	O6—N1—C6—C7	173.6 (8)
Cu1^i—O2—C1—O3	179.3 (6)	C5—C6—C7—C8	3.2 (13)
Cu1^i—O2—C1—C4	−2.2 (12)	N1—C6—C7—C8	−177.9 (7)
Cu1^iv—O5—C2—O4	−88.7 (8)	C6—C7—C8—C3	−0.1 (12)
Cu1^iv—O5—C2—C8	90.3 (7)	C6—C7—C8—C2	−179.7 (7)
Cu1—O4—C2—O5	164.5 (6)	O1—C3—C8—C7	178.4 (7)
Cu1—O4—C2—C8	−14.3 (11)	C4—C3—C8—C7	−4.0 (11)
Cu1—O1—C3—C4	165.7 (6)	O1—C3—C8—C2	−2.0 (12)
Cu1^i—O1—C3—C4	−4.0 (11)	C4—C3—C8—C2	175.5 (7)
Cu1—O1—C3—C8	−16.8 (11)	O5—C2—C8—C7	18.7 (10)
Cu1^i—O1—C3—C8	173.5 (5)	O4—C2—C8—C7	−162.3 (7)
O1—C3—C4—C5	−177.4 (7)	O5—C2—C8—C3	−160.8 (8)
C8—C3—C4—C5	5.1 (11)	O4—C2—C8—C3	18.1 (12)

Symmetry codes: (i) −x+2, −y+1, −z; (ii) x+1, y, z; (iii) −x+1, −y+1, −z+1; (iv) x−1, y, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W···O4W	0.85	1.97	2.774 (9)	158
O1W—H2W···O5^v	0.85	1.96	2.802 (8)	170
O2W—H3W···O3W^vi	0.85	2.04	2.857 (8)	162
O2W—H4W···O4^vii	0.85	1.99	2.787 (8)	155
O3W—H5W···O3	0.85	1.88	2.728 (8)	174
O3W—H6W···O6^viii	0.85	2.24	3.058 (10)	163
O4W—H7W···O3^iii	0.85	2.17	3.002 (10)	165
O4W—H8W···O3^ix	0.85	1.99	2.829 (9)	171

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