Two new cadmium(II) coordination polymers based on bis­(1,2,4-triazol-1-yl)alkane ligands and pyrazine-2,3-di­carb­oxy­lic acid

Assemblies of pyrazine-2,3-di­carb­oxy­lic acid and Cd^II in the presence of bis­(1,2,4-triazol-1-yl)butane or bis­(1,2,4-triazol-1-yl)ethane under ambient con­ditions yielded two new coordination polymers, namely poly[[tetra­aqua­[μ₂-1,4-bis­(1,2,4-triazol-1-yl)butane-κ²N⁴:N^4′]bis­(μ₂-pyrazine-2,3-di­carboxyl­ato-κ³N¹,O²:O³)dicadmium(II)] dihydrate], {[Cd₂(C₆H₂N₂O₄)₂(C₈H₁₂N₆)(H₂O)₄]·2H₂O}_n, (I), and poly[[di­aqua­[μ₂-1,2-bis­(1,2,4-triazol-1-yl)ethane-κ²N⁴:N^4′]bis­(μ₃-pyrazine-2,3-di­carboxyl­ato-κ⁴N¹,O²:O³:O^3′)dicadmium(II)] dihydrate], {[Cd₂(C₆H₂N₂O₄)₂(C₆H₈N₆)(H₂O)₂]·2H₂O}_n, (II). Complex (I) displays an inter­esting two-dimensional wave-like structure and forms a distinct extended three-dimensional supra­molecular structure with the help of O—H...N and O—H...O hydrogen bonds. Complex (II) has a three-dimensional framework structure in which hydrogen bonds of the O—H...N and O—H...O types are found.

S1. Introduction

During the past decade, coordination polymers have attracted increased attention for their potential applications in the areas of magnetism, catalysis, adsorption and luminescence, as well as for the variety of their architectures and topologies (Rosi et al., 2003; Yaghi et al., 2003; Ockwig et al., 2005; Kitagawa et al., 2004). Although a great deal of effort has been devoted to coordination polymers, the rational design and synthesis of polymers with desired structures and properties is still a huge challenge for inorganic chemists because of the comprehensive effect of solvents, ligands, central metal atoms and organic anions (Ye et al., 2005). It has been shown that employing multi­carboxyl­ate ligands is an effective approach to synthesize such complexes, due to their strong coordination activity with metal ions, as well as their various coordination modes and versatile conformations (Zhao et al., 2003; Chen et al., 2011). As an example of a multi­carboxyl­ate ligand, pyrazine-2,3-di­carb­oxy­lic acid (H₂pzdc) has been used widely in the preparation of coordination polymers, which have exhibited one-dimensional chains, two-dimensional networks and three-dimensional frameworks (Seo et al., 2009; Yang et al., 2004; Zheng et al., 2002). On the other hand, some auxiliary ligands have often been used in order to tune the structures and properties of the complexes formed, such as 2,2'-bi­pyridine, 4,4'-bi­pyridine and 1,10-phenanthroline (Bradshaw et al., 2005; Batten & Murray, 2003). Compared with these rigid ligands, molecules with flexible –CH₂– spacers could possibly result in unpredi­cta­ble and inter­esting frameworks as they are able to bend or rotate freely to conform to the coordination geometries of metal centres (Chen et al., 1995; Li et al., 2005; Wang et al., 2005).

In this contribution, we employed bis­(1,2,4-triazol-1-yl)butane (btb) and bis­(1,2,4-triazol-1-yl)ethane (bte) as flexible auxiliary ligands to react with H₂pzdc and cadmium nitrate, and two novel cadmium complexes, {[Cd₂(pzdc)₂(btb)(H₂O)₄]·2H₂O}_n, (I) and {[Cd₂(pzdc)₂(bte)(H₂O)₂]·2H₂O}_n, (II), were synthesized and structurally characterized by single-crystal X-ray analyses.

S2. Experimental

S2.1. Synthesis and crystallization

S2.1.1. Synthesis of complex (I)

A mixture of btb (0.0192 g, 0.1 mmol) and Cd(NO₃)₂·4H₂O (0.0246 g, 0.1 mmol) was dissolved in water (5 ml) and the solution was stirring for 2 h. To this solution was added a mixture of H₂pzdc (0.0168 g, 0.1 mmol) and NaOH (0.0080 g, 0.2 mmol) in water (5 ml). The solution was stirring continuously for 2 h and then filtered. The resulting colourless solution was allowed to stand at room temperature. After a week, colourless block-shaped crystals were collected and washed with di­ethyl ether three times (yield: 30%, based on Cd). Elemental analysis (%) calculated for C₂₀H₂₈Cd₂N₁₀O₁₄: C 28.02, H 3.29, N 16.34%; found: C 27.92, H 3.22, N 16.25%.

S2.1.2. Synthesis of complex (II)

A mixture of bte (0.0164 g, 0.1 mmol) and Cd(NO₃)₂·4H₂O (0.0246 g, 0.1 mmol) was dissolved in water (5 ml) and the solution was stirred for 2 h. To this solution was added a mixture of H₂pzdc (0.0168 g, 0.1 mmol) and NaOH (0.0080 g, 0.2 mmol) in water (5 ml). The resulting solution was stirred continuously for 2 h and then filtered. The colourless solution was allowed to stand at the room temperature. After a week, colourless block-shaped crystals were collected and washed with di­ethyl ether three times (yield: 35%, based on Cd). Elemental analysis (%) calculated for C₁₈H₂₀Cd₂N₁₀O₁₂: C 27.25, H 2.54, N 17.66%; found C 27.15, H 2.62, N 17.58%.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were treated as riding. C-bound H atoms were fixed geometrically and allowed to ride in their parent atom, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C) for aromatic H atoms, or C—H = 0.97 Å and U_iso(H) = 1.2U_eq(C) for methyl­ene H atoms. Water H atoms were located in a difference Fourier map. Their positions were geometrically optimized and they were constrained to ride on their parent atom, with O—H = 0.85–0.90 Å and U_iso(H) = 1.2U_eq(O).

S3. Results and discussion

Complex (I) crystallizes in the monoclinic space group P2₁/c and the asymmetric unit consists of one crystallographically independent Cd²⁺ cation, one pzdc^2- anion, half a btb ligand, two coordinated water molecules and one lattice water molecule. As shown in Fig. 1, each Cd²⁺ cation is coordinated by a couple of N and O atoms from one pzdc^2- anion, one triazole N atom from a btb ligand, one carboxyl­ate O atom from another symmetric pzdc^2- anion and two O atoms from coordinated aqua molecules, which generate a distorted CdN₂O₄ o­cta­hedral geometry. Two pairs of N and O atoms (N1, O1, N5 and O6) form the equatorial plane with a mean deviation of 0.142 Å, while atoms O5 and O4A (see Fig. 1 for symmetry code and Table 2 for bond lengths) are located in the axial direction, with Cd1—O bond lengths of 2.347 (2) and 2.247 (2) Å, respectively. In complex (I), each pzdc^2- ligand acts as a µ₂-bridge linking Cd²⁺ ions into an infinite one-dimensional chain with a Cd···Cd separation of 6.29 Å and weak π–π stacking inter­actions (centroid-to-centroid separation = 3.7888 Å and dihedral angle = 3.9°) are observed between adjacent pyrazine rings (Fig. 2). On the other hand, each btb ligand serves as a bidentate connector, in which two terminal triazole rings adopt a parallel trans conformation with a dihedral angle of 0.0017(?)°. With the connection of pzdc and btb ligands, complex (I) exhibits an inter­esting two-dimensional wave-like network (Fig. 2). Furthermore, extensive hydrogen-bonding inter­actions involving the coordinated water molecules, the lattice water molecules, the carboxyl­ate O atoms and the triazole N atoms result in the formation of a three-dimensional supra­molecular architecture (Fig. 3 and Table 3).

The three-dimensional cadmium coordination polymer (II) crystallizes in the triclinic space group P1 and the asymmetric unit consists of two crystallographically independent Cd²⁺ cations (Cd1 and Cd2 with the same occupanies of 0.50), one pzdc^2- anion, half a bis­(1,2,4-triazol-1-yl)ethane (bte) ligand, one coordinated water molecule and one lattice water molecule. As shown in Fig. 4, each Cd²⁺ cation is located in a distorted o­cta­hedral N₂O₄ coordination envirnonment. Atom Cd1 is coordinated by two N atoms and four O atoms, half of which are asymmetric and from one bte ligand, one pzdc^2- anion and one coordinated aqua molecule, respectively. Atoms, O3, O3A, O5 and O5A (see Fig. 4 for symmetry code) are coplanar and construct the equatorial plane of the o­cta­hedral geometry. Atoms N3 and N3A are located in the axial direction, with the same Cd—N bond length of 2.2922 (17) Å. For atom Cd2, the six coordination atoms are from four pzdc^2- anions, in which half ligands provide a pair of O and N atoms and the other half provide only one carboxyl­ate O atom. As in the case of Cd1, four O atoms around Cd2 (O1, O1D, O4C and O4E; see Table 4 for symmetry codes and bond lengths) are also coplanar and form the equatorial plane of the o­cta­hedral geometry, and two N atoms (N1 and N1D) are located in the axial direction, with the same Cd—N bond length of 2.3058 (18) Å. In complex (II), each pzdc^2- anion exhibits a tetra­dentate µ₃-coordination mode and assembles Cd²⁺ cations into a two-dimensional grid-like motif (Fig. 5). While each bte molecule acts as a bidentate bridging ligand with the trans triazole conformation to extend the two-dimensional grid into a three-dimensional framework, as shown in Fig. 6. Weak π–π stacking inter­actions between pyrazine and triazole rings [centroid-to-centroid separations = 3.7388, 3.7388 and 3.8613 Å; dihedral angles = 3.4, 2.5 and 4.0°] and hydrogen-bonding inter­actions involving the coordinated water molecule, the lattice water molecule, the carboxyl­ate O atoms, the pyrazine N atoms and the triazole N atoms have been observed (Table 5).

Comparing the structures of the two title complexes, it seems that the length of the flexible bis­(1,2,4-triazol-1-yl)alkane ligand and the coordination modes of the pzdc^2- anionic ligand might act as the key role in determining the structures. As a long flexible ligand generates a larger steric hindrance, this would prevent the complex extending towards higher dimensions. On the other hand, the pzdc^2- anionic ligand, with a complicated coordination mode, could result in a secondary building unit with higher dimensions, which is beneficial for the formation of three-dimensional architectures. The results indicate that flexible bis­(1,2,4-triazol-1-yl)alkanes combined with multi­carboxyl­ate ligands can produce versatile structures and could be used widely in the construction of coordination polymers.

Computing details

For both compounds, data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of complex (I), showing the atom-labelling scheme and 30% probability displacement ellipsoids. [Symmetry codes: (A) x, -y+1/2, z+1/2; (B) -x+1, -y, -z -1.]
	Fig. 2. The two-dimensional wave-like net of complex (I). The π–π stacking interactions are shown as red dashed lines. Water molecules and H atoms have been omitted for clarity.
	Fig. 3. A view of the crystal packing of complex (I). Hydrogen bonds are shown as red dashed lines.
	Fig. 4. The coordination environment of the Cd^2+ cation in complex (II), showing the atom-labelling scheme and 30% probability displacement ellipsoids. [Symmetry codes: (A) -x+1, -y+1, -z; (B) -x, -y, -z; (C) x-1, y, z; (D) -x-1, -y+1, -z+1; (E) -x, -y+1, -z+1.]
	Fig. 5. The two-dimensional grid-like structure constructed by pzdc^2- ligands in complex (II). Water molecules and H atoms have been omitted for clarity.
	Fig. 6. A view of the crystal packing of complex (II). The π–π stacking interactions are shown as red dashed lines and the hydrogen bonds are shown as yellow dashed lines.

(I) Poly[[tetraaqua[µ₂-1,4-bis(1,2,4-triazol-1-yl)butane-κ²N⁴:N^4']bis(µ₂-pyrazine-2,3-dicarboxylato-κ³N¹,O²:O³)dicadmium(II)] dihydrate]

Crystal data

[Cd2(C6H2N2O4)2(C8H12N6)(H2O)4]·2H2O	F(000) = 852
Mr = 857.32	Dx = 1.989 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3410 reflections
a = 7.6647 (5) Å	θ = 3.7–28.7°
b = 26.6935 (14) Å	µ = 1.57 mm^−1
c = 7.5350 (5) Å	T = 293 K
β = 111.787 (7)°	Block, colourless
V = 1431.52 (15) Å^3	0.20 × 0.15 × 0.15 mm
Z = 2

Data collection

Agilent SuperNova Single Source at offset diffractometer with an Eos detector	3077 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	2702 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.034
ω scans	θmax = 27.0°, θmin = 2.9°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013)	h = −9→7
Tmin = 0.744, Tmax = 0.798	k = −34→32
6708 measured reflections	l = −9→9

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)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.077	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0325P)^2] where P = (Fo^2 + 2Fc^2)/3
3077 reflections	(Δ/σ)max < 0.001
208 parameters	Δρmax = 0.68 e Å^−3
6 restraints	Δρmin = −0.79 e Å^−3

Special details

Experimental. Absorption correction: CrysAlisPro, Agilent Technologies, Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET) (compiled Aug 2 2013,16:46:58) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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 (Ų)

	x	y	z	Uiso*/Ueq
C2	0.4857 (4)	0.22808 (13)	−0.1467 (4)	0.0114 (7)
H2	0.3748	0.2171	−0.2412	0.014*
Cd1	1.00803 (3)	0.155428 (8)	0.32213 (3)	0.00899 (9)
O1	1.0810 (3)	0.23671 (8)	0.4014 (3)	0.0114 (5)
O5	1.2297 (3)	0.15697 (8)	0.1752 (3)	0.0106 (5)
H5B	1.3308	0.1741	0.2303	0.013*
H5A	1.1685	0.1710	0.0693	0.013*
O3	0.6046 (3)	0.37041 (9)	0.1042 (3)	0.0137 (5)
O4	0.8107 (3)	0.37028 (9)	−0.0382 (3)	0.0139 (5)
N2	0.5191 (3)	0.27704 (11)	−0.1241 (3)	0.0104 (6)
C6	0.7029 (4)	0.34893 (12)	0.0297 (4)	0.0103 (7)
N5	0.8945 (3)	0.08690 (10)	0.1280 (3)	0.0104 (6)
N1	0.7717 (3)	0.20770 (10)	0.1033 (3)	0.0083 (5)
C4	0.8062 (4)	0.25699 (12)	0.1293 (4)	0.0083 (6)
O6	1.2444 (3)	0.12226 (10)	0.5681 (3)	0.0208 (6)
H6A	1.3583	0.1280	0.5838	0.025*
H6B	1.2477	0.1141	0.6795	0.025*
C8	0.8141 (4)	0.04524 (13)	0.1672 (4)	0.0147 (7)
H8	0.8024	0.0401	0.2844	0.018*
N4	0.7543 (4)	0.01292 (11)	0.0274 (3)	0.0135 (6)
C1	0.6105 (4)	0.19295 (13)	−0.0343 (4)	0.0108 (6)
H1	0.5828	0.1590	−0.0540	0.013*
C3	0.6818 (4)	0.29218 (12)	0.0123 (4)	0.0071 (6)
C7	0.8804 (4)	0.07938 (13)	−0.0520 (4)	0.0108 (7)
H7	0.9222	0.1014	−0.1233	0.013*
N3	0.7975 (3)	0.03573 (10)	−0.1133 (3)	0.0096 (5)
C9	0.7410 (4)	0.01458 (13)	−0.3053 (4)	0.0137 (7)
H9A	0.8054	−0.0170	−0.2993	0.016*
H9B	0.7779	0.0372	−0.3859	0.016*
C10	0.5297 (4)	0.00604 (13)	−0.3934 (4)	0.0123 (7)
H10A	0.4646	0.0358	−0.3774	0.015*
H10B	0.4956	−0.0215	−0.3287	0.015*
O2	1.0152 (3)	0.31699 (9)	0.3249 (3)	0.0138 (5)
O7	0.3471 (3)	0.09068 (9)	0.9408 (3)	0.0196 (5)
H11	0.3358	0.0580	0.9642	0.024*
H12	0.3202	0.1081	1.0231	0.024*
C5	0.9835 (4)	0.27155 (13)	0.2982 (4)	0.0088 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C2	0.0088 (14)	0.0142 (18)	0.0090 (14)	−0.0038 (13)	0.0007 (12)	−0.0004 (13)
Cd1	0.00909 (13)	0.00583 (14)	0.01046 (14)	0.00041 (9)	0.00177 (10)	−0.00066 (9)
O1	0.0122 (10)	0.0060 (12)	0.0112 (10)	0.0023 (9)	−0.0012 (9)	0.0018 (9)
O5	0.0114 (11)	0.0078 (12)	0.0101 (10)	−0.0017 (9)	0.0011 (9)	−0.0005 (9)
O3	0.0109 (10)	0.0114 (13)	0.0197 (12)	−0.0002 (10)	0.0069 (9)	−0.0053 (10)
O4	0.0167 (11)	0.0120 (13)	0.0156 (11)	−0.0016 (10)	0.0093 (10)	0.0018 (10)
N2	0.0098 (12)	0.0107 (15)	0.0100 (12)	−0.0006 (11)	0.0028 (10)	−0.0034 (11)
C6	0.0076 (14)	0.0113 (17)	0.0074 (14)	0.0004 (13)	−0.0028 (12)	0.0006 (13)
N5	0.0112 (13)	0.0067 (14)	0.0130 (13)	−0.0016 (11)	0.0043 (11)	−0.0012 (11)
N1	0.0096 (12)	0.0074 (14)	0.0086 (12)	−0.0004 (11)	0.0043 (10)	0.0001 (11)
C4	0.0088 (14)	0.0084 (16)	0.0086 (14)	0.0004 (13)	0.0043 (12)	−0.0021 (12)
O6	0.0106 (11)	0.0370 (17)	0.0149 (11)	0.0041 (12)	0.0049 (9)	0.0122 (12)
C8	0.0159 (16)	0.0133 (18)	0.0125 (15)	−0.0032 (14)	0.0025 (13)	−0.0003 (14)
N4	0.0158 (13)	0.0097 (14)	0.0142 (13)	−0.0027 (12)	0.0048 (11)	0.0013 (11)
C1	0.0094 (14)	0.0094 (17)	0.0137 (15)	−0.0023 (13)	0.0045 (13)	−0.0049 (13)
C3	0.0083 (14)	0.0071 (16)	0.0071 (13)	−0.0009 (13)	0.0044 (12)	−0.0026 (12)
C7	0.0086 (14)	0.0092 (17)	0.0118 (15)	−0.0001 (13)	0.0006 (12)	0.0030 (13)
N3	0.0080 (12)	0.0077 (14)	0.0107 (12)	−0.0006 (11)	0.0008 (10)	−0.0028 (11)
C9	0.0157 (16)	0.0134 (18)	0.0108 (15)	−0.0005 (14)	0.0035 (13)	−0.0039 (13)
C10	0.0130 (15)	0.0093 (17)	0.0118 (15)	−0.0019 (14)	0.0014 (13)	−0.0041 (13)
O2	0.0144 (12)	0.0071 (12)	0.0146 (12)	−0.0023 (10)	−0.0009 (10)	−0.0017 (9)
O7	0.0343 (14)	0.0106 (13)	0.0182 (12)	0.0003 (11)	0.0147 (11)	0.0024 (10)
C5	0.0085 (14)	0.0096 (17)	0.0093 (14)	0.0000 (13)	0.0046 (12)	−0.0022 (12)

Geometric parameters (Å, º)

C2—N2	1.331 (4)	C4—C3	1.394 (4)
C2—C1	1.382 (4)	C4—C5	1.528 (4)
C2—H2	0.9300	O6—H6A	0.8503
Cd1—O6	2.238 (2)	O6—H6B	0.8585
Cd1—O4^i	2.247 (2)	C8—N4	1.306 (4)
Cd1—O1	2.265 (2)	C8—H8	0.9300
Cd1—N5	2.302 (3)	N4—N3	1.366 (3)
Cd1—O5	2.347 (2)	C1—H1	0.9300
Cd1—N1	2.394 (2)	C7—N3	1.325 (4)
O1—C5	1.263 (4)	C7—H7	0.9300
O5—H5B	0.8622	N3—C9	1.461 (3)
O5—H5A	0.8475	C9—C10	1.522 (4)
O3—C6	1.235 (4)	C9—H9A	0.9700
O4—C6	1.259 (4)	C9—H9B	0.9700
O4—Cd1^ii	2.247 (2)	C10—C10^iii	1.533 (5)
N2—C3	1.350 (4)	C10—H10A	0.9700
C6—C3	1.524 (4)	C10—H10B	0.9700
N5—C7	1.335 (3)	O2—C5	1.239 (4)
N5—C8	1.356 (4)	O7—H11	0.9004
N1—C4	1.342 (4)	O7—H12	0.8597
N1—C1	1.344 (4)
N2—C2—C1	122.1 (3)	Cd1—O6—H6A	121.2
N2—C2—H2	119.0	Cd1—O6—H6B	129.2
C1—C2—H2	119.0	H6A—O6—H6B	104.7
O6—Cd1—O4^i	88.27 (8)	N4—C8—N5	114.7 (3)
O6—Cd1—O1	96.65 (8)	N4—C8—H8	122.7
O4^i—Cd1—O1	108.21 (8)	N5—C8—H8	122.7
O6—Cd1—N5	102.17 (9)	C8—N4—N3	102.6 (3)
O4^i—Cd1—N5	83.88 (8)	N1—C1—C2	120.2 (3)
O1—Cd1—N5	157.98 (8)	N1—C1—H1	119.9
O6—Cd1—O5	83.84 (7)	C2—C1—H1	119.9
O4^i—Cd1—O5	163.18 (8)	N2—C3—C4	120.1 (3)
O1—Cd1—O5	87.50 (7)	N2—C3—C6	113.7 (3)
N5—Cd1—O5	83.29 (8)	C4—C3—C6	126.1 (3)
O6—Cd1—N1	166.92 (9)	N3—C7—N5	109.5 (3)
O4^i—Cd1—N1	91.82 (8)	N3—C7—H7	125.2
O1—Cd1—N1	70.91 (8)	N5—C7—H7	125.2
N5—Cd1—N1	90.83 (9)	C7—N3—N4	110.1 (2)
O5—Cd1—N1	99.21 (8)	C7—N3—C9	127.8 (3)
C5—O1—Cd1	120.73 (19)	N4—N3—C9	121.9 (3)
Cd1—O5—H5B	117.4	N3—C9—C10	111.4 (2)
Cd1—O5—H5A	101.9	N3—C9—H9A	109.3
H5B—O5—H5A	107.7	C10—C9—H9A	109.3
C6—O4—Cd1^ii	135.2 (2)	N3—C9—H9B	109.3
C2—N2—C3	118.1 (3)	C10—C9—H9B	109.3
O3—C6—O4	125.3 (3)	H9A—C9—H9B	108.0
O3—C6—C3	116.0 (3)	C9—C10—C10^iii	110.0 (3)
O4—C6—C3	118.7 (3)	C9—C10—H10A	109.7
C7—N5—C8	103.1 (3)	C10^iii—C10—H10A	109.7
C7—N5—Cd1	129.4 (2)	C9—C10—H10B	109.7
C8—N5—Cd1	127.5 (2)	C10^iii—C10—H10B	109.7
C4—N1—C1	118.3 (3)	H10A—C10—H10B	108.2
C4—N1—Cd1	114.41 (19)	H11—O7—H12	108.4
C1—N1—Cd1	127.2 (2)	O2—C5—O1	125.8 (3)
N1—C4—C3	121.1 (3)	O2—C5—C4	116.4 (3)
N1—C4—C5	115.9 (3)	O1—C5—C4	117.8 (3)
C3—C4—C5	122.9 (3)
O6—Cd1—O1—C5	179.2 (2)	C7—N5—C8—N4	0.7 (4)
O4^i—Cd1—O1—C5	−90.4 (2)	Cd1—N5—C8—N4	177.1 (2)
N5—Cd1—O1—C5	30.6 (4)	N5—C8—N4—N3	−0.8 (4)
O5—Cd1—O1—C5	95.7 (2)	C4—N1—C1—C2	0.7 (4)
N1—Cd1—O1—C5	−4.9 (2)	Cd1—N1—C1—C2	178.4 (2)
C1—C2—N2—C3	0.7 (5)	N2—C2—C1—N1	0.1 (5)
Cd1^ii—O4—C6—O3	179.18 (19)	C2—N2—C3—C4	−2.2 (4)
Cd1^ii—O4—C6—C3	−3.9 (4)	C2—N2—C3—C6	−178.3 (3)
O6—Cd1—N5—C7	−120.5 (3)	N1—C4—C3—N2	3.1 (4)
O4^i—Cd1—N5—C7	152.6 (3)	C5—C4—C3—N2	−174.1 (3)
O1—Cd1—N5—C7	27.6 (4)	N1—C4—C3—C6	178.6 (3)
O5—Cd1—N5—C7	−38.3 (3)	C5—C4—C3—C6	1.4 (5)
N1—Cd1—N5—C7	60.8 (3)	O3—C6—C3—N2	73.3 (3)
O6—Cd1—N5—C8	64.1 (3)	O4—C6—C3—N2	−103.9 (3)
O4^i—Cd1—N5—C8	−22.8 (2)	O3—C6—C3—C4	−102.5 (3)
O1—Cd1—N5—C8	−147.8 (2)	O4—C6—C3—C4	80.3 (4)
O5—Cd1—N5—C8	146.2 (3)	C8—N5—C7—N3	−0.3 (3)
N1—Cd1—N5—C8	−114.6 (3)	Cd1—N5—C7—N3	−176.62 (18)
O6—Cd1—N1—C4	22.4 (5)	N5—C7—N3—N4	−0.1 (4)
O4^i—Cd1—N1—C4	112.5 (2)	N5—C7—N3—C9	174.8 (3)
O1—Cd1—N1—C4	3.9 (2)	C8—N4—N3—C7	0.5 (3)
N5—Cd1—N1—C4	−163.6 (2)	C8—N4—N3—C9	−174.8 (3)
O5—Cd1—N1—C4	−80.2 (2)	C7—N3—C9—C10	−118.8 (3)
O6—Cd1—N1—C1	−155.4 (3)	N4—N3—C9—C10	55.6 (4)
O4^i—Cd1—N1—C1	−65.3 (2)	N3—C9—C10—C10^iii	168.7 (3)
O1—Cd1—N1—C1	−173.9 (2)	Cd1—O1—C5—O2	−177.2 (2)
N5—Cd1—N1—C1	18.6 (2)	Cd1—O1—C5—C4	5.2 (3)
O5—Cd1—N1—C1	102.0 (2)	N1—C4—C5—O2	−179.1 (3)
C1—N1—C4—C3	−2.3 (4)	C3—C4—C5—O2	−1.7 (4)
Cd1—N1—C4—C3	179.7 (2)	N1—C4—C5—O1	−1.2 (4)
C1—N1—C4—C5	175.1 (2)	C3—C4—C5—O1	176.1 (3)
Cd1—N1—C4—C5	−2.9 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O7—H12···O5^iv	0.86	2.02	2.870 (3)	170
O7—H11···N4^v	0.90	2.02	2.907 (4)	166
O6—H6B···O7^vi	0.86	1.93	2.752 (3)	159
O6—H6A···O3^vii	0.85	1.84	2.680 (3)	171
O5—H5A···O2^ii	0.85	1.81	2.632 (3)	164
O5—H5B···N2^vii	0.86	1.95	2.797 (3)	166

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

(II) Poly[[diaqua[µ₂-1,2-bis(1,2,4-triazol-1-yl)ethane-κ²N⁴:N^4']bis(µ₃-pyrazine-2,3-dicarboxylato-κ⁴N¹,O²:O³:O^3')dicadmium(II)] dihydrate]

Crystal data

[Cd2(C6H2N2O4)2(C6H8N6)(H2O)2]·2H2O	Z = 1
Mr = 793.24	F(000) = 390
Triclinic, P1	Dx = 2.139 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.0219 (14) Å	Cell parameters from 2710 reflections
b = 8.4215 (17) Å	θ = 3.0–37.0°
c = 10.913 (2) Å	µ = 1.81 mm^−1
α = 81.75 (3)°	T = 293 K
β = 84.05 (3)°	Block, colourless
γ = 75.12 (3)°	0.20 × 0.20 × 0.20 mm
V = 615.7 (2) Å^3

Data collection

Agilent SuperNova Single Source at offset diffractometer with an Eos detector	4808 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	3444 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.031
ω scans	θmax = 33.7°, θmin = 1.9°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013)	h = −10→10
Tmin = 0.713, Tmax = 0.713	k = −13→12
10451 measured reflections	l = −17→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)] = 0.029	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.070	H atoms treated by a mixture of independent and constrained refinement
S = 0.94	w = 1/[σ^2(Fo^2) + (0.0356P)^2] where P = (Fo^2 + 2Fc^2)/3
4808 reflections	(Δ/σ)max < 0.001
205 parameters	Δρmax = 0.53 e Å^−3
6 restraints	Δρmin = −1.08 e Å^−3

Special details

Experimental. Absorption correction: CrysAlisPro, Agilent Technologies, Version 1.171.36.32 (release 02-08-2013 CrysAlis171 .NET) (compiled Aug 2 2013,16:46:58) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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 (Ų)

	x	y	z	Uiso*/Ueq
O4	0.3777 (2)	0.5253 (2)	0.30499 (14)	0.0387 (4)
O1	−0.2373 (2)	0.32956 (19)	0.40511 (15)	0.0301 (3)
Cd1	0.5000	0.5000	0.0000	0.02208 (6)
Cd2	−0.5000	0.5000	0.5000	0.02788 (6)
C4	−0.1148 (3)	0.5737 (2)	0.36395 (16)	0.0175 (3)
N1	−0.2791 (2)	0.6568 (2)	0.42325 (15)	0.0217 (3)
N3	0.1936 (2)	0.1168 (2)	−0.00963 (15)	0.0203 (3)
O2	0.0525 (2)	0.31896 (19)	0.29731 (16)	0.0363 (4)
O3	0.2200 (2)	0.58772 (18)	0.13164 (13)	0.0249 (3)
N5	0.3442 (3)	0.3145 (2)	−0.05375 (16)	0.0244 (3)
C3	0.0341 (3)	0.6535 (2)	0.31771 (16)	0.0196 (3)
C5	−0.0986 (3)	0.3919 (2)	0.35391 (18)	0.0209 (4)
C6	0.2255 (3)	0.5784 (2)	0.24646 (18)	0.0210 (4)
N2	0.0167 (3)	0.8124 (2)	0.33432 (16)	0.0282 (4)
N4	0.3263 (3)	0.0704 (2)	−0.10608 (16)	0.0241 (3)
C8	0.4129 (3)	0.1947 (2)	−0.12922 (18)	0.0228 (4)
H8	0.5124	0.1994	−0.1919	0.027*
C2	−0.1467 (4)	0.8919 (3)	0.3932 (2)	0.0312 (5)
H2	−0.1612	1.0017	0.4051	0.037*
C7	0.2053 (3)	0.2611 (3)	0.0203 (2)	0.0254 (4)
H7	0.1283	0.3162	0.0832	0.030*
C1	−0.2967 (3)	0.8143 (3)	0.4375 (2)	0.0297 (5)
H1	−0.4109	0.8731	0.4776	0.036*
C9	0.0672 (3)	0.0094 (3)	0.04691 (19)	0.0250 (4)
H9A	−0.0116	0.0564	0.1174	0.030*
H9B	0.1482	−0.0984	0.0766	0.030*
O5	0.3630 (3)	0.7208 (2)	−0.15135 (15)	0.0362 (4)
H5A	0.387 (4)	0.690 (3)	−0.2236 (13)	0.043*
H5B	0.377 (4)	0.8195 (18)	−0.149 (2)	0.043*
O6	0.3069 (3)	0.0077 (3)	0.3244 (2)	0.0509 (5)
H6A	0.246 (4)	0.1098 (13)	0.308 (3)	0.061*
H6B	0.233 (4)	−0.060 (3)	0.322 (3)	0.061*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O4	0.0189 (7)	0.0721 (12)	0.0252 (7)	−0.0086 (8)	−0.0001 (6)	−0.0118 (8)
O1	0.0265 (8)	0.0286 (8)	0.0373 (8)	−0.0121 (6)	0.0094 (6)	−0.0096 (7)
Cd1	0.01893 (10)	0.01785 (10)	0.03305 (11)	−0.01051 (7)	0.00138 (8)	−0.00625 (8)
Cd2	0.01794 (10)	0.04618 (14)	0.02240 (10)	−0.01238 (9)	0.00707 (7)	−0.01152 (9)
C4	0.0160 (8)	0.0205 (8)	0.0153 (7)	−0.0031 (6)	0.0000 (6)	−0.0030 (6)
N1	0.0181 (7)	0.0252 (8)	0.0199 (7)	−0.0014 (6)	0.0020 (6)	−0.0064 (6)
N3	0.0225 (8)	0.0219 (8)	0.0209 (7)	−0.0139 (6)	0.0021 (6)	−0.0045 (6)
O2	0.0322 (9)	0.0234 (7)	0.0483 (10)	−0.0043 (6)	0.0197 (7)	−0.0090 (7)
O3	0.0252 (7)	0.0311 (8)	0.0186 (6)	−0.0084 (6)	0.0026 (5)	−0.0039 (6)
N5	0.0268 (8)	0.0245 (8)	0.0272 (8)	−0.0161 (7)	0.0050 (7)	−0.0079 (7)
C3	0.0210 (8)	0.0204 (9)	0.0172 (8)	−0.0055 (7)	0.0010 (6)	−0.0028 (7)
C5	0.0195 (9)	0.0214 (9)	0.0215 (8)	−0.0047 (7)	0.0022 (7)	−0.0045 (7)
C6	0.0195 (8)	0.0251 (9)	0.0206 (8)	−0.0109 (7)	0.0043 (7)	−0.0037 (7)
N2	0.0366 (10)	0.0235 (8)	0.0256 (8)	−0.0105 (7)	0.0017 (7)	−0.0039 (7)
N4	0.0266 (8)	0.0249 (8)	0.0244 (8)	−0.0127 (7)	0.0041 (7)	−0.0075 (7)
C8	0.0234 (9)	0.0264 (9)	0.0224 (8)	−0.0133 (8)	0.0040 (7)	−0.0061 (7)
C2	0.0429 (13)	0.0207 (10)	0.0291 (10)	−0.0041 (9)	0.0000 (9)	−0.0082 (8)
C7	0.0260 (10)	0.0272 (10)	0.0287 (10)	−0.0159 (8)	0.0066 (8)	−0.0115 (8)
C1	0.0289 (11)	0.0275 (10)	0.0291 (10)	0.0036 (8)	0.0007 (8)	−0.0122 (9)
C9	0.0287 (10)	0.0282 (10)	0.0235 (9)	−0.0192 (8)	−0.0018 (7)	0.0015 (8)
O5	0.0526 (11)	0.0288 (8)	0.0283 (8)	−0.0084 (8)	−0.0066 (8)	−0.0070 (7)
O6	0.0394 (11)	0.0422 (11)	0.0708 (14)	0.0005 (9)	−0.0053 (10)	−0.0240 (11)

Geometric parameters (Å, º)

O4—C6	1.251 (3)	N3—C9	1.457 (2)
O4—Cd2^i	2.3380 (17)	O2—C5	1.234 (2)
O1—C5	1.266 (2)	O3—C6	1.248 (2)
Cd1—O3	2.3342 (16)	N5—C7	1.328 (2)
Cd1—N5	2.2922 (17)	N5—C8	1.355 (3)
Cd1—N5^ii	2.2922 (17)	C3—N2	1.349 (2)
Cd2—O1	2.2817 (17)	C3—C6	1.516 (3)
Cd2—N1	2.3058 (18)	N2—C2	1.324 (3)
Cd2—N1^iii	2.3058 (18)	N4—C8	1.322 (2)
Cd1—O5	2.3748 (19)	C8—H8	0.9300
Cd1—O5^ii	2.3748 (19)	C2—C1	1.389 (3)
Cd1—O3^ii	2.3342 (16)	C2—H2	0.9300
Cd2—O1^iii	2.2817 (17)	C7—H7	0.9300
Cd2—O4^iv	2.3380 (17)	C1—H1	0.9300
Cd2—O4^v	2.3380 (17)	C9—C9^vi	1.513 (4)
C4—N1	1.342 (2)	C9—H9A	0.9700
C4—C3	1.398 (2)	C9—H9B	0.9700
C4—C5	1.524 (3)	O5—H5A	0.854 (9)
N1—C1	1.330 (3)	O5—H5B	0.865 (9)
N3—C7	1.328 (2)	O6—H6A	0.860 (9)
N3—N4	1.362 (2)	O6—H6B	0.867 (9)
C6—O4—Cd2^i	143.53 (14)	C7—N3—C9	129.31 (17)
C5—O1—Cd2	117.56 (13)	N4—N3—C9	119.97 (16)
N5^ii—Cd1—N5	180.00 (8)	C6—O3—Cd1	122.83 (13)
N5^ii—Cd1—O3	93.30 (6)	C7—N5—C8	103.67 (16)
N5—Cd1—O3	86.70 (6)	C7—N5—Cd1	122.53 (14)
N5^ii—Cd1—O3^ii	86.70 (6)	C8—N5—Cd1	129.03 (13)
N5—Cd1—O3^ii	93.30 (6)	N2—C3—C4	120.78 (18)
O3—Cd1—O3^ii	180.0	N2—C3—C6	113.06 (16)
N5^ii—Cd1—O5	84.10 (7)	C4—C3—C6	126.16 (17)
N5—Cd1—O5	95.90 (7)	O2—C5—O1	126.26 (19)
O3—Cd1—O5	88.21 (6)	O2—C5—C4	115.84 (17)
O3^ii—Cd1—O5	91.79 (6)	O1—C5—C4	117.90 (17)
N5^ii—Cd1—O5^ii	95.90 (7)	O3—C6—O4	125.41 (19)
N5—Cd1—O5^ii	84.10 (7)	O3—C6—C3	116.34 (18)
O3—Cd1—O5^ii	91.79 (6)	O4—C6—C3	117.97 (17)
O3^ii—Cd1—O5^ii	88.21 (6)	C2—N2—C3	118.36 (18)
O5—Cd1—O5^ii	180.00 (7)	C8—N4—N3	102.12 (16)
O1^iii—Cd2—O1	180.0	N4—C8—N5	114.22 (17)
O1^iii—Cd2—N1	106.97 (6)	N4—C8—H8	122.9
O1—Cd2—N1	73.03 (6)	N5—C8—H8	122.9
O1^iii—Cd2—N1^iii	73.03 (6)	N2—C2—C1	121.2 (2)
O1—Cd2—N1^iii	106.97 (6)	N2—C2—H2	119.4
N1—Cd2—N1^iii	180.0	C1—C2—H2	119.4
O1^iii—Cd2—O4^iv	98.88 (7)	N3—C7—N5	109.29 (18)
O1—Cd2—O4^iv	81.12 (7)	N3—C7—H7	125.4
N1—Cd2—O4^iv	91.82 (6)	N5—C7—H7	125.4
N1^iii—Cd2—O4^iv	88.18 (6)	N1—C1—C2	120.8 (2)
O1^iii—Cd2—O4^v	81.12 (7)	N1—C1—H1	119.6
O1—Cd2—O4^v	98.88 (7)	C2—C1—H1	119.6
N1—Cd2—O4^v	88.18 (6)	N3—C9—C9^vi	110.11 (19)
N1^iii—Cd2—O4^v	91.82 (6)	N3—C9—H9A	109.6
O4^iv—Cd2—O4^v	180.000 (1)	C9^vi—C9—H9A	109.6
N1—C4—C3	119.76 (17)	N3—C9—H9B	109.6
N1—C4—C5	117.11 (16)	C9^vi—C9—H9B	109.6
C3—C4—C5	123.10 (16)	H9A—C9—H9B	108.2
C1—N1—C4	119.13 (18)	Cd1—O5—H5A	110.1 (18)
C1—N1—Cd2	126.43 (14)	Cd1—O5—H5B	120.5 (18)
C4—N1—Cd2	114.36 (12)	H5A—O5—H5B	113.5 (15)
C7—N3—N4	110.71 (15)	H6A—O6—H6B	112.9 (16)
C5—O1—Cd2—O1^iii	−157 (100)	C5—C4—C3—N2	−176.73 (18)
C5—O1—Cd2—N1	−1.30 (15)	N1—C4—C3—C6	−178.53 (18)
C5—O1—Cd2—N1^iii	178.70 (15)	C5—C4—C3—C6	3.3 (3)
C5—O1—Cd2—O4^iv	93.36 (16)	Cd2—O1—C5—O2	−178.99 (18)
C5—O1—Cd2—O4^v	−86.64 (16)	Cd2—O1—C5—C4	2.2 (2)
C3—C4—N1—C1	−0.3 (3)	N1—C4—C5—O2	178.93 (19)
C5—C4—N1—C1	177.97 (18)	C3—C4—C5—O2	−2.8 (3)
C3—C4—N1—Cd2	−177.36 (14)	N1—C4—C5—O1	−2.2 (3)
C5—C4—N1—Cd2	0.9 (2)	C3—C4—C5—O1	176.08 (19)
O1^iii—Cd2—N1—C1	3.30 (19)	Cd1—O3—C6—O4	1.4 (3)
O1—Cd2—N1—C1	−176.70 (19)	Cd1—O3—C6—C3	175.13 (11)
N1^iii—Cd2—N1—C1	−167 (100)	Cd2^i—O4—C6—O3	170.68 (17)
O4^iv—Cd2—N1—C1	103.16 (18)	Cd2^i—O4—C6—C3	−3.0 (4)
O4^v—Cd2—N1—C1	−76.84 (18)	N2—C3—C6—O3	−92.6 (2)
O1^iii—Cd2—N1—C4	−179.92 (13)	C4—C3—C6—O3	87.4 (2)
O1—Cd2—N1—C4	0.08 (13)	N2—C3—C6—O4	81.6 (2)
N1^iii—Cd2—N1—C4	10 (100)	C4—C3—C6—O4	−98.4 (2)
O4^iv—Cd2—N1—C4	−80.06 (14)	C4—C3—N2—C2	−1.4 (3)
O4^v—Cd2—N1—C4	99.94 (14)	C6—C3—N2—C2	178.59 (19)
N5^ii—Cd1—O3—C6	−61.20 (15)	C7—N3—N4—C8	−0.1 (2)
N5—Cd1—O3—C6	118.80 (15)	C9—N3—N4—C8	−178.81 (18)
O3^ii—Cd1—O3—C6	91 (100)	N3—N4—C8—N5	0.3 (2)
O5—Cd1—O3—C6	−145.18 (15)	C7—N5—C8—N4	−0.4 (3)
O5^ii—Cd1—O3—C6	34.82 (15)	Cd1—N5—C8—N4	155.05 (15)
N5^ii—Cd1—N5—C7	25 (100)	C3—N2—C2—C1	0.3 (3)
O3—Cd1—N5—C7	−24.45 (18)	N4—N3—C7—N5	−0.2 (3)
O3^ii—Cd1—N5—C7	155.55 (18)	C9—N3—C7—N5	178.42 (19)
O5—Cd1—N5—C7	−112.31 (18)	C8—N5—C7—N3	0.3 (2)
O5^ii—Cd1—N5—C7	67.69 (18)	Cd1—N5—C7—N3	−157.16 (14)
N5^ii—Cd1—N5—C8	−127 (100)	C4—N1—C1—C2	−0.8 (3)
O3—Cd1—N5—C8	−175.83 (18)	Cd2—N1—C1—C2	175.85 (16)
O3^ii—Cd1—N5—C8	4.17 (18)	N2—C2—C1—N1	0.8 (4)
O5—Cd1—N5—C8	96.32 (18)	C7—N3—C9—C9^vi	118.3 (3)
O5^ii—Cd1—N5—C8	−83.68 (18)	N4—N3—C9—C9^vi	−63.2 (3)
N1—C4—C3—N2	1.5 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H6A···O2	0.86 (1)	1.93 (1)	2.763 (3)	164 (3)
O5—H5A···O4^ii	0.85 (1)	2.33 (2)	2.974 (3)	133 (2)
O5—H5A···O1^vii	0.85 (1)	2.38 (2)	3.109 (2)	143 (3)
O5—H5B···N4^viii	0.87 (1)	2.16 (1)	2.997 (2)	162 (2)
O6—H6B···N2^ix	0.87 (1)	2.06 (1)	2.914 (3)	169 (3)

Symmetry codes: (ii) −x+1, −y+1, −z; (vii) −x, −y+1, −z; (viii) x, y+1, z; (ix) x, y−1, z.