Tetra­aqua­bis(4,4′-bipyridine)zinc(II) bis­(trans-4-hydroxy­cinnamate)

Ling Chen

doi:10.1107/S1600536809023204

. 2009 Jun 20;65(Pt 7):m807. doi: 10.1107/S1600536809023204

Tetraaquabis(4,4′-bipyridine)zinc(II) bis(trans-4-hydroxycinnamate)

Ling Chen ^a,^*

PMCID: PMC2969468 PMID: 21582731

Abstract

The title complex, [Zn(C₁₀H₈N₂)₂(H₂O)₄](C₉H₇O₃)₂, was obtained by the hydrothermal reaction of zinc sulfate with mixed 4-hydroxylcinnamic acid (H₂ L) and 4,4′-bipyridine (4,4′-bipy) ligands. The complex consists of a centrosymmetric [Zn(4,4′-bipy)₂(H₂O)₄]²⁺ cation with the metal centre in a distorted ZnN₂O₄ coordination, and of two HL ⁻ anions. Extensive O—H⋯O and O—H⋯N hydrogen-bonding interactions between the constituents lead to the formation of a three-dimensional network.

Related literature

The main strategy used in the design and synthesis of novel coordination architectures is the building-block approach, see: Han et al. (2005 ▶); Wen et al. (2005 ▶); Yaghi et al. (1998 ▶). For the isostructural nickel analog, see: Zhou et al. (2006 ▶).

Experimental

Crystal data

[Zn(C₁₀H₈N₂)₂(H₂O)₄](C₉H₇O₃)₂
M _r = 776.09
Triclinic,
a = 7.0884 (4) Å
b = 7.3966 (4) Å
c = 17.2518 (10) Å
α = 86.972 (3)°
β = 83.872 (3)°
γ = 81.937 (3)°
V = 889.80 (9) Å³
Z = 1
Mo Kα radiation
μ = 0.76 mm⁻¹
T = 296 K
0.38 × 0.19 × 0.10 mm

Data collection

Bruker APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.84, T _max = 0.93
12766 measured reflections
4058 independent reflections
3831 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.080
S = 1.03
4058 reflections
256 parameters
7 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; 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/S1600536809023204/at2810sup1.cif

e-65-0m807-sup1.cif^{(20.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809023204/at2810Isup2.hkl

e-65-0m807-Isup2.hkl^{(198.9KB, 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
O1W—H1WA⋯O3	0.818 (15)	1.948 (16)	2.7549 (15)	169 (2)
O1W—H1WB⋯O3ⁱ	0.835 (14)	1.875 (15)	2.7069 (14)	174 (2)
O1—H1⋯N1ⁱⁱ	0.824 (17)	1.97 (2)	2.714 (2)	150 (3)
O2W—H2WA⋯O2ⁱⁱⁱ	0.834 (14)	1.869 (15)	2.6833 (14)	165.0 (19)
O2W—H2WB⋯O2^iv	0.823 (14)	1.919 (15)	2.7307 (15)	168.3 (19)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

supplementary crystallographic information

Comment

The main strategy widely used in design and synthesis of novel coordination architectures is the building-block approach (Yaghi et al., 1998; Han et al., 2005; Wen et al., 2005). 4-Hydroxylcinnamic acid (H₂L) is considered as suitable multidentate ligand is based on the following considerations: (a) It has multiple coordination sites, carboxylate group and phenolic hydroxyl group, that may generate structures of higher dimensions. (b) Hydroxyl group can also introduce hydrogen bond in the framework construction. Here, we combined H₂L and auxiliary ligand 4,4-bipy as a mixed ligand system to react metal ions. A new Zn(II) complex, [Zn(4,4'-bipy)₂(H₂O)₄].2HL, (I), was obtained unexpected. In this complex, HL ligand is non-coordinated and acts as a dissociative anion.

The X-ray diffraction study shows that the asymmetric unit of (I) is composed of half a Zn atom, one 4,4'-bipy ligand, two coordinated water molecules and one HL ligand. As shown in Fig.1, the Zn^II center is six-coordinated by four water molecules and two N atoms of 4,4'-bipy, and displays a slightly distorted [ZnO₄N₂] octahedral coordination geometry. Four water molecules form a relatively normal equatorial plane of the octahedron, and the Zn1 atom is located in this plane, while two N atoms occupy the axial positions, with an N—Zn—N angle of 180 °. The bond lengths of Zn—O_water are 2.0878 (10) and 2.0881 (10) Å, Zn—N is 2.1728 (12) Å, respectively.

There are extensive hydrogen-bonding interactions involving the HL oxygen atoms, coordinated water molecules and uncoordinated 4,4'-bipy N atoms. A three-dimensional network is formed by these hydrogen-bonding interactions, as shown in Fig. 2. Complex (I) is isostructural with its nickel analog (Zhou et al., 2006).

Experimental

A mixture of 4-hydroxylcinnamic acid (0.1642 g, 1 mmol), ZnSO₄.7H₂O (0.1438 g, 0.5 mmol), Na₂CO₃(0.053 g, 0.5 mmol) and H₂O (15 mL) was sealed in a 25 ml stainless-steel reactor with a Telflon liner and was heated at 433 K for 3 d. On completion of the reaction, the reactor was cooled slowly to room temperature and the mixture was filtered, giving colourless single crystals suitable for X-ray analysis in yield 30% (based on Zn).