catena-Poly[[[aqua­tripyridine­cobalt(II)]-μ-5-amino-2,4,6-triiodoisophthalato-κ2 O 1:O 3] pyridine solvate]

Yu Zhang; Jianying Zhao; Guodong Tang; Zhengjing Jiang

doi:10.1107/S1600536808032017

. 2008 Oct 15;64(Pt 11):m1392–m1393. doi: 10.1107/S1600536808032017

catena-Poly[[[aquatripyridinecobalt(II)]-μ-5-amino-2,4,6-triiodoisophthalato-κ² O ¹:O ³] pyridine solvate]

Yu Zhang ^a,^*, Jianying Zhao ^a, Guodong Tang ^a, Zhengjing Jiang ^a

PMCID: PMC2959533 PMID: 21580844

Abstract

The reaction of cobalt(II) nitrate with 5-amino-2,4,6-triiodoisophthalic acid (ATPA) in pyridine solution leads to the formation of the title compound, {[Co(C₈H₂I₃NO₄)(C₅H₅N)₃(H₂O)]·C₅H₅N}_n. The Co²⁺ ion is six-coordinated by three N atoms, one water O atom and two O atoms from two ATPA ligands to form a distorted octahedral geometry. The two carboxylate groups of ATPA act as bridging ligands connecting the Co^II metal centers to form one-dimensional zigzag chains along the c axis, with Co—O distances in the range 2.104 (4)–2.135 (4) Å. The average Co—N distance is 2.171 Å. A classical O—H⋯N hydrogen bond is formed by the coordinating water molecule and the pyridine solvent molecule. The structure was refined from a racemically twinned crystal with a twin ratio of approximately 8:1.

Related literature

For the structure of a monohydrate of ATPA, see: Beck & Sheldrick (2008 ▶). For the Co coordination polymer of 1,3,5-benzenetricarboxylate, see: Livage et al. (2001 ▶). For the structure of diaquadiformatodipyridine Co^II, see: Zhu et al. (2004 ▶). For a reduction of the organic iodine contrast agents in wastewater load, see: Ziegler et al. (1997 ▶).

Experimental

Crystal data

[Co(C₈H₂I₃NO₄)(C₅H₅N)₃(H₂O)]·C₅H₅N
M _r = 950.15
Orthorhombic,
a = 9.7759 (2) Å
b = 16.9083 (4) Å
c = 19.3380 (4) Å
V = 3196.45 (12) Å³
Z = 4
Mo Kα radiation
μ = 3.48 mm⁻¹
T = 296 (2) K
0.30 × 0.25 × 0.08 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ▶) T _min = 0.38, T _max = 0.75
16692 measured reflections
6038 independent reflections
4577 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.065
S = 1.04
6038 reflections
379 parameters
3 restraints
H-atom parameters constrained
Δρ_max = 0.68 e Å⁻³
Δρ_min = −0.67 e Å⁻³
Absolute structure: Flack (1983 ▶), with 2515 Friedel pairs
Flack parameter: 0.13 (2)

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808032017/si2113sup1.cif

e-64-m1392-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808032017/si2113Isup2.hkl

e-64-m1392-Isup2.hkl^{(295.6KB, hkl)}

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

Table 1. Selected geometric parameters (Å, °).

Co1—O1ⁱ	2.104 (4)
Co1—O5	2.106 (3)
Co1—O3	2.135 (4)
Co1—N2	2.161 (5)
Co1—N3	2.173 (5)
Co1—N4	2.180 (5)

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O1ⁱ—Co1—O3	170.52 (16)
O1ⁱ—Co1—N3	102.93 (17)
O5—Co1—N3	172.68 (17)
N2—Co1—N4	178.48 (19)

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Symmetry code: (i) Inline graphic .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5A⋯N5ⁱⁱ	0.85	1.94	2.748 (7)	159

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Symmetry code: (ii) Inline graphic .

Acknowledgments

This work was financially supported by the Natural Science Foundation of Jiangsu Province Education Office (grant No. 04KJB150015). We also thank Dr Zaichao Zhang for his support.

supplementary crystallographic information

Comment

The crystal structure of ATPA (Beck & Sheldrick, 2008) is the precursor of the synthesis of a wide range of contrast agents with different amide-bound aliphatic side chains, which modulate their physical and physiological properties (Ziegler et al. 1997). However, to the best of our knowledge, there is no information about the structural characterization of its transition metal complexes.

The molecular structure of the title complex comprises of polymeric chains which extend along the c-axis. In the chain, each Co atom shows a distorted octahedron environment with a [3N+3O] coordination: three nitrogen atoms originate from pyridines, one oxygen from a water molecule and two oxygen atoms from two ATPA ligands. The two CO₂^- groups of the ATPA ligand coordinate to Co²⁺, bridging the Co metal centers. The bond lengths of the distorted octahedron are presented in Table 1. The average Co—N bond distance of the three pyridine ligands is 2.171 Å. The Co—O bond lengths in the title complex are slightly longer than those in the reported coordination polymers of cobalt and 1,3,5-benzenetricarboxylate (2.055 (2) Å) (Livage et al., 2001). The bond angles shown in Table 1 demonstrate the distorted octahedron in the Co coordination center. Compared with the data of the free ligand ATPA (Beck & Sheldrick, 2008), the C—O bond lengths are lengthened, the C—I and C—N bond distances are almost unchanged and the O—C—O bond angles are slightly expanded when the carboxylate groups are coordinated to central cations. The Co—N(py) and Co—O(H₂O) distances are in good agreement with those in diaqua-diformato-dipyridine-cobalt(II) (Zhu et al., 2004), where they are equal to 2.159 (4) Å and 2.143 (3) Å, respectively. A classic O—H···N hydrogen bond is formed by the coordinating water and the uncoordinated pyridine molecule (Table 2).

Experimental

0.29 g (1 mmol) Co(NO₃)₂.6H₂O was dissolved in 10 ml ethanol, 0.54 g (1 mmol) 5-amino-2, 4, 6-triiodoisophthalic acid was dissolved in 10 ml pyridine. To mix two solutions gave a pale purple solution which was stirred at room temperature for 2 h, then filtered. After several days well formed light purple single crystals were obtained.