Poly[μ6-pyridine-2,4-dicarboxyl­ato-barium]

Qi Shuai; Xiao-Nong Zhao; Li Zhao; Fan Hu

doi:10.1107/S1600536810023457

. 2010 Jun 23;66(Pt 7):m832. doi: 10.1107/S1600536810023457

Poly[μ₆-pyridine-2,4-dicarboxylato-barium]

Qi Shuai ^a,^*, Xiao-Nong Zhao ^a, Li Zhao ^b, Fan Hu ^c

PMCID: PMC3006690 PMID: 21587745

Abstract

In the title complex, [Ba(C₇H₃NO₄)]_n, the coordination geometry around the Ba^II ion can be described as a distorted bicapped trigonal-prismatic BaNO₇ arrangement. The pyridine-2,4-dicarboxylic acid ligands exhibit a new coordination mode. Adjacent metal centers are linked by the O atoms of the pyridine-2,4-dicarboxylic acid ligands, and then form a three-dimensional supramolecular polymeric framework.

Related literature

For related structures, see: Frisch & Cahill (2006 ▶); Huang et al. (2007 ▶); Li et al. (2008 ▶); Liang et al. (2002 ▶); Noro et al. (2002 ▶); Soleimannejad et al. (2009 ▶); Zhang (2005 ▶).

Experimental

Crystal data

[Ba(C₇H₃NO₄)]
M _r = 302.44
Monoclinic,
a = 11.7570 (11) Å
b = 7.2121 (7) Å
c = 17.4547 (16) Å
β = 93.471 (1)°
V = 1477.3 (2) Å³
Z = 8
Mo Kα radiation
μ = 5.35 mm⁻¹
T = 296 K
0.37 × 0.34 × 0.07 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2002 ▶) T _min = 0.325, T _max = 0.783
4192 measured reflections
1662 independent reflections
1547 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.018
wR(F ²) = 0.048
S = 1.03
1662 reflections
119 parameters
H-atom parameters constrained
Δρ_max = 0.70 e Å⁻³
Δρ_min = −0.45 e Å⁻³

Data collection: SMART (Bruker, 2002 ▶); cell refinement: SAINT (Bruker, 2002 ▶); 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 global, I. DOI: 10.1107/S1600536810023457/pb2031sup1.cif

e-66-0m832-sup1.cif^{(16.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810023457/pb2031Isup2.hkl

e-66-0m832-Isup2.hkl^{(82KB, hkl)}

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

Acknowledgments

This work was supported by the Scientific Research Foundation of Northwest A&F University (grant No. Z111020828).

supplementary crystallographic information

Comment

Complex of Sr^II ion with pyridine-2,4-dicarboxylic acid, [Sr(C₇H₃NO₄)(H₂O)₂]_n, has been previously studied (Soleimannejad et al., 2009), which is a two-dimensional polymer.

Here we report a complex (I) assembled by alkaline earth metal Ba^II ion with pyridine-2,4-dicarboxylic acid ligand. The formula for the complex is [Ba(C₇H₃NO₄)]_n, X-ray crystal analyse reveals that the pyridine-2,4-dicarboxylic acid ligands in the complex are completely deprotonated, which is the same with the complex of [Sr(C₇H₃NO₄)(H₂O)₂]_n.

In the title complex, the asymmetric unit consists of one Ba^II ion and one pyridine-2,4-dicarboxylate. The coordination geometry around Ba^II ion (Fig. 1) could be described as a distorted bicapped trigonal prism arrangement with coordination number of 8, where N1, O2B and O4D form the top plane of the trigonal prism, and the bottom plane is completed by O3A, O4E, and O1C, while O1 and O3E capped two quadrilateral faces formed by N1, O3A, O1C, O4D and O2B, O4E, O1C, O4D, respectively. All the coordinated atoms in the title complex are oxygen atoms and nitrogen atoms of pyridine-2,4-dicarboxylic acid ligands, which is different from the complex of [Sr(C₇H₃NO₄)(H₂O)₂]_n, oxygen atoms of water molecules also take part in the coordination with metal centers. The bond length of Ba—O_carboxylate bonds range from 2.706 (2) to 2.8941 (19) Å, which compare well with the mean value determined from the CSD [2.798 (7) Å for Ba—O_carboxylate bond](Table 1). The coordination mode (Fig. 2) of pyridine-2,4-dicarboxylic acid ligands can be classified as µ₆-(κ⁸N, O¹: O¹: O²: O³: O³: O⁴: O⁴), that is, two 4-position carboxylate oxygen atoms (O3 and O4) coordinate to three Ba^II ions, one of the 2-position carboxylate oxygen atoms (O1) coordinates to two Ba^II ions, at the same time, this oxygen atom chelate a Ba^II ion with the pyridyl nitrogen (N1). The other 2-position oxygen atom (O2) coordinates to one Ba^II ion. This coordination mode is not observed in previous reports (Soleimannejad et al., 2009; Huang et al., 2007; Zhang, 2005; Liang et al., 2002; Li et al., 2008; Frisch et al., 2006; Noro et al., 2002). The adjacent metal centers are linked by the oxygen and nitrogen atoms of pyridine-2,4-dicarboxylic acid ligands, and then form a three-dimensional supramolecular polymeric framework (Fig. 3), while in the complex of Sr(C₇H₃NO₄)(H₂O)₂]_n (Soleimannejad et al., 2009), the three-dimensional structure is constructed by non-covalent interactions consisting of O—H···O hydrogen bonds and π-π stacking interactions.

Experimental

A mixture of barium chloride dihydrate (0.0244 g, 0.1 mmol), sodium hydroxide (0.0080 g, 0.2 mmol), pyridine-2,4-dicarboxylic acid (0.0167 g, 0.1 mmol), and H₂O (3 mL) was placed in a Parr Teflon-lined stainless stell vessel (25 ml), and then the vessel was sealed and heated at 443.15 K for 4 days. Then the vessel was cooled to 373.15 K at a rate of 5 K h^-1 and slowly cooled to room temperature. Colorless, rectangular single crystals suitable for X-ray diffraction were obtained.