Crystal structure of poly[bis­(μ-2-amino-4,5-di­cyano­imidazolato-κ2N1:N3)-trans-bis­(N,N′-di­methyl­formamide-κO)cadmium]

Zhu, J.-L.; Jiang, G. -Q.; Guo, X.-Q.; Tang, Y.-F.; Wang, M.

doi:10.1107/S2056989015014516

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 71| Part 9| September 2015| Pages 1022-1025

https://doi.org/10.1107/S2056989015014516

Open

access

Crystal structure of poly[bis(μ-2-amino-4,5-dicyanoimidazolato-κ²N¹:N³)-trans-bis(N,N′-dimethylformamide-κO)cadmium]

Jin-Li Zhu,^a ^* Guo -Qing Jiang,^a Xiao-Qing Guo,^b Yan-Feng Tang ^a and Miao Wang ^a

^aCollege of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, People's Republic of China, and ^bSchool of Textile and Clothing, Nantong University, Nantong 226019, People's Republic of China
^*Correspondence e-mail: 18260599283@163.com

Edited by M. Weil, Vienna University of Technology, Austria (Received 13 July 2015; accepted 1 August 2015; online 12 August 2015)

In the title structure, [Cd(C₅H₂N₅)₂(C₃H₇NO)₂]_n or [Cd(adci)₂(DMF)₂]_n, the Cd²⁺ ion is located on a twofold rotation axis and is six-coordinated in a CdN₄O₂ manner by four imidazole N atoms of four symmetry-related 2-amino-4,5-dicyanoimidazolate (adci) anions in the equatorial plane and by two O atoms of symmetry-related N,N-dimethylformamide (DMF) ligands in axial positions. The adci⁻ anions bridge adjacent Cd²⁺ ions [shortest Cd⋯Cd separation = 6.733 (3) Å] into a layered coordination polymer extending parallel to (001). The primary amino group and the non-coordinating cyano groups of adci⁻ anions are involved in hydrogen-bonding interactions with DMF ligands to stabilize the crystal structure.

Keywords: crystal structure; 2-amino-4,5-dicyanoimidazole; metal–organic framework; cadmium coordination polymer; hydrogen bonding.

CCDC reference: 1416545

1. Chemical context

Porous materials such as metal-organic frameworks (MOFs) combining advantages of both organic and inorganic components have emerged as a unique class of crystalline solid-state materials today due to their potential applications in gas adsorption and separation (Collins & Zhou, 2007 ), catalysis (Gu et al., 2012 ) and analytical chemistry (Mondal et al., 2013 ). As a branch of MOFs, zeolitic imidazolate frameworks (ZIFs), which are topologically related to inorganic zeolites, commonly reveal high thermal and chemical stability (Eddaoudi et al., 2015 ). Bridging N-donor ligands such as 2-substituted 4,5-dicyanoimidazole (dci) molecules are often used to synthesize ZIFs (Sava et al., 2009 ; Mondal et al., 2014 ). In addition, the cyano group of dci can generate carboxylate- (Orcajo et al., 2014 ) or tetrazole-based (Xiong et al., 2002 ) ligands by in-situ ligand reactions.

We chose a rigid planar ligand, viz. 2-amino-4,5-dicyanoimidazole (adci), and Cd²⁺ that exhibits strong coordination capabilities for imidazolates, to prepare new metal-organic polymers and report here the structure of the title compound, [Cd(C₅H₂N₅)₂(C₃H₇NO)₂]_n, or [Cd(adci)₂(DMF)₂]_n (DMF is dimethylformamide), (I).

2. Structural commentary

Complex (I) is a mononuclear cadmium coordination polymer, in which the central Cd²⁺ ion exhibits a tetragonally distorted octahedral coordination environment (Fig. 1). The asymmetric unit of (I) comprises one Cd²⁺ ion located on a twofold rotation axis, one 2-amino-4,5-dicyanoimidazolate ion and one DMF ligand, both in general positions. The Cd²⁺ ion has an N₄O₂ coordination set defined by four N atoms of four symmetry-related adci⁻ anions in the equatorial plane and by two oxygen atoms of two symmetry-related DMF ligands in axial positions. The Cd—N bond lengths [2.339 (4) and 2.353 (4) Å] and Cd—O bond length [2.322 (4) Å] fall in normal ranges (Groom & Allen, 2014 ). Each adci⁻ anion bridges two adjacent Cd²⁺ ions in a bis-monodentate mode through two imidazole N atoms whereas the DMF molecules serve as terminal ligands. Thus, four Cd²⁺ ions and four bridging adci⁻ ligands generate a square motif aligned parallel to (001), as shown in Fig. 2. The Cd⋯Cd distance along the edge of the square is 6.733 (3) Å, which is similar to previously reported structures (Li et al., 2010 ; Wang et al., 2010 ).

Figure 1
The coordination sphere around Cd²⁺ in the structure of (I)

, with displacement ellipsoids drawn at the 30% probability level. H atoms bonded to C and N atoms have been omitted for clarity. [Symmetry code: (A) 2 − x, y, $[{3\over 2}]$ − z.].

Figure 2
The two-dimensional network in the structure of (I)

, viewed perpendicular to the ab plane. Colour key: Cd steel, N blue, H grey, C light grey ande O red.

3. Supramolecular features

Complex (I) possesses various hydrogen-bonding interactions (Table 1). The amino group and the non-coordinating cyano N atoms are involved in hydrogen-bonding interactions with DMF ligands to stabilize the crystal structure. In the 2D metal-organic network, intermolecular N1—H1A⋯O1 hydrogen bonds between the primary amine group of adci⁻ and the O atoms of an DMF ligand as well as C7—H7C⋯N5 interactions between the methyl C atoms of DMF and the non-coordinating N atoms of the cyano group of an adci⁻ anion play a crucial role in directing and stabilizing the assembly of the supramolecular structure (Kim et al., 2015 ; Sava et al., 2009), as shown in Fig. 3a. The layers are packed together by weak C7—H7B⋯N4 interactions, involving the methyl C atom of DMF and another N atom of a cyano group (Fig. 3b). The lengths of these three hydrogen bonds fall in or approach the range (3.2–4.0 Å) of weak hydrogen-bonding interactions (Desiraju, 1996 ; Steed & Atwood, 2000 ).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1ⁱ	0.86	2.45	3.187 (6)	144
C7—H7C⋯N5ⁱ	0.96	2.68	3.429 (12)	135
C7—H7B⋯N4ⁱⁱ	0.96	2.65	3.496 (11)	148
Symmetry codes: (i) $[-x+{\script{3\over 2}}, y+{\script{1\over 2}}, z]$ ; (ii) $[x, -y, z-{\script{1\over 2}}]$ .

Figure 3
(a) View of two kinds of hydrogen bonds in the layers. Dashed lines represent C—H⋯N (green) and N—H⋯O (red) hydrogen bonds, respectively. (b) The crystal packing between the layers in the title structure. C—H⋯N hydrogen-bonding interactions are drawn as red dashed lines. [Symmetry codes: (a) $[{3\over 2}]$ − x, − $[{1\over 2}]$ + y, z; (b) $[{3\over 2}]$ − x, $[{1\over 2}]$ + y, z; (c) x, −y, − $[{1\over 2}]$ + z].

4. Database survey

The cyano groups of the dci ligands exhibit a strong electron-withdrawing effect. Consequently, the formation of anionic species is relatively straightforward (Prasad et al., 1999 ) and 4,5-dicyanoimidazoles can be used in the preparation of coordination frameworks with different metal ions. However, reports on systems with 2-amino-4,5-dicyanoimidazole, a novel rigid planar ligand with five potential coordination sites, are rather scarce. A search in the Cambridge Structural Database (Version 5.27, May 2014; Groom & Allen, 2014) for 4,5-dicyanoimidazole revealed eleven complexes with 2-substituted 4,5-imidazoledicarbonitrile ligands. An unprecedented SHG-active silver-containing MOF with a rare 10³ topology has been reported (Yang et al., 2013 ), as well as the synthesis and fluorescent properties of a 3D heterometallic polymeric complex {[K[Cd(dci)₂(H₂O)₆]Cl]}_n (Li et al., 2010), and of {[Zn₂(IMDN)₄(H₂O)₃]·3H₂O₃}_n and [Co(IMDN)₂(H₂O)₂]_n (Hu et al., 2013 ) (IMDN is 2H-imidazole-4,5-dicarbonitrile) with chain structures. However, the coordination modes of the imidazoles in these complexes are different.

5. Synthesis and crystallization

Compound (I) was synthesized as follows: adci (0.0266 g, 0.2 mmol) and HNO₃ (0.2 ml, 3.5 M in DMF) were mixed in 2 ml DMF. After stirring for 0.5 h, Cd(NO₃)₂·4H₂O (0.0308 g, 0.1 mmol) in 6 ml methanol was added dropwise. The mixture was further stirred for another hour and then filtrated. The filtrate was kept at ambient temperature. After about three weeks, yellow block-shaped crystals of (I) suitable for single X-ray diffraction were obtained. Yield: 0.0224 g (43% based on Cd). FT–IR (KBr, cm⁻¹): 3436, 3346, 2930, 2217, 1658, 1525, 1486, 1444, 1385, 1328, 1305, 1115, 675.

6. Refinement

Crystal data, data collection and refinement details are summarized in Table 2. Hydrogen atoms of the organic ligands were placed in idealized positions, with d(C—H) = 0.93 Å for sp²-bound H atoms and U_iso(H) = 1.2U_eq(C), and d(C—H) = 0.96 Å for methyl H atoms and U_iso(H) = 1.5U_eq(C). H atoms of the amino group were located from a difference map and were refined with d(N—H) = 0.86 Å and U_iso(H) = 1.2U_eq(N).

Table 2
Experimental details

Crystal data
Chemical formula	[Cd(C₅H₂N₅)₂(C₃H₇NO)₂]
M_r	522.83
Crystal system, space group	Orthorhombic, Pbcn
Temperature (K)	296
a, b, c (Å)	9.8438 (2), 9.1897 (2), 22.8948 (4)
V (Å³)	2071.10 (7)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.10
Crystal size (mm)	0.18 × 0.12 × 0.10

Data collection
Diffractometer	Bruker SMART APEX CCD area detector
Absorption correction	Multi-scan (SADABS; Bruker, 2008 )
T_min, T_max	0.854, 0.896
No. of measured, independent and observed [I > 2σ(I)] reflections	9497, 2386, 1741
R_int	0.022
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.159, 1.07
No. of reflections	2353
No. of parameters	143
No. of restraints	96
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.71, −0.66
Computer programs: SMART and SAINT (Bruker, 2008), SHELXTL (Sheldrick, 2008 ), Mercury (Macrae et al. (2006 ) and DIAMOND (Brandenburg, 2006 ).

Supporting information

CCDC reference: 1416545

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2056989015014516/wm5187sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989015014516/wm5187Isup2.hkl

checkCIF report

Computing details top

Data collection: SMART (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008), Mercury (Macrae et al. (2006) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Poly[bis(µ-2-amino-4,5-dicyanoimidazolato-κ²N¹:N³)-trans-bis(N,N'-dimethylformamide-κO)cadmium] top

Crystal data top

[Cd(C₅H₂N₅)₂(C₃H₇NO)₂]	F(000) = 1048
M_r = 522.83	D_x = 1.677 Mg m⁻³
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	θ = 3.5–27.5°
a = 9.8438 (2) Å	µ = 1.10 mm⁻¹
b = 9.1897 (2) Å	T = 296 K
c = 22.8948 (4) Å	Block, yellow
V = 2071.10 (7) Å³	0.18 × 0.12 × 0.10 mm
Z = 4

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	2386 independent reflections
Radiation source: fine-focus sealed tube	1741 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.022
phi and ω scans	θ_max = 27.5°, θ_min = 4.1°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −12→11
T_min = 0.854, T_max = 0.896	k = −11→11
9497 measured reflections	l = −29→26

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.159	H-atom parameters constrained
S = 1.07	w = 1/[σ²(F_o²) + (0.0999P)² + 4.109P] where P = (F_o² + 2F_c²)/3
2353 reflections	(Δ/σ)_max < 0.001
143 parameters	Δρ_max = 1.71 e Å⁻³
96 restraints	Δρ_min = −0.66 e Å⁻³

Special details top

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

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
Cd1	1.0000	0.11224 (5)	0.7500	0.0180 (2)
N1	0.8425 (4)	0.4650 (5)	0.71416 (18)	0.0327 (10)
H1A	0.8043	0.5387	0.6978	0.039*
H1B	0.9243	0.4416	0.7050	0.039*
N2	0.8289 (4)	0.2699 (4)	0.78205 (17)	0.0269 (9)
C4	0.7391 (6)	0.1135 (5)	0.8626 (2)	0.0360 (12)
O1	0.9090 (4)	0.1297 (4)	0.65667 (17)	0.0449 (10)
N3	1.1454 (4)	−0.0840 (4)	0.72898 (18)	0.0224 (8)
C1	0.7732 (6)	0.3852 (5)	0.75474 (18)	0.0235 (10)
C2	0.7281 (5)	0.2249 (5)	0.81951 (18)	0.0258 (9)
C3	1.1166 (4)	−0.1874 (5)	0.6876 (2)	0.0234 (9)
N6	0.9069 (5)	0.1975 (7)	0.5616 (2)	0.0516 (13)
N5	0.8982 (5)	−0.2271 (6)	0.6291 (3)	0.0571 (15)
N4	0.7418 (7)	0.0315 (6)	0.9000 (2)	0.0651 (17)
C5	0.9921 (5)	−0.2038 (6)	0.6565 (2)	0.0308 (11)
C6	0.9373 (9)	0.2022 (10)	0.6174 (3)	0.0700 (18)
H6	0.9931	0.2801	0.6272	0.084*
C8	0.9492 (13)	0.3011 (17)	0.5189 (5)	0.122 (3)
H8A	0.9115	0.3947	0.5282	0.183*
H8B	0.9178	0.2711	0.4811	0.183*
H8C	1.0465	0.3073	0.5187	0.183*
C7	0.8193 (12)	0.0771 (13)	0.5425 (5)	0.113 (3)
H7A	0.8668	−0.0134	0.5472	0.169*
H7B	0.7959	0.0902	0.5022	0.169*
H7C	0.7381	0.0758	0.5657	0.169*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.0143 (3)	0.0181 (3)	0.0217 (3)	0.000	0.00059 (15)	0.000
N1	0.023 (2)	0.032 (2)	0.043 (2)	0.0050 (18)	0.0117 (18)	0.0122 (19)
N2	0.0247 (19)	0.029 (2)	0.027 (2)	0.0072 (17)	0.0029 (15)	0.0036 (16)
C4	0.043 (3)	0.033 (3)	0.032 (2)	0.017 (2)	0.010 (2)	0.0043 (19)
O1	0.048 (2)	0.060 (2)	0.0270 (18)	0.0003 (19)	−0.0062 (17)	0.0052 (16)
N3	0.0155 (18)	0.024 (2)	0.0272 (18)	0.0032 (16)	0.0015 (16)	−0.0037 (17)
C1	0.022 (2)	0.024 (2)	0.024 (2)	0.0054 (17)	−0.0030 (16)	−0.0004 (16)
C2	0.029 (2)	0.026 (2)	0.023 (2)	0.0059 (19)	0.0019 (18)	0.0001 (17)
C3	0.021 (2)	0.021 (2)	0.028 (2)	−0.0009 (17)	0.0007 (18)	−0.0001 (17)
N6	0.052 (3)	0.076 (3)	0.027 (2)	0.014 (3)	−0.006 (2)	0.005 (2)
N5	0.036 (3)	0.069 (4)	0.067 (4)	−0.004 (3)	−0.019 (3)	−0.021 (3)
N4	0.100 (5)	0.054 (3)	0.041 (3)	0.030 (3)	0.022 (3)	0.018 (2)
C5	0.029 (3)	0.028 (3)	0.035 (3)	−0.0021 (19)	0.001 (2)	−0.008 (2)
C6	0.072 (4)	0.084 (4)	0.054 (3)	0.025 (4)	0.004 (3)	0.007 (3)
C8	0.143 (7)	0.138 (8)	0.085 (6)	0.023 (7)	0.016 (6)	0.036 (6)
C7	0.116 (7)	0.130 (7)	0.092 (6)	0.023 (6)	−0.024 (5)	−0.032 (6)

Geometric parameters (Å, º) top

Cd1—O1ⁱ	2.322 (4)	C1—N3ⁱⁱⁱ	1.342 (7)
Cd1—O1	2.322 (4)	C2—C3ⁱⁱⁱ	1.371 (6)
Cd1—N2ⁱ	2.339 (4)	C3—C2ⁱⁱ	1.371 (6)
Cd1—N2	2.339 (4)	C3—C5	1.426 (6)
Cd1—N3ⁱ	2.353 (4)	N6—C6	1.311 (9)
Cd1—N3	2.353 (4)	N6—C8	1.427 (13)
N1—C1	1.366 (6)	N6—C7	1.469 (12)
N1—H1A	0.8600	N5—C5	1.136 (7)
N1—H1B	0.8600	C6—H6	0.9300
N2—C1	1.347 (6)	C8—H8A	0.9600
N2—C2	1.375 (6)	C8—H8B	0.9600
C4—N4	1.141 (6)	C8—H8C	0.9600
C4—C2	1.426 (6)	C7—H7A	0.9600
O1—C6	1.154 (8)	C7—H7B	0.9600
N3—C1ⁱⁱ	1.342 (7)	C7—H7C	0.9600
N3—C3	1.371 (6)

O1ⁱ—Cd1—O1	172.1 (2)	N3ⁱⁱⁱ—C1—N1	123.0 (4)
O1ⁱ—Cd1—N2ⁱ	88.18 (14)	N2—C1—N1	122.3 (5)
O1—Cd1—N2ⁱ	86.91 (14)	C3ⁱⁱⁱ—C2—N2	109.1 (4)
O1ⁱ—Cd1—N2	86.91 (14)	C3ⁱⁱⁱ—C2—C4	124.4 (4)
O1—Cd1—N2	88.18 (14)	N2—C2—C4	126.3 (4)
N2ⁱ—Cd1—N2	103.5 (2)	C2ⁱⁱ—C3—N3	108.9 (4)
O1ⁱ—Cd1—N3ⁱ	95.71 (15)	C2ⁱⁱ—C3—C5	124.5 (4)
O1—Cd1—N3ⁱ	90.38 (15)	N3—C3—C5	126.6 (4)
N2ⁱ—Cd1—N3ⁱ	167.68 (14)	C6—N6—C8	125.3 (9)
N2—Cd1—N3ⁱ	88.42 (14)	C6—N6—C7	116.6 (8)
O1ⁱ—Cd1—N3	90.38 (15)	C8—N6—C7	118.0 (8)
O1—Cd1—N3	95.71 (15)	N5—C5—C3	173.8 (6)
N2ⁱ—Cd1—N3	88.42 (13)	O1—C6—N6	133.3 (9)
N2—Cd1—N3	167.68 (15)	O1—C6—H6	113.4
N3ⁱ—Cd1—N3	79.89 (19)	N6—C6—H6	113.4
C1—N1—H1A	120.0	N6—C8—H8A	109.5
C1—N1—H1B	120.0	N6—C8—H8B	109.5
H1A—N1—H1B	120.0	H8A—C8—H8B	109.5
C1—N2—C2	103.4 (4)	N6—C8—H8C	109.5
C1—N2—Cd1	129.4 (3)	H8A—C8—H8C	109.5
C2—N2—Cd1	122.0 (3)	H8B—C8—H8C	109.5
N4—C4—C2	174.4 (6)	N6—C7—H7A	109.5
C6—O1—Cd1	131.7 (6)	N6—C7—H7B	109.5
C1ⁱⁱ—N3—C3	103.9 (4)	H7A—C7—H7B	109.5
C1ⁱⁱ—N3—Cd1	132.5 (3)	N6—C7—H7C	109.5
C3—N3—Cd1	123.1 (3)	H7A—C7—H7C	109.5
N3ⁱⁱⁱ—C1—N2	114.7 (4)	H7B—C7—H7C	109.5

O1ⁱ—Cd1—N2—C1	136.9 (5)	N2ⁱ—Cd1—N3—C3	−116.7 (4)
O1—Cd1—N2—C1	−36.8 (5)	N2—Cd1—N3—C3	78.0 (8)
N2ⁱ—Cd1—N2—C1	49.6 (4)	N3ⁱ—Cd1—N3—C3	59.4 (3)
N3ⁱ—Cd1—N2—C1	−127.3 (5)	C2—N2—C1—N3ⁱⁱⁱ	−0.9 (5)
N3—Cd1—N2—C1	−145.5 (6)	Cd1—N2—C1—N3ⁱⁱⁱ	153.2 (3)
O1ⁱ—Cd1—N2—C2	−73.1 (4)	C2—N2—C1—N1	178.5 (4)
O1—Cd1—N2—C2	113.1 (4)	Cd1—N2—C1—N1	−27.4 (7)
N2ⁱ—Cd1—N2—C2	−160.5 (4)	C1—N2—C2—C3ⁱⁱⁱ	1.1 (5)
N3ⁱ—Cd1—N2—C2	22.7 (3)	Cd1—N2—C2—C3ⁱⁱⁱ	−155.5 (3)
N3—Cd1—N2—C2	4.4 (9)	C1—N2—C2—C4	−174.0 (5)
O1ⁱ—Cd1—O1—C6	44.5 (6)	Cd1—N2—C2—C4	29.4 (6)
N2ⁱ—Cd1—O1—C6	−7.3 (6)	N4—C4—C2—C3ⁱⁱⁱ	−35 (8)
N2—Cd1—O1—C6	96.3 (6)	N4—C4—C2—N2	140 (7)
N3ⁱ—Cd1—O1—C6	−175.3 (6)	C1ⁱⁱ—N3—C3—C2ⁱⁱ	−0.4 (5)
N3—Cd1—O1—C6	−95.4 (6)	Cd1—N3—C3—C2ⁱⁱ	172.2 (3)
O1ⁱ—Cd1—N3—C1ⁱⁱ	−34.6 (4)	C1ⁱⁱ—N3—C3—C5	179.5 (5)
O1—Cd1—N3—C1ⁱⁱ	140.3 (4)	Cd1—N3—C3—C5	−7.9 (7)
N2ⁱ—Cd1—N3—C1ⁱⁱ	53.5 (4)	C2ⁱⁱ—C3—C5—N5	−1 (6)
N2—Cd1—N3—C1ⁱⁱ	−111.8 (7)	N3—C3—C5—N5	179 (100)
N3ⁱ—Cd1—N3—C1ⁱⁱ	−130.4 (5)	Cd1—O1—C6—N6	164.9 (6)
O1ⁱ—Cd1—N3—C3	155.1 (4)	C8—N6—C6—O1	178.2 (9)
O1—Cd1—N3—C3	−30.0 (4)	C7—N6—C6—O1	−0.2 (13)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1^iv	0.86	2.45	3.187 (6)	144
C7—H7C···N5^iv	0.96	2.68	3.429 (12)	135
C7—H7B···N4^v	0.96	2.65	3.496 (11)	148

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

Acknowledgements

This work was supported by the Nation Natural Science Foundation of China (grant Nos. 21173122 and 21006054).

References

Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2008). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Collins, D. J. & Zhou, H.-C. (2007). J. Mater. Chem. 17, 3154–3160. Web of Science CrossRef CAS Google Scholar
Desiraju, G. R. (1996). Acc. Chem. Res. 29, 441–449. CrossRef CAS PubMed Web of Science Google Scholar
Eddaoudi, M., Sava, D. F., Eubank, J. F., Adil, K. & Guillerm, V. (2015). Chem. Soc. Rev. 44, 228–249. Web of Science CrossRef CAS PubMed Google Scholar
Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662–671. Web of Science CSD CrossRef CAS Google Scholar
Gu, Z.-Y., Yang, C.-X., Chang, N. & Yan, X.-P. (2012). Acc. Chem. Res. 45, 734–745. Web of Science CrossRef CAS PubMed Google Scholar
Hu, T.-P., Liu, J.-F., Lu, X.-Y., Xiao, L.-Q. & Song, J.-F. (2013). Chin. J. Inorg. Chem. 29, 1928–1934. CAS Google Scholar
Kim, D.-W., Shin, J. W., Kim, J. H. & Moon, D. (2015). Acta Cryst. E71, 173–175. CSD CrossRef IUCr Journals Google Scholar
Li, J.-X., Du, Z.-X., Zhou, J., An, H.-Q., Zhu, B.-L., Wang, S.-R., Zhang, S.-M., Wu, S.-H. & Huang, W.-P. (2010). Inorg. Chem. Commun. 13, 127–130. Web of Science CSD CrossRef CAS Google Scholar
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Mondal, S. S., Bhunia, A., Baburin, I. A., Jäger, C., Kelling, A., Schilde, U., Seifert, G., Janiak, C. & Holdt, H. J. (2013). Chem. Commun. 49, 7599–7601. Web of Science CSD CrossRef CAS Google Scholar
Mondal, S. S., Bhunia, A., Kelling, A., Schilde, U., Janiak, C. & Holdt, H.-J. (2014). J. Am. Chem. Soc. 136, 44–47. Web of Science CSD CrossRef CAS PubMed Google Scholar
Orcajo, G., Calleja, G., Botas, J. A., Wojtas, L., Alkordi, M. H. & Sánchez-Sánchez, M. (2014). Cryst. Growth Des. 14, 739–746. Web of Science CSD CrossRef CAS Google Scholar
Prasad, B. L. V., Sato, H., Enoki, T., Cohen, S. & Radhakrishnan, T. P. (1999). J. Chem. Soc. Dalton Trans. pp. 25–30. Web of Science CSD CrossRef Google Scholar
Sava, D. F., Kravtsov, V. C., Eckert, J., Eubank, J. F., Nouar, F. & Eddaoudi, M. (2009). J. Am. Chem. Soc. 131, 10394–10396. Web of Science CSD CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Steed, J. W. & Atwood, J. L. (2000). Supramolecular Chemistry, p. 26. Chichester: John Wiley & Son. Google Scholar
Wang, S., Zhao, T.-T., Li, G.-H., Wojtas, L., Huo, Q.-S., Eddaoudi, M. & Liu, Y.-L. (2010). J. Am. Chem. Soc. 132, 18038–18041. Web of Science CSD CrossRef CAS PubMed Google Scholar
Xiong, R. G., Xue, X., Zhao, H., You, X. Z., Abrahams, B. F. & Xue, Z.-L. (2002). Angew. Chem. Int. Ed. 41, 3800–3803. CrossRef CAS Google Scholar
Yang, H., Sang, R.-L., Xu, X. & Xu, L. (2013). Chem. Commun. 49, 2909–2911. Web of Science CSD CrossRef CAS 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.