A two-dimensional CdII coordination polymer: poly[di­aqua­[μ3-5,6-bis­(pyridin-2-yl)pyrazine-2,3-di­carboxyl­ato-κ5O2:O3:O3,N4,N5]cadmium]

Alfonso, M.; Stoeckli-Evans, H.

doi:10.1107/S2056989016012858

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 72| Part 9| September 2016| Pages 1297-1300

https://doi.org/10.1107/S2056989016012858

Open

access

A two-dimensional Cd^II coordination polymer: poly[diaqua[μ₃-5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylato-κ⁵O²:O³:O³,N⁴,N⁵]cadmium]

Monserrat Alfonso ^a and Helen Stoeckli-Evans ^b ^*

^aInstitute of Chemistry, University of Neuchâtel, Av Bellevaux 51, CH-2000 Neuchâtel, Switzerland, and ^bInstitute of Physics, University of Neuchâtel, rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
^*Correspondence e-mail: helen.stoeckli-evans@unine.ch

Edited by S. Parkin, University of Kentucky, USA (Received 31 July 2016; accepted 9 August 2016; online 16 August 2016)

The reaction of 5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylic acid with cadmium dichloride leads to the formation of the title two-dimensional coordination polymer, [Cd(C₁₆H₈N₄O₄)(H₂O)₂]_n. The metal atom is sevenfold coordinated by one pyrazine and one pyridine N atom, two water O atoms, and by two carboxylate O atoms, one of which bridges two Cd^II atoms to form a Cd₂O₂ unit situated about a centre of inversion. Hence, the ligand coordinates to the cadmium atom in an N,N′,O-tridentate and an O-monodentate manner. Within the polymer network, there are a number of O—H⋯O hydrogen bonds present, involving the water molecules and the carboxylate O atoms. There are also C—H⋯N and C—H⋯O hydrogen bonds present. In the crystal, the polymer networks lie parallel to the bc plane. They are aligned back-to-back along the a axis with the non-coordinating pyridine rings directed into the space between the networks.

Keywords: crystal structure; cadmium(II); sevenfold coordination; pentagonal bipyramid; two-dimensional coordination polymer; network; hydrogen bonding.

CCDC reference: 1498382

1. Chemical context

The crystal structure of the ligand 5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylic acid (H₂L) and the chloride, perchlorate and hexafluorophosphate salts, have been reported on previously (Alfonso et al., 2001 ). Interestingly, the ligand crystallizes as a zwitterion in all four compounds. The reaction of H₂L with CuBr₂ (ratio 1:2) leads to the formation of a one-dimensional coordination polymer. On exposure to air, the compound loses the solvent of crystallization and four water molecules, transforming into a two-dimensional coordination polymer (Neels et al., 2003 ). In both cases, there are two crystallographically independent fivefold-coordinated copper atoms present and they all have almost perfect square-pyramidal geometry. Recently, we have reported on the crystal structures of the dimethyl and diethyl ester of the H₂L ligand (Alfonso & Stoeckli-Evans, 2016a ). The reaction of the dimethyl ester of H₂L with CdCl₂ and HgCl₂ leads to the formation of isotypic one-dimensional coordination polymers (Alfonso & Stoeckli-Evans, 2016b ). There the ligand coordinates to the metal atom via the pyridine N atoms, and they have MN₂Cl₂ fourfold bisphenoidal coordination geometry.

2. Structural commentary

The reaction of 5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylic acid with cadmium dichloride leads to the formation of the title two-dimensional coordination polymer (Fig. 1). Here the metal atom is sevenfold coordinated by one pyrazine N atom (N1), one pyridine N atom (N3) and two water O atoms (O1W and O2W), and by two carboxylate O atoms (O1 and O3). Atom O1 bridges two cadmium atoms to form a Cd₂O₂ unit situated about a centre of inversion; the Cd1⋯Cd1ⁱⁱ distance is 3.8753 (8) Å, while the Cd—O1 and Cd—O1ⁱⁱ bonds are, respectively, 2.371 (4) and 2.427 (4) Å, and the Cd1—O1⋯Cd1ⁱⁱ and O1—Cd⋯O1ⁱⁱ bond angles are 107.74 (13) and 72.26 (13)°, respectively. As can be seen in Fig. 1, the ligand coordinates to the cadmium atom in a tridentate (N,N,O) and a monodentate manner (O). It can be seen from the carboxylate C—O bond lengths [C15—O1 and C15—O2 are 1.255 (6) and 1.253 (6) Å, respectively, while C16—O3 and C16—O4 are 1.258 (6) and 1.227 (6) Å, respectively] that the negative charge is distributed over the O–C–O group for the first, but located on atom O3 for the second.

Figure 1
A view of the molecular structure of the title coordination polymer, showing the atom labelling [symmetry codes: (i) x, −y + $[{1\over 2}]$ , z − $[{1\over 2}]$ ; (ii) −x + 1, −y + 1, −z + 1; (iii) x, −y + $[{1\over 2}]$ , z + $[{1\over 2}]$ ]. Displacement ellipsoids are drawn at the 50% probability level.

Selected bond lengths and angles involving atom Cd1 are given in Table 1. The Cd—N_pyrazine (Cd1—N1) and the Cd—N_pyridine (Cd1—N3) bond lengths are the same within 3 s.u.s. [2.418 (4) cf. 2.430 (4) Å]. The Cd—O_water bond lengths [2.301 (4) and 2.317 (3) Å] are shorter than the Cd—O_carboxylate bond lengths [2.371 (4) and 2.377 (4) Å], while the bridging Cd1⋯O1ⁱⁱ distance is the longest at 2.427 (4) Å. The geometry of the sevenfold-coordinated cadmium atom can best be described as a distorted pentagonal bipyramid, with atoms O1,N1,N3,O2W,O1ⁱⁱ in the basal plane and atoms O1W,O3ⁱ in the apical positions with an O1W—Cd1—O3ⁱ bond angle of 157.41 (15)° (Table 1).

Table 1
Selected geometric parameters (Å, °)

Cd1—O1	2.371 (4)	Cd1—N3	2.430 (4)
Cd1—O3ⁱ	2.377 (4)	Cd1—O1W	2.301 (4)
Cd1—N1	2.418 (4)	Cd1—O2W	2.317 (3)
Cd1—O1ⁱⁱ	2.427 (4)

Cd1—O1—Cd1ⁱⁱ	107.74 (13)	O1W—Cd1—N1	91.62 (16)
O1W—Cd1—O3ⁱ	157.41 (15)	O1W—Cd1—N3	87.87 (15)
O1—Cd1—O1ⁱⁱ	72.26 (13)	O1W—Cd1—O1ⁱⁱ	76.59 (15)
O1—Cd1—N1	67.98 (13)	O2W—Cd1—O3ⁱ	87.05 (13)
N1—Cd1—N3	65.40 (14)	O1—Cd1—O3ⁱ	80.38 (12)
O2W—Cd1—N3	78.01 (13)	O3ⁱ—Cd1—N1	91.67 (13)
O2W—Cd1—O1ⁱⁱ	80.65 (13)	O3ⁱ—Cd1—O1ⁱⁱ	86.60 (12)
O1W—Cd1—O2W	104.67 (16)	O3ⁱ—Cd1—N3	113.74 (13)
O1W—Cd1—O1	80.18 (15)
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) -x+1, -y+1, -z+1.

The coordinated pyridine ring (N3/C5-C9) and the carboxylate group (O1/O2/C15) are inclined to the pyrazine ring (r.m.s. deviation = 0.03 Å) by 16.9 (2) and 1.9 (6)°, respectively. The non-coordinating pyridine ring (N4/C10–C14) and the second coordinating carboxylate group (O3/O4/C16) are inclined to the pyrazine ring by 60.2 (3) and 89.1 (11)°, respectively. The two pyridine rings are inclined to one another by 75.4 (3) °.

3. Supramolecular features

In the crystal, the two-dimensional polymer networks lie parallel to the bc plane, as illustrated in Figs. 2 and 3. The networks are aligned back-to-back along the a axis, with the non-coordinating pyridine rings directed into the space between the networks (Fig. 4). Within the networks there are a number of O—H⋯O hydrogen bonds present, involving the water molecules and the carboxylate O atoms (Table 2 and Fig. 5). There are also C—H⋯O and C—H⋯N hydrogen bonds present within the network (Table 2).

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1WA⋯O3ⁱⁱⁱ	0.82 (2)	2.22 (3)	2.974 (6)	152 (5)
O1W—H1WB⋯O2^iv	0.84 (2)	2.05 (4)	2.805 (6)	150 (7)
O2W—H2WA⋯O4ⁱ	0.85 (2)	1.88 (3)	2.630 (6)	146 (5)
O2W—H2WB⋯O2ⁱⁱ	0.85 (2)	1.88 (2)	2.692 (5)	159 (5)
C9—H9⋯O3^v	0.94	2.52	3.245 (6)	134
C14—H14⋯N4^vi	0.94	2.62	3.372 (8)	137
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) -x+1, -y+1, -z+1; (iii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iv) x, y+1, z; (v) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ ; (vi) -x, -y+1, -z+1.

Figure 2
A view along the a axis of the title two-dimensional coordination polymer. The C-bound H atoms have been omitted for clarity.

Figure 3
A view along the c axis of the title two-dimensional coordination polymer. The C-bound H atoms have been omitted for clarity.

Figure 4
A view in projection down the c axis of the crystal packing of the title two-dimensional coordination polymer. The C-bound H atoms have been omitted for clarity.

Figure 5
A view normal to plane (1 $[\overline{1}]$ 0) of the O—H⋯O hydrogen bonds (dashed lines; see Table 2

) within the polymer network, involving the carboxylate O atoms (red balls) and the coordinating water molecules. The C atoms and C-bound H atoms of the ligand have been omitted for clarity.

4. Database survey

A search of the Cambridge Structural Database (CSD, Version 5.37, last update May 2016; Groom et al., 2016 ) for the ligand H₂L gave eight hits. All of these structures have been mentioned in the Chemical context above. A search for cadmium complexes with the Cd atom coordinated by two N atoms, two water molecules and three O atoms, two of which are carboxylate O atoms, gave seven hits. One of these compounds, catena-[(μ₂-1,1′-(butane-1,4-diyl)bis(5,6-dimethyl-1H-benzimidazole)]bis(μ₂-pyridine-2,6-dicarboxylato)tetraaquadicadmium dihydrate) [CSD refcode: FAVHIV; Jiao et al., 2012 ] has a Cd₂O₂ unit formed about an inversion centre as in the title compound. In FAVHIV, the Cd⋯Cd distance and the angles Cd—O⋯Cd and O—Cd⋯O are, respectively, 4.0408 (5) Å, and 111.05 (8) and 68.95 (7)°, compared to 3.8753 (8) Å, and 107.74 (13) and 72.26 (13) °, respectively, in the title compound. However, such an arrangement is extremely common for cadmium(II) complexes (over 600 hits in the CSD) and the bond lengths and angles vary enormously; for example the Cd⋯Cd distance varies from ca 3.0 to 4.3 Å, the Cd—O⋯Cd angle varies from ca 82 to 119° and the O—Cd⋯O angle from ca 60 to 90°.

5. Synthesis and crystallization

The synthesis of the ligand 5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylic acid (H₂L) has been reported previously (Alfonso et al., 2001).

Synthesis of the title coordination polymer: H₂L (32 mg, 0.10 mmol) was added to an aqueous solution (25 ml) of CdCl₂·2H₂O (22 mg, 0.10 mmol). The colourless solution immediately obtained was stirred for 1 h at room temperature. The reaction mixture was then filtered and the filtrate allowed to evaporate slowly at room temperature. After two weeks, small colourless plate-like crystals of the title compound were obtained, separated by filtration and dried in air (yield: 40 mg, 42.5%). Selected IR bands (KBr pellet, cm⁻¹): ν 1630(m), 1598(vs), 1533(m), 1469(m), 1442(m), 1414(m), 1362(s), 1301(m), 1273(m), 1176(m), 1165(m), 1119(m), 1043(w), 992(w), 829(m), 789(m), 759(m), 675(m), 562(m), 513(m). Analysis for C₁₆H₁₂N₄O₆Cd (468.71): calculated: C 41.00, H 2.58, N 11.95%; found: C 40.70, H 2.43, N 11.80%.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. The water H atoms were located in a difference Fourier map and refined with distance restraints: O—H = 0.84 (2) and H⋯H = 1.35 (2) Å, with U_iso(H) = 1.5U_eq(O). The C-bound H atoms were included in calculated positions and treated as riding atoms: C—H = 0.94 Å with U_iso(H) = 1.2U_eq(C). The best crystal available was extremely thin (0.01 mm) and as the shape of the crystal was irregular it was not possible to carry out a numerical absorption correction. The displacement ellipsoids for two carboxylate O atoms (O2 and O4) and a water O atom (OW1) are large but attempts to split these atoms were not successful.

Table 3
Experimental details

Crystal data
Chemical formula	[Cd(C₁₆H₈N₄O₄)(H₂O)₂]
M_r	468.70
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	223
a, b, c (Å)	16.6854 (12), 7.0799 (6), 13.4537 (10)
β (°)	96.236 (9)
V (Å³)	1579.9 (2)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.43
Crystal size (mm)	0.30 × 0.20 × 0.01

Data collection
Diffractometer	Stoe IPDS 1 image plate
Absorption correction	Multi-scan (MULABS; Spek, 2009 )
T_min, T_max	0.900, 1.00
No. of measured, independent and observed [I > 2σ(I)] reflections	11782, 3056, 1781
R_int	0.129
(sin θ/λ)_max (Å⁻¹)	0.615

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.038, 0.063, 0.75
No. of reflections	3056
No. of parameters	257
No. of restraints	6
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.53, −0.59
Computer programs: EXPOSE, CELL and INTEGRATE in IPDS-I (Stoe & Cie, 2004 ), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), Mercury (Macrae et al., 2008 ), PLATON (Spek, 2009) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1498382

Crystal structure: contains datablocks I, Global. DOI: https://doi.org/10.1107/S2056989016012858/pk2589sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989016012858/pk2589Isup2.hkl

checkCIF report

Computing details top

Data collection: EXPOSE in IPDS-I (Stoe & Cie, 2004); cell refinement: CELL in IPDS-I (Stoe & Cie, 2004); data reduction: INTEGRATE in IPDS-I (Stoe & Cie, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Poly[diaqua[µ₃-5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylato-κ⁵O²:O³:O³,N⁴,N⁵]cadmium] top

Crystal data top

[Cd(C₁₆H₈N₄O₄)(H₂O)₂]	F(000) = 928
M_r = 468.70	D_x = 1.970 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 16.6854 (12) Å	Cell parameters from 5000 reflections
b = 7.0799 (6) Å	θ = 1.7–26.1°
c = 13.4537 (10) Å	µ = 1.43 mm⁻¹
β = 96.236 (9)°	T = 223 K
V = 1579.9 (2) Å³	Plate, colourless
Z = 4	0.30 × 0.20 × 0.01 mm

Data collection top

Stoe IPDS 1 image plate diffractometer	3056 independent reflections
Radiation source: fine-focus sealed tube	1781 reflections with I > 2σ(I)
Plane graphite monochromator	R_int = 0.129
φ rotation scans	θ_max = 25.9°, θ_min = 2.5°
Absorption correction: multi-scan (MULABS; Spek, 2009)	h = −20→20
T_min = 0.900, T_max = 1.00	k = −8→8
11782 measured reflections	l = −16→16

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.038	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.063	w = 1/[σ²(F_o²) + (0.0062P)²] where P = (F_o² + 2F_c²)/3
S = 0.75	(Δ/σ)_max = 0.001
3056 reflections	Δρ_max = 0.53 e Å⁻³
257 parameters	Δρ_min = −0.59 e Å⁻³
6 restraints	Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00055 (16)

Special details top

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.

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

	x	y	z	U_iso*/U_eq
Cd1	0.39911 (3)	0.63678 (6)	0.47689 (3)	0.01231 (13)
O1	0.4663 (2)	0.3932 (6)	0.5741 (2)	0.0160 (9)
O2	0.4579 (2)	0.1638 (6)	0.6875 (3)	0.0266 (10)
O3	0.3636 (2)	0.1259 (6)	0.8712 (2)	0.0207 (9)
O4	0.3010 (3)	−0.0413 (6)	0.7454 (3)	0.0436 (14)
O1W	0.4770 (3)	0.8162 (6)	0.5928 (3)	0.0412 (13)
H1WA	0.520 (2)	0.780 (9)	0.623 (4)	0.062*
H1WB	0.457 (3)	0.898 (7)	0.628 (4)	0.062*
O2W	0.3837 (2)	0.8219 (5)	0.3341 (2)	0.0189 (10)
H2WA	0.355 (2)	0.766 (7)	0.287 (3)	0.028*
H2WB	0.4295 (16)	0.833 (8)	0.312 (3)	0.028*
N1	0.3193 (3)	0.5188 (6)	0.6031 (3)	0.0130 (10)
N2	0.2284 (3)	0.3495 (7)	0.7347 (3)	0.0156 (10)
N3	0.2853 (2)	0.8351 (6)	0.5067 (3)	0.0131 (10)
N4	0.0603 (3)	0.5341 (6)	0.6152 (3)	0.0222 (12)
C1	0.2472 (3)	0.5920 (7)	0.6161 (3)	0.0096 (12)
C2	0.2003 (3)	0.4982 (7)	0.6816 (4)	0.0128 (13)
C3	0.3478 (3)	0.3673 (9)	0.6546 (3)	0.0100 (10)
C4	0.3025 (3)	0.2842 (7)	0.7250 (4)	0.0102 (13)
C5	0.2290 (3)	0.7774 (7)	0.5650 (4)	0.0122 (13)
C6	0.1657 (3)	0.8955 (8)	0.5818 (3)	0.0186 (14)
H6	0.1260	0.8536	0.6211	0.022*
C7	0.1608 (4)	1.0747 (7)	0.5410 (4)	0.0196 (14)
H7	0.1174	1.1544	0.5516	0.024*
C8	0.2194 (3)	1.1351 (9)	0.4850 (3)	0.0166 (11)
H8	0.2175	1.2573	0.4576	0.020*
C9	0.2815 (3)	1.0138 (7)	0.4696 (4)	0.0156 (13)
H9	0.3224	1.0560	0.4322	0.019*
C10	0.1146 (4)	0.5462 (7)	0.6958 (4)	0.0179 (14)
C11	0.0946 (4)	0.5917 (8)	0.7907 (4)	0.0249 (15)
H11	0.1347	0.6018	0.8453	0.030*
C12	0.0141 (4)	0.6216 (10)	0.8025 (4)	0.0285 (14)
H12	−0.0016	0.6492	0.8660	0.034*
C13	−0.0426 (4)	0.6106 (9)	0.7204 (5)	0.0333 (16)
H13	−0.0974	0.6328	0.7263	0.040*
C14	−0.0169 (4)	0.5661 (8)	0.6298 (5)	0.0294 (17)
H14	−0.0560	0.5574	0.5741	0.035*
C15	0.4309 (3)	0.3025 (7)	0.6364 (4)	0.0140 (14)
C16	0.3259 (3)	0.1061 (8)	0.7857 (4)	0.0146 (13)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.0136 (2)	0.01131 (19)	0.01235 (19)	0.0013 (3)	0.00290 (13)	0.0012 (2)
O1	0.015 (2)	0.019 (2)	0.0148 (18)	−0.001 (2)	0.0050 (16)	0.0052 (18)
O2	0.023 (2)	0.026 (3)	0.034 (2)	0.013 (2)	0.0159 (18)	0.021 (2)
O3	0.032 (2)	0.019 (2)	0.0108 (18)	0.011 (2)	0.0008 (17)	−0.002 (2)
O4	0.064 (4)	0.015 (2)	0.042 (3)	−0.011 (2)	−0.039 (3)	0.003 (2)
O1W	0.029 (3)	0.032 (3)	0.057 (3)	0.010 (2)	−0.018 (2)	−0.031 (2)
O2W	0.017 (2)	0.023 (3)	0.017 (2)	−0.003 (2)	−0.0011 (17)	0.0062 (17)
N1	0.012 (3)	0.017 (3)	0.010 (2)	0.003 (2)	0.003 (2)	−0.0037 (19)
N2	0.018 (3)	0.015 (2)	0.014 (2)	0.005 (3)	−0.0004 (19)	0.002 (2)
N3	0.014 (3)	0.007 (3)	0.018 (2)	0.002 (2)	0.0006 (19)	0.0031 (19)
N4	0.012 (3)	0.027 (3)	0.028 (3)	0.004 (2)	0.004 (2)	0.002 (2)
C1	0.005 (3)	0.017 (3)	0.008 (2)	0.001 (2)	0.004 (2)	−0.002 (2)
C2	0.010 (3)	0.014 (3)	0.014 (3)	−0.007 (3)	−0.002 (2)	−0.002 (2)
C3	0.013 (3)	0.010 (2)	0.007 (2)	−0.004 (3)	0.001 (2)	0.001 (3)
C4	0.012 (3)	0.010 (3)	0.009 (3)	−0.005 (3)	0.002 (2)	−0.003 (2)
C5	0.008 (3)	0.017 (3)	0.013 (3)	0.000 (3)	0.004 (2)	−0.001 (2)
C6	0.019 (3)	0.021 (4)	0.016 (3)	0.004 (3)	0.007 (2)	0.003 (3)
C7	0.023 (4)	0.015 (3)	0.021 (3)	0.011 (3)	0.003 (3)	−0.004 (2)
C8	0.027 (3)	0.007 (2)	0.016 (3)	0.004 (3)	0.003 (2)	0.001 (3)
C9	0.020 (4)	0.017 (3)	0.011 (3)	−0.002 (3)	0.006 (3)	0.001 (2)
C10	0.020 (4)	0.014 (3)	0.020 (3)	0.002 (3)	0.003 (3)	0.006 (2)
C11	0.025 (4)	0.024 (4)	0.026 (3)	0.002 (3)	0.009 (3)	0.004 (3)
C12	0.032 (4)	0.021 (3)	0.037 (3)	0.003 (4)	0.021 (3)	0.004 (3)
C13	0.021 (4)	0.022 (4)	0.060 (4)	0.003 (4)	0.017 (3)	0.002 (4)
C14	0.013 (4)	0.028 (4)	0.045 (4)	0.003 (3)	−0.004 (3)	0.006 (3)
C15	0.015 (4)	0.015 (3)	0.012 (3)	−0.003 (3)	0.002 (3)	−0.006 (2)
C16	0.016 (3)	0.012 (3)	0.017 (3)	0.005 (3)	0.005 (2)	0.002 (3)

Geometric parameters (Å, º) top

Cd1—O1	2.371 (4)	N4—C14	1.344 (7)
Cd1—O3ⁱ	2.377 (4)	C1—C2	1.407 (7)
Cd1—N1	2.418 (4)	C1—C5	1.498 (7)
Cd1—O1ⁱⁱ	2.427 (4)	C2—C10	1.502 (8)
Cd1—N3	2.430 (4)	C3—C4	1.403 (7)
Cd1—O1W	2.301 (4)	C3—C15	1.506 (7)
Cd1—O2W	2.317 (3)	C4—C16	1.530 (7)
O1—C15	1.255 (6)	C5—C6	1.384 (7)
O1—Cd1ⁱⁱ	2.427 (3)	C6—C7	1.381 (7)
O2—C15	1.253 (6)	C6—H6	0.9400
O3—C16	1.258 (6)	C7—C8	1.366 (7)
O3—Cd1ⁱⁱⁱ	2.377 (4)	C7—H7	0.9400
O4—C16	1.227 (6)	C8—C9	1.378 (7)
O1W—H1WA	0.82 (2)	C8—H8	0.9400
O1W—H1WB	0.837 (19)	C9—H9	0.9400
O2W—H2WA	0.847 (19)	C10—C11	1.392 (7)
O2W—H2WB	0.852 (19)	C11—C12	1.386 (8)
N1—C3	1.335 (7)	C11—H11	0.9400
N1—C1	1.339 (6)	C12—C13	1.376 (8)
N2—C2	1.328 (7)	C12—H12	0.9400
N2—C4	1.341 (7)	C13—C14	1.373 (8)
N3—C5	1.351 (6)	C13—H13	0.9400
N3—C9	1.359 (6)	C14—H14	0.9400
N4—C10	1.338 (7)

Cd1—O1—Cd1ⁱⁱ	107.74 (13)	C1—C2—C10	125.1 (5)
O1W—Cd1—O3ⁱ	157.41 (15)	N1—C3—C4	120.0 (5)
O1—Cd1—O1ⁱⁱ	72.26 (13)	N1—C3—C15	116.3 (4)
O1—Cd1—N1	67.98 (13)	C4—C3—C15	123.6 (5)
N1—Cd1—N3	65.40 (14)	N2—C4—C3	119.4 (5)
O2W—Cd1—N3	78.01 (13)	N2—C4—C16	114.6 (4)
O2W—Cd1—O1ⁱⁱ	80.65 (13)	C3—C4—C16	125.6 (5)
O1W—Cd1—O2W	104.67 (16)	N3—C5—C6	120.2 (5)
O1W—Cd1—O1	80.18 (15)	N3—C5—C1	114.3 (5)
O1W—Cd1—N1	91.62 (16)	C6—C5—C1	125.1 (5)
O1W—Cd1—N3	87.87 (15)	C7—C6—C5	120.3 (5)
O1W—Cd1—O1ⁱⁱ	76.59 (15)	C7—C6—H6	119.9
O2W—Cd1—O3ⁱ	87.05 (13)	C5—C6—H6	119.9
O1—Cd1—O3ⁱ	80.38 (12)	C8—C7—C6	119.4 (5)
O3ⁱ—Cd1—N1	91.67 (13)	C8—C7—H7	120.3
O3ⁱ—Cd1—O1ⁱⁱ	86.60 (12)	C6—C7—H7	120.3
O3ⁱ—Cd1—N3	113.74 (13)	C7—C8—C9	118.9 (5)
O2W—Cd1—N1	139.31 (15)	C7—C8—H8	120.6
O2W—Cd1—O1	150.65 (13)	C9—C8—H8	120.6
N1—Cd1—O1ⁱⁱ	139.91 (14)	N3—C9—C8	122.1 (5)
O1—Cd1—N3	131.34 (12)	N3—C9—H9	119.0
O1ⁱⁱ—Cd1—N3	149.40 (14)	C8—C9—H9	119.0
C15—O1—Cd1	120.8 (3)	N4—C10—C11	123.3 (5)
C15—O1—Cd1ⁱⁱ	131.4 (4)	N4—C10—C2	116.9 (5)
C16—O3—Cd1ⁱⁱⁱ	121.8 (4)	C11—C10—C2	119.7 (5)
Cd1—O1W—H1WA	124 (4)	C12—C11—C10	118.2 (6)
Cd1—O1W—H1WB	122 (4)	C12—C11—H11	120.9
H1WA—O1W—H1WB	109 (3)	C10—C11—H11	120.9
Cd1—O2W—H2WA	111 (4)	C13—C12—C11	119.3 (5)
Cd1—O2W—H2WB	109 (4)	C13—C12—H12	120.4
H2WA—O2W—H2WB	104 (3)	C11—C12—H12	120.4
C3—N1—C1	121.2 (4)	C14—C13—C12	118.2 (6)
C3—N1—Cd1	116.7 (3)	C14—C13—H13	120.9
C1—N1—Cd1	121.9 (3)	C12—C13—H13	120.9
C2—N2—C4	119.7 (4)	N4—C14—C13	124.4 (6)
C5—N3—C9	119.1 (4)	N4—C14—H14	117.8
C5—N3—Cd1	121.8 (3)	C13—C14—H14	117.8
C9—N3—Cd1	118.9 (3)	O2—C15—O1	126.9 (5)
C10—N4—C14	116.5 (5)	O2—C15—C3	115.6 (5)
N1—C1—C2	117.9 (5)	O1—C15—C3	117.5 (5)
N1—C1—C5	114.8 (4)	O4—C16—O3	127.6 (5)
C2—C1—C5	127.0 (5)	O4—C16—C4	114.3 (5)
N2—C2—C1	121.6 (5)	O3—C16—C4	118.0 (5)
N2—C2—C10	113.3 (4)

C3—N1—C1—C2	−3.4 (7)	C6—C7—C8—C9	1.0 (8)
Cd1—N1—C1—C2	171.5 (3)	C5—N3—C9—C8	−3.6 (7)
C3—N1—C1—C5	171.2 (4)	Cd1—N3—C9—C8	−178.9 (4)
Cd1—N1—C1—C5	−13.9 (6)	C7—C8—C9—N3	1.2 (8)
C4—N2—C2—C1	−1.1 (8)	C14—N4—C10—C11	−0.9 (8)
C4—N2—C2—C10	176.2 (5)	C14—N4—C10—C2	176.1 (5)
N1—C1—C2—N2	4.7 (7)	N2—C2—C10—N4	−117.2 (5)
C5—C1—C2—N2	−169.2 (5)	C1—C2—C10—N4	60.0 (7)
N1—C1—C2—C10	−172.3 (5)	N2—C2—C10—C11	59.9 (7)
C5—C1—C2—C10	13.8 (8)	C1—C2—C10—C11	−122.9 (6)
C1—N1—C3—C4	−1.2 (7)	N4—C10—C11—C12	1.5 (8)
Cd1—N1—C3—C4	−176.3 (4)	C2—C10—C11—C12	−175.3 (5)
C1—N1—C3—C15	−177.7 (4)	C10—C11—C12—C13	−1.7 (9)
Cd1—N1—C3—C15	7.1 (5)	C11—C12—C13—C14	1.3 (10)
C2—N2—C4—C3	−3.6 (7)	C10—N4—C14—C13	0.4 (9)
C2—N2—C4—C16	−176.7 (5)	C12—C13—C14—N4	−0.7 (10)
N1—C3—C4—N2	4.8 (8)	Cd1—O1—C15—O2	175.2 (4)
C15—C3—C4—N2	−178.9 (5)	Cd1ⁱⁱ—O1—C15—O2	−2.5 (8)
N1—C3—C4—C16	177.2 (5)	Cd1—O1—C15—C3	−6.1 (6)
C15—C3—C4—C16	−6.5 (8)	Cd1ⁱⁱ—O1—C15—C3	176.2 (3)
C9—N3—C5—C6	3.7 (7)	N1—C3—C15—O2	177.9 (4)
Cd1—N3—C5—C6	178.9 (4)	C4—C3—C15—O2	1.5 (8)
C9—N3—C5—C1	−169.7 (4)	N1—C3—C15—O1	−0.9 (7)
Cd1—N3—C5—C1	5.5 (6)	C4—C3—C15—O1	−177.3 (5)
N1—C1—C5—N3	5.2 (6)	Cd1ⁱⁱⁱ—O3—C16—O4	1.6 (8)
C2—C1—C5—N3	179.3 (5)	Cd1ⁱⁱⁱ—O3—C16—C4	177.4 (3)
N1—C1—C5—C6	−167.8 (5)	N2—C4—C16—O4	82.7 (6)
C2—C1—C5—C6	6.3 (9)	C3—C4—C16—O4	−90.0 (7)
N3—C5—C6—C7	−1.5 (8)	N2—C4—C16—O3	−93.7 (6)
C1—C5—C6—C7	171.1 (5)	C3—C4—C16—O3	93.6 (6)
C5—C6—C7—C8	−0.8 (8)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O3^iv	0.82 (2)	2.22 (3)	2.974 (6)	152 (5)
O1W—H1WB···O2^v	0.84 (2)	2.05 (4)	2.805 (6)	150 (7)
O2W—H2WA···O4ⁱ	0.85 (2)	1.88 (3)	2.630 (6)	146 (5)
O2W—H2WB···O2ⁱⁱ	0.85 (2)	1.88 (2)	2.692 (5)	159 (5)
C9—H9···O3^vi	0.94	2.52	3.245 (6)	134
C14—H14···N4^vii	0.94	2.62	3.372 (8)	137

Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) −x+1, −y+1, −z+1; (iv) −x+1, y+1/2, −z+3/2; (v) x, y+1, z; (vi) x, −y+3/2, z−1/2; (vii) −x, −y+1, −z+1.

Acknowledgements

We are grateful to the Swiss National Science Foundation and the University of Neuchâtel for financial support.

References

Alfonso, M. & Stoeckli-Evans, H. (2016a). Acta Cryst. E72, 233–237. Web of Science CSD CrossRef IUCr Journals Google Scholar
Alfonso, M. & Stoeckli-Evans, H. (2016b). Acta Cryst. E72, 1214–1218. CSD CrossRef IUCr Journals Google Scholar
Alfonso, M., Wang, Y. & Stoeckli-Evans, H. (2001). Acta Cryst. C57, 1184–1188. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CSD CrossRef IUCr Journals Google Scholar
Jiao, C., Geng, J., He, C. & Cui, G. (2012). J. Mol. Struct. 1020, 134–141. Web of Science CSD CrossRef CAS Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Neels, A., Alfonso, M., Mantero, D. G. & Stoeckli-Evans, H. (2003). Chimia, 57, 619–622. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stoe & Cie (2004). IPDS-I. Stoe & Cie GmbH, Darmstadt, Germany. Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS 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.