Aqua­(4-nitro­phthalato)bis­[2-(1H-pyrazol-3-yl)pyridine]­zinc(II) hemihydrate

Lei Ni; Ji-Li Zhao; Hong Wei

doi:10.1107/S1600536810051949

. 2010 Dec 24;67(Pt 1):m105. doi: 10.1107/S1600536810051949

Aqua(4-nitrophthalato)bis[2-(1H-pyrazol-3-yl)pyridine]zinc(II) hemihydrate

Lei Ni ^a,^*, Ji-Li Zhao ^a, Hong Wei ^a

PMCID: PMC3050407 PMID: 21522519

Abstract

In the title compound, [Zn(C₈H₃NO₆)(C₈H₇N₃)₂(H₂O)]·0.5H₂O, the Zn^II atom shows a distorted octahedral ZnN₄O₂ coordination environment and is bonded to two 3-(2-pyridyl)-1H-pyrazole ligands via the N atoms, one monodentate 4-nitrophthalate ligand and one associated water molecule. Additionally, one water of crystallization, with a site-occupation factor of 0.5, is present. The two 3-(2-pyridyl)-1H-pyrazole ligands are planar [r.m.s. deviations = 0.03 (1) and 0.35 (1) Å] and the dihedral angle between the two planar 3-(2-pyridyl)-1H-pyrazole ligands is 67.31 (4)°. Intermolecular π–π stacking interactions between 3-(2-pyridyl)-1H-pyrazole ligands with a face-to-face separation of 3.64 (1) Å are observed. Moreover, the crystal structure is stabilized by O—H⋯O and N—H⋯O hydrogen bonds between the water of crystallization, the associated water molecule and the 3-(2-pyridyl)-1H-pyrazole ligands.

Related literature

For background to metal-organic frameworks, see: Hagrman et al. (1999 ▶); Kitagawa et al. (2004 ▶).

Experimental

Crystal data

[Zn(C₈H₃NO₆)(C₈H₇N₃)₂(H₂O)]·0.5H₂O
M _r = 591.84
Triclinic,
a = 10.4284 (6) Å
b = 11.1844 (7) Å
c = 11.9656 (8) Å
α = 96.508 (3)°
β = 112.091 (3)°
γ = 96.366 (3)°
V = 1266.84 (14) Å³
Z = 2
Mo Kα radiation
μ = 1.03 mm⁻¹
T = 294 K
0.12 × 0.10 × 0.08 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.886, T _max = 0.922
9062 measured reflections
4258 independent reflections
3825 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.104
S = 1.00
4258 reflections
364 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.65 e Å⁻³
Δρ_min = −0.42 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-Plus (Bruker, 2001 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810051949/im2226sup1.cif

e-67-0m105-sup1.cif^{(21.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810051949/im2226Isup2.hkl

e-67-0m105-Isup2.hkl^{(208.6KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H2W⋯O5ⁱ	0.82 (3)	1.81 (3)	2.627 (3)	174 (3)
N5—H5A⋯O4ⁱ	0.86	1.95	2.788 (3)	166
N2—H2A⋯O2	0.86	1.82	2.606 (4)	150

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge financial support from the Science Foundation of Beihua University.

supplementary crystallographic information

Comment

The synthesis of entangled metal-organic frameworks (MOFs) has attracted continuous research interest not only because of their appealing structural and topological novelty, but also due to their unusual optical, electronic, magnetic, and catalytic properties, as well as their potential medical application (Hagrman et al. (1999); Kitagawa et al. (2004)). Here, we describe the synthesis and structural characterization of the title compound resulting from an attempted MOF synthesis in which Zn and Gd complex building blocks were expected to be the constituents.

Single crystal X-ray diffraction analyses revealed that the asymmetric unit of the title compound, [(Zn(C₈H₇N₃)₂(C₈NH₃O₆)(H₂O)].(H₂O)_0.5, consists of one Zn²⁺ ion, two 3-(2-pyridyl)-1H-pyrazole ligands, one 4-Nitrophthalato ligand, one associated water molecule, and half water of crystallization. As shown in Figure 1, the Zn²⁺ ion is hexacoordinated by four N atoms from 3-(2-pyridyl)-1H-pyrazole ligands and two oxygen atoms from 4-Nitrophthalato ligand and one associated water molecule, exhibiting a distorted octahedral arrangement of ZnN₄O₂. Moreover, the Rms deviations of the two 3-(2-pyridyl)-1H-pyrazole groups from planarity are 0.03 (1) and 0.35 (1) Å, respectively. The dihedral angle between the two 3-(2-pyridyl)-1H-pyrazole planars is 67.31 (4) Å. Interestingly, between the molecules, there is π-π stacking interactions with the face-to-face separation (ca 3.64 (1) Å) between the 3-(2-pyridyl)-1H-pyrazole planars. Meantime, there are extensive hydrogen bonds between water of crystallization, associated water molecule, and 3-(2-pyridyl)-1H-pyrazole, and leads to a consolidation of the structure (Figure 2).

Experimental

A mixture of zinc oxalate dihydrate (0.26 mmol, 0.050 g), 3-(2-pyridyl)-1H-pyrazole (0.32 mmoL, 0.05 g), 4-nitrophthalic acid (0.24 mmoL, 0.05 g), gadolinium(III) nitrate pentahydrate (0.12 mmoL, 0.05 g), and 14 ml H₂O was sealed in a 25 ml Teflon-lined stainless steel autoclave at 433 K for three days. Pink crystals suitable for the X-ray experiment were obtained. The yield is 60% based on the zinc salt. Anal. Calc. for C₄₈H₄₀N₁₄O₁₅Zn₂: C 48.65, H 3.38, N 16.55%; Found: C 48.32, H 3.15, N 16.39%.