A new cadmium coordination polymer based on 4-amino-4H-1,2,4-triazole

Said, M.; Boughzala, H.

doi:10.1107/S2056989018000464

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Volume 74| Part 2| February 2018| Pages 147-150

https://doi.org/10.1107/S2056989018000464

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A new cadmium coordination polymer based on 4-amino-4H-1,2,4-triazole

Maha Said ^a and Habib Boughzala ^a ^*

^aLaboratoire de Matériaux et Cristallochimie, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Manar II Tunis, Tunisia
^*Correspondence e-mail: habib.boughzala@ipein.rnu.tn

Edited by C. Massera, Università di Parma, Italy (Received 19 December 2017; accepted 8 January 2018; online 12 January 2018)

A new cadmium coordination polymer, poly[bis(4-amino-4H-1,2,4-triazolium) [bis(μ₂-4-amino-4H-1,2,4-triazole-κ²N¹:N²)tetra-μ₂-chlorido-tetrachloridotricadmium(II)] dihydrate], {(C₂H₅N₄)₂[Cd₃Cl₈(C₂H₄N₄)₂]·2H₂O}_n, was synthesized by the reaction of 4-amino-4H-1,2,4 triazole with cadmium(II) chloride in aqueous solution. With an unusual architecture, the crystal structure exhibits two distorted octahedral coordinations of Cd^II joined by edge sharing. The first is composed by four chlorine and two N atoms from the triazole ligands. The second is formed by five Cl atoms and by one N atom from the triazole ligand. The charge of the resulting two-dimensional anionic framework is balanced by the organic triazole cations. The lattice water molecules form a network of hydrogen bonding. N—H⋯Cl and π–π stacking interactions are also involved in the supramolecular network stability.

Keywords: crystal structure; hybrid coordination polymer; cadmium(II); triazole.

CCDC reference: 1810807

1. Chemical context

The last decade has seen a large number of investigations of Cd^II hybrid coordination polymers (HCPs). Indeed, these materials exhibit a wide variety of polymeric frameworks with attractive properties. The coordination sphere of Cd^II is variable, with coordination numbers ranging from four to eight, corresponding to different geometries (tetrahedral, square planar, square pyramidal, trigonal bipyramidal, octahedral, pentagonal bipyramidal, bicapped triangular prismatic and dodecahedral; Li & Du, 2011 ). Many factors should be considered in the self-assembly processes of HCPs, such as the nature of the organic ligands, temperature, pH values, solvents, and so on (Guo et al., 2013 ). The choice of the organic ligands is an important factor that greatly influences the structure and stabilization of the coordination architecture formed (Tao et al., 2000 ; Choi & Jeon, 2003 ). In this regard, organic building units that are based on five-membered N-heterocycles such as 1,2,4 triazole exhibit a strong and typical property of acting as bridging ligands between two metal centres. These bridges can adopt various different geometries, depending on the donor atoms of the ligand and the properties of the metal (Haasnoot et al., 2000 ). The reaction of 4-amino-4H-1,2,4 triazole (NH₂trz) with cadmium dichloride leads to the formation of the title two-dimensional coordination polymer.

2. Structural commentary

The asymmetric unit of the studied compound, completed by the atoms necessary to achieve the coordination around the Cd ions, is represented in Fig. 1. It comprises one and a half Cd^II cations [with Cd2 occupying the special position ( $[{1\over 2}]$ , $[{1\over 2}]$ , $[{1\over 2}]$ )], one triazole molecule (NH₂trz), one triazolium cation (NH₂trzH)⁺, four chloride anions and one lattice water molecule. Cd1 and Cd2 are bridged by the coordinated triazole molecule (NH₂trz) through atoms N1 and N2, and by the two chlorine atoms Cl1 and Cl3.

Figure 1
ORTEP of the asymmetric unit of the studied compound plus the atoms necessary to complete the coordination around the Cd ions. Cd2 is on the special position ( $[{1\over 2}]$ , $[{1\over 2}]$ , $[{1\over 2}]$ ). Displacement ellipsoids are drawn at the at the 50% probability level. [Symmetry codes: (i) x, $[{1\over 2}]$ − y, − $[{1\over 2}]$ + z; (ii) 1 − x, 1 − y, 1 − z.]

Both metals show an octahedral coordination geometry. Cd1 is surrounded by the five chloride anions Cl1, Cl2, Cl3, Cl4, Cl2ⁱ [symmetry code: (i) x, $[{1\over 2}]$ − y, z − $[{1\over 2}]$ ] and the nitrogen N1 of the coordinated triazole ring (NH₂trz). On the other hand, Cd2 is bonded to four equatorial chloride anions (Cl1, Cl3, Cl1ⁱⁱ and Cl3ⁱⁱ) and two axial nitrogen atoms, N2 and N2ⁱⁱ, belonging to the coordinated triazole (NH₂trz) and to its symmetry-related analogue, respectively [symmetry code: (ii) 1 − x, 1 − y, 1 − z). As a result of the bridge formed by atoms N1 and N2 of the triazole ligand, the Cd1⋯Cd2 distance is 3.6145 (7) Å. Selected geometrical parameters are summarized in Table 1, showing that the octahedron around Cd1 is more distorted than the one around Cd2.

Table 1
Selected geometric parameters (Å, °)

Cd1—N1	2.365 (4)	Cd1—Cl1	2.6769 (14)
Cd1—Cl4	2.5120 (14)	Cd2—N2	2.393 (5)
Cd1—Cl2	2.6148 (13)	Cd2—Cl3	2.5874 (16)
Cd1—Cl3	2.6418 (14)	Cd2—Cl1	2.6332 (14)
Cd1—Cl2ⁱ	2.6754 (13)

N1—Cd1—Cl4	174.37 (11)	Cl3—Cd1—Cl1	84.86 (4)
Cl2—Cd1—Cl1	174.60 (4)	Cl3—Cd2—Cl1	86.85 (5)
Symmetry code: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

When symmetry is applied, a Cd₃Cl₈(NH₂trz)₂ building block is formed. These trinuclear units are connected via the chloride ions Cl2 to build up infinite inorganic corrugated sheets in the bc plane, stacked along the a-axis direction (Fig. 2). The triazolium cations (NH₂trzH)⁺ and the water molecules are located in the interlayer space (Fig. 3), interacting with the anionic framework by hydrogen bonds. Thus, the overall three-dimensional network consists of alternate organic–inorganic hybrid layers, responsible for the interesting behaviour of this class of materials.

Figure 2
Crystal packing showing the two-dimensional anionic framework of the title compound.

Figure 3
Corrugated anionic sheets with the non-coordinating triazolium cations and water molecules located in the interlayer space. Displacement ellipsoids are drawn at the 50% probability level.

3. Supramolecular features

The crystal structure of the title compound is mainly stabilized by hydrogen-bonding and π–π stacking interactions. In particular, a number of O—H⋯Cl, O—H⋯N, N—H⋯O and N —H⋯Cl hydrogen bonds is present (Table 2), involving the lattice water molecules, the triazolium cations, the organic ligands and the chlorine anions. These hydrogen bonds connect the organic and inorganic moieties, leading to a self-organized, hydrated hybrid structure.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1Wⁱⁱ—HW2ⁱⁱ⋯Cl1	0.86 (6)	2.68 (7)	3.239 (6)	124 (6)
N4ⁱⁱⁱ—H4Bⁱⁱⁱ⋯Cl3	1.00 (8)	2.60 (7)	3.399 (5)	136 (5)
N8^iv—H8A^iv⋯Cl2	0.85	2.64	3.370 (5)	144
O1Wⁱⁱ—HW1ⁱⁱ⋯Cl4	0.86 (7)	2.67 (8)	3.319 (6)	134 (8)
N8—H8B⋯Cl4	0.90	2.53	3.423 (5)	172
N5^v—H5^v⋯O1W	0.75 (8)	1.97 (8)	2.649 (8)	151 (8)
O1W—HW2⋯N4^vi	0.86 (6)	2.44 (6)	3.247 (9)	157 (6)
Symmetry codes: (ii) -x+1, -y+1, -z+1; (iii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iv) x, y, z+1; (v) $[x-1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (vi) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

The chloride anions around Cd1 and Cd2 form hydrogen bonds both with the amine H atoms of the (NH₂trz) ligands and with the H atoms of the water molecules (Figs. 4 and 5; Table 2): Cl1⋯HW2ⁱⁱ—O1Wⁱⁱ, Cl3⋯H4Bⁱⁱⁱ—N4ⁱⁱⁱ, Cl4⋯HW1ⁱⁱ—O1Wⁱⁱ, Cl4⋯H8B-N8, and Cl2⋯H8A^iv—N8^iv [symmetry codes: (iii) 1 − x, $[{1\over 2}]$ + y, $[{3\over 2}]$ − z; (iv) x, y, 1 + z].

Figure 4
Hydrogen bonds (red dashed lines) involving the chloride anions around Cd1. Displacement ellipsoids are displayed at the 50% probability level. [Symmetry codes: (i) x, $[{1\over 2}]$ − y, − $[{1\over 2}]$ + z; (ii) 1 − x, 1 − y, 1 − z; (iii) 1 − x, $[{1\over 2}]$ + y, $[{3\over 2}]$ − z; (iv) x, y, 1 + z; (vi) x, $[{1\over 2}]$ − y, $[{1\over 2}]$ + z.]

Figure 5
Hydrogen bonds (red dashed lines) involving the chloride anions around Cd2. Displacement ellipsoids are displayed at the 50% probability level. [Symmetry codes: (i) x, $[{1\over 2}]$ − y, − $[{1\over 2}]$ + z; (ii) 1 − x, 1 − y, 1 − z; (iii) 1 − x, $[{1\over 2}]$ + y, $[{3\over 2}]$ − z.]

Besides forming hydrogen bonds with the chloride anions Cl1 and Cl4, the water molecules also interact with the triazole ligands and with the lattice triazolium cations, acting as acceptor and donor, respectively (Fig. 6 and Table 2): O1W⋯H5^v–N5^v and N4^vi⋯HW2—O1W [symmetry codes: (v) x − 1, $[{1\over 2}]$ − y, $[{1\over 2}]$ + z; (vi) x, $[{1\over 2}]$ − y, z + $[{1\over 2}]$ ].

Figure 6
The hydrogen-bonding interactions around a single water molecule involving the chlorine atoms, the (NH₂trz) ligand and the (NH₂trzH)⁺ cation. Displacement ellipsoids are displayed at the 50% probability level. [Symmetry codes: (ii) 1 − x, 1 − y, 1 − z; (v) −1 + x, $[{1\over 2}]$ − y, $[{1\over 2}]$ + z; (vi) x, $[{1\over 2}]$ − y, $[{1\over 2}]$ + z.]

Finally, the coordinated triazole rings (NH₂trz) are connected along the c-axis direction through π–π stacking interactions, with a centroid–centroid distance of 3.761 (7) Å.

4. Database survey

Recently, a great deal of attention has been paid to the rational design and synthesis of new hybrid coordination polymers (HCPs) composed of metal ions and bridging ligands due to their fascinating structural diversity and their potential application as functional materials (Xiong et al., 2001 ; Liao et al., 2004 ; Gao et al., 2008 ). These coordination polymers exhibit a wide range of infinite zero- to three-dimensional frameworks with interesting structural features, which result from coordination bonding, hydrogen-bonding and aromatic π–π stacking interactions as well as van der Waals forces (Su et al., 2003 ).

A search of the latest version of the Cambridge Structural Database (Version 5.38; Groom et al., 2016 ) based on the organic fragment `4-amino-4H-1,2,4-triazole' of the studied compound yielded 70 hits. The structure of the chloro-cadmate PEPWIR (Zhai et al., 2006 ) is probably the nearest to that of the title compound, even if it lacks the water molecules of crystallization and the protonated triazole cations. This is probably due to the difference in the stoichiometry of the initial reagents and to the solvent used in the chemical synthesis. Two other related compounds comprising 4-amino-4H-1,2,4-triazole in combination with chloride ligands are the coordination polymer ROFJED (Wang et al., 2014 ) and the discrete complex GAVFEP (Xuan-Wen, 2005 ).

5. Synthesis and crystallization

The compound was prepared by the reaction of 4-amino-4H-1,2,4 triazole and CdCl₂·H₂O (molar ratio 1:1) in an equal volume of water and ethanol (10 ml) mixed with 2 ml of hydrochloric acid (37%). The solution was stirred for 1 h. Colourless crystals suitable for X-ray diffraction were grown in two weeks by slow evaporation at room temperature.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. Atoms H1, H2 and H3 were placed in calculated positions and refined using a riding model: C—H = 0.93 Å with U_iso(H) = 1.2U_eq(C). The other hydrogen atoms were found in the difference-Fourier map. The coordinates of H8A, H8B and H4A of the amine terminal groups were kept fixed, with U_i_so(H)= 0.05.

Table 3
Experimental details

Crystal data
Chemical formula	(C₂H₅N₄)₂[Cd₃Cl₈(C₂H₄N₄)₂]·2H₂O
M_r	995.21
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	298
a, b, c (Å)	12.685 (3), 15.498 (3), 7.375 (2)
β (°)	97.12 (3)
V (Å³)	1438.6 (6)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	2.98
Crystal size (mm)	0.71 × 0.21 × 0.21

Data collection
Diffractometer	Enraf–Nonius CAD-4
Absorption correction	ψ scan (North et al., 1968 )
T_min, T_max	0.799, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	3670, 3136, 2654
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.638

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.040, 0.123, 1.06
No. of reflections	3136
No. of parameters	190
No. of restraints	5
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.58, −1.99
Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994 ), XCAD4 (Harms & Wocadlo, 1995 $[Harms, K. & Wocadlo, S. (1995). XCAD4. Program for Processing CAD-4 Diffractometer Data. University of Marburg, Germany.]$ ), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), DIAMOND (Brandenburg, 2006 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1810807

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989018000464/xi2006sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018000464/xi2006Isup2.hkl

checkCIF report

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Poly[bis(4-amino-4H-1,2,4-triazolium) [bis(µ₂-4-amino-4H-1,2,4-triazole-κ²N¹:N²)tetra-µ₂-chlorido-tetrachloridotricadmium(II)] dihydrate] top

Crystal data top

(C₂H₅N₄)₂[Cd₃Cl₈(C₂H₄N₄)₂]·2H₂O	F(000) = 956
M_r = 995.21	D_x = 2.298 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 12.685 (3) Å	Cell parameters from 25 reflections
b = 15.498 (3) Å	θ = 10–15°
c = 7.375 (2) Å	µ = 2.98 mm⁻¹
β = 97.12 (3)°	T = 298 K
V = 1438.6 (6) Å³	Prism, colourless
Z = 2	0.71 × 0.21 × 0.21 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	R_int = 0.032
Radiation source: Enraf Nonius FR590	θ_max = 27.0°, θ_min = 2.1°
non–profiled ω/2τ scans	h = −16→16
Absorption correction: ψ scan (North et al., 1968)	k = −19→1
T_min = 0.799, T_max = 1.000	l = −9→1
3670 measured reflections	2 standard reflections every 120 min
3136 independent reflections	intensity decay: 8%
2654 reflections with I > 2σ(I)

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.040	w = 1/[σ²(F_o²) + (0.0848P)² + 1.0345P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.123	(Δ/σ)_max = 0.001
S = 1.06	Δρ_max = 1.58 e Å⁻³
3136 reflections	Δρ_min = −1.99 e Å⁻³
190 parameters	Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
5 restraints	Extinction coefficient: 0.0041 (7)

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.

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 (Å²) top

	x	y	z	U_iso*/U_eq
Cd1	0.72922 (3)	0.36225 (2)	0.60671 (4)	0.02384 (16)
Cd2	0.5000	0.5000	0.5000	0.02726 (18)
Cl1	0.65520 (10)	0.45547 (8)	0.31268 (16)	0.0291 (3)
Cl2	0.78296 (10)	0.26723 (9)	0.89644 (16)	0.0307 (3)
Cl3	0.63396 (12)	0.47886 (9)	0.79095 (17)	0.0379 (3)
Cl4	0.91217 (11)	0.42626 (9)	0.6250 (2)	0.0369 (3)
N1	0.5591 (3)	0.2978 (3)	0.5599 (6)	0.0271 (9)
N2	0.4709 (4)	0.3474 (3)	0.5015 (6)	0.0300 (9)
N3	0.4303 (4)	0.2130 (3)	0.4573 (6)	0.0284 (9)
N4	0.3704 (5)	0.1390 (3)	0.3952 (8)	0.0427 (12)
N5	1.0964 (5)	0.2603 (4)	0.1439 (8)	0.0406 (11)
N6	1.1503 (5)	0.3284 (4)	0.0808 (9)	0.0552 (15)
N7	0.9940 (4)	0.3688 (3)	0.1463 (6)	0.0341 (10)
N8	0.9074 (4)	0.4233 (3)	0.1599 (6)	0.0388 (11)
C1	0.5314 (4)	0.2172 (3)	0.5326 (7)	0.0301 (10)
H1	0.5755	0.1699	0.5613	0.036*
C2	0.3953 (4)	0.2949 (4)	0.4392 (8)	0.0326 (11)
H2	0.3273	0.3114	0.3895	0.039*
C3	1.0035 (5)	0.2844 (4)	0.1816 (8)	0.0371 (12)
H3	0.9528	0.2493	0.2253	0.044*
C4	1.0865 (6)	0.3931 (4)	0.0848 (11)	0.0481 (16)
O1W	0.1792 (5)	0.3900 (4)	0.5653 (10)	0.0663 (15)
H4	1.103 (5)	0.450 (4)	0.066 (9)	0.038 (17)*
H5	1.127 (6)	0.219 (5)	0.158 (11)	0.05 (2)*
H8A	0.8524	0.4002	0.1015	0.050*
H8B	0.9153	0.4271	0.2827	0.050*
H4A	0.4298	0.0977	0.3612	0.050*
H4B	0.350 (6)	0.120 (4)	0.516 (11)	0.045 (19)*
HW2	0.237 (4)	0.396 (5)	0.638 (9)	0.07 (3)*
HW1	0.142 (6)	0.435 (4)	0.580 (14)	0.11 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.0255 (2)	0.0249 (2)	0.0204 (2)	0.00043 (12)	0.00023 (14)	0.00166 (12)
Cd2	0.0335 (3)	0.0216 (3)	0.0261 (3)	0.00527 (19)	0.0016 (2)	0.00027 (18)
Cl1	0.0363 (6)	0.0285 (6)	0.0229 (5)	0.0036 (5)	0.0046 (5)	0.0044 (4)
Cl2	0.0347 (6)	0.0341 (7)	0.0227 (6)	−0.0022 (5)	0.0013 (5)	0.0100 (5)
Cl3	0.0507 (8)	0.0372 (7)	0.0235 (6)	0.0143 (6)	−0.0041 (5)	−0.0085 (5)
Cl4	0.0327 (7)	0.0366 (7)	0.0410 (7)	−0.0101 (5)	0.0027 (5)	−0.0007 (6)
N1	0.026 (2)	0.026 (2)	0.029 (2)	0.0019 (16)	0.0020 (16)	0.0019 (16)
N2	0.032 (2)	0.029 (2)	0.028 (2)	0.0029 (18)	0.0022 (17)	−0.0003 (17)
N3	0.040 (2)	0.025 (2)	0.022 (2)	−0.0059 (18)	0.0095 (17)	−0.0032 (15)
N4	0.054 (3)	0.034 (3)	0.042 (3)	−0.020 (2)	0.011 (2)	−0.009 (2)
N5	0.046 (3)	0.034 (3)	0.041 (3)	−0.001 (2)	0.003 (2)	0.000 (2)
N6	0.054 (3)	0.047 (3)	0.071 (4)	0.002 (3)	0.031 (3)	0.005 (3)
N7	0.035 (2)	0.043 (3)	0.025 (2)	−0.0025 (19)	0.0072 (18)	−0.0042 (18)
N8	0.044 (3)	0.034 (2)	0.040 (3)	−0.002 (2)	0.009 (2)	−0.006 (2)
C1	0.034 (3)	0.025 (2)	0.031 (3)	0.003 (2)	0.002 (2)	0.002 (2)
C2	0.030 (3)	0.034 (3)	0.034 (3)	−0.001 (2)	0.003 (2)	−0.001 (2)
C3	0.042 (3)	0.037 (3)	0.031 (3)	−0.007 (2)	0.001 (2)	0.007 (2)
C4	0.051 (4)	0.037 (3)	0.061 (4)	−0.007 (3)	0.023 (3)	0.000 (3)
O1W	0.057 (3)	0.043 (3)	0.095 (5)	−0.011 (3)	−0.002 (3)	−0.002 (3)

Geometric parameters (Å, º) top

Cd1—N1	2.365 (4)	N4—H4A	1.0400
Cd1—Cl4	2.5120 (14)	N4—H4B	1.01 (8)
Cd1—Cl2	2.6148 (13)	N5—C3	1.299 (9)
Cd1—Cl3	2.6418 (14)	N5—N6	1.369 (8)
Cd1—Cl2ⁱ	2.6754 (13)	N5—H5	0.75 (8)
Cd1—Cl1	2.6769 (14)	N6—C4	1.292 (9)
Cd2—N2ⁱⁱ	2.393 (5)	N7—C3	1.336 (7)
Cd2—N2	2.393 (5)	N7—C4	1.362 (8)
Cd2—Cl3	2.5874 (16)	N7—N8	1.399 (7)
Cd2—Cl3ⁱⁱ	2.5875 (16)	N8—H8A	0.850
Cd2—Cl1	2.6332 (14)	N8—H8B	0.900
Cd2—Cl1ⁱⁱ	2.6333 (14)	C1—H1	0.9300
N1—C1	1.306 (7)	C2—H2	0.9300
N1—N2	1.382 (6)	C3—H3	0.9300
N2—C2	1.297 (7)	C4—H4	0.92 (6)
N3—C1	1.335 (7)	O1W—HW2	0.862 (10)
N3—C2	1.346 (7)	O1W—HW1	0.857 (10)
N3—N4	1.419 (6)

N1—Cd1—Cl4	174.37 (11)	N1—N2—Cd2	115.6 (3)
Cl4—Cd1—Cl3	100.40 (5)	C1—N3—C2	106.4 (4)
Cl2—Cd1—Cl3	93.13 (5)	C1—N3—N4	128.4 (5)
N1—Cd1—Cl2ⁱ	83.80 (11)	C2—N3—N4	125.0 (5)
Cl4—Cd1—Cl2ⁱ	91.57 (5)	N3—N4—H4A	102.00
Cl2—Cd1—Cl2ⁱ	89.53 (3)	N3—N4—H4B	98 (4)
N1—Cd1—Cl1	83.54 (11)	H4A—N4—H4B	108.00
Cl4—Cd1—Cl1	93.40 (5)	C3—N5—N6	110.8 (5)
Cl2—Cd1—Cl1	174.60 (4)	C3—N5—H5	133 (6)
Cl3—Cd1—Cl1	84.86 (4)	N6—N5—H5	116 (6)
Cl2ⁱ—Cd1—Cl1	91.39 (4)	C4—N6—N5	104.5 (6)
N2ⁱⁱ—Cd2—Cl3	92.46 (11)	C3—N7—C4	106.0 (5)
N2—Cd2—Cl3	87.54 (12)	C3—N7—N8	129.0 (5)
N2ⁱⁱ—Cd2—Cl3ⁱⁱ	87.54 (11)	C4—N7—N8	125.0 (5)
N2—Cd2—Cl3ⁱⁱ	92.46 (12)	N7—N8—H8A	108.00
N2ⁱⁱ—Cd2—Cl1	97.50 (11)	N7—N8—H8B	97.00
N2—Cd2—Cl1	82.50 (11)	H8A—N8—H8B	121.00
Cl3—Cd2—Cl1	86.85 (5)	N1—C1—N3	109.7 (5)
Cl3ⁱⁱ—Cd2—Cl1	93.15 (5)	N1—C1—H1	125.2
N2ⁱⁱ—Cd2—Cl1ⁱⁱ	82.50 (11)	N3—C1—H1	125.2
N2—Cd2—Cl1ⁱⁱ	97.50 (11)	N2—C2—N3	109.7 (5)
Cl3—Cd2—Cl1ⁱⁱ	93.15 (5)	N2—C2—H2	125.1
Cl3ⁱⁱ—Cd2—Cl1ⁱⁱ	86.85 (5)	N3—C2—H2	125.1
Cd2—Cl1—Cd1	85.79 (4)	N5—C3—N7	107.6 (5)
Cd1—Cl2—Cd1ⁱⁱⁱ	146.79 (5)	N5—C3—H3	126.2
Cd2—Cl3—Cd1	87.44 (4)	N7—C3—H3	126.2
C1—N1—N2	107.0 (4)	N6—C4—N7	111.1 (6)
C1—N1—Cd1	130.5 (3)	N6—C4—H4	126 (4)
N2—N1—Cd1	120.0 (3)	N7—C4—H4	122 (4)
C2—N2—N1	107.2 (4)	HW2—O1W—HW1	106 (3)
C2—N2—Cd2	136.6 (4)

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
O1Wⁱⁱ—HW2ⁱⁱ···Cl1	0.86 (6)	2.68 (7)	3.239 (6)	124 (6)
N4^iv—H4B^iv···Cl3	1.00 (8)	2.60 (7)	3.399 (5)	136 (5)
N8^v—H8A^v···Cl2	0.85	2.64	3.370 (5)	144
O1Wⁱⁱ—HW1ⁱⁱ···Cl4	0.86 (7)	2.67 (8)	3.319 (6)	134 (8)
N8—H8B···Cl4	0.90	2.53	3.423 (5)	172
N5^vi—H5^vi···O1W	0.75 (8)	1.97 (8)	2.649 (8)	151 (8)
O1W—HW2···N4ⁱⁱⁱ	0.86 (6)	2.44 (6)	3.247 (9)	157 (6)

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

Acknowledgements

We acknowledge the assistance of the staff of the Tunisian Laboratory of Materials and Crystallography during the data collection.

Funding information

Funding for this research was provided by: Université de Tunis El Manar (Tunisia).

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