Bis(μ-2-hydroxy­benozato)-κ3 O,O′:O′;κ3 O:O,O′-bis­[(2-hydroxy­benozato-κ2 O,O′)(1,10-phenanthroline-κ2 N,N′)cadmium(II)]

Qing-Yuan Shi; Zhi-Cheng Li; Zong-Sheng Cheng; Jing-Bo Tan; Jia-Lun Liu

doi:10.1107/S1600536808033886

. 2008 Oct 25;64(Pt 11):m1458. doi: 10.1107/S1600536808033886

Bis(μ-2-hydroxybenozato)-κ³ O,O′:O′;κ³ O:O,O′-bis[(2-hydroxybenozato-κ² O,O′)(1,10-phenanthroline-κ² N,N′)cadmium(II)]

Qing-Yuan Shi ^a,^*, Zhi-Cheng Li ^a, Zong-Sheng Cheng ^a, Jing-Bo Tan ^a, Jia-Lun Liu ^a

PMCID: PMC2959752 PMID: 21580896

Abstract

The dinuclear title compound, [Cd₂(C₇H₅O₃)₄(C₁₂H₈N₂)₂], is located on a crystallographic rotation twofold axis. The two Cd^II ions are connected by two tridentate bridging 2-hydroxybenzoate anions. Each Cd^II ion is seven-coordinated by five O atoms from three 2-hydroxybenzoate ligands and two N atoms from 1,10-phenanthroline. The 2-hydroxybenzoate molecules adopt two kinds of coordination mode, bidentate chelating and tridentate bridging–chelating. Intramolecular hydrogen bonds between hydroxy and carboxylate groups from 2-hydroxybenzoate groups and π–π stacking interactions between parallel 1,10-phenanthroline ligands [centroid–centroid distances = 3.707 (3) and 3.842 (3) Å] are observed. Furthermore, adjacent benzene rings from 2-hydroxybenzoate ligands are involved in π–π interactions with interplanar distances of 3.642 (3) Å, thereby forming a chain along the a axis direction.

Related literature

For general background, see: Horike et al. (2007 ▶); Humphrey et al. (2007 ▶); Sudik et al. (2005 ▶); Zhang et al. (2008 ▶). For related structures, see: Du et al. (2007 ▶); Pan et al. (2006 ▶); Tomas et al. (2006 ▶). For related literature, see: Tong et al. (1999 ▶)

Experimental

Crystal data

[Cd₂(C₇H₅O₃)₄(C₁₂H₈N₂)₂]
M _r = 1133.65
Monoclinic,
a = 27.9391 (19) Å
b = 10.3078 (7) Å
c = 20.468 (2) Å
β = 130.770 (1)°
V = 4464.2 (6) Å³
Z = 4
Mo Kα radiation
μ = 1.03 mm⁻¹
T = 298 (2) K
0.30 × 0.25 × 0.18 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.748, T _max = 0.837
11963 measured reflections
4390 independent reflections
3671 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.026
wR(F ²) = 0.067
S = 1.06
4390 reflections
316 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.36 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 1999 ▶); 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 ▶) and ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808033886/zl2145sup1.cif

e-64-m1458-sup1.cif^{(26.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808033886/zl2145Isup2.hkl

e-64-m1458-Isup2.hkl^{(215.2KB, 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
O6—H6A⋯O4	0.82	1.86	2.579 (3)	146
O3—H3A⋯O2	0.82	1.87	2.576 (2)	143

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Acknowledgments

The authors gratefully acknowledge financial support from the Scientific Research Project for Comprehensive Talent Cultivation of South China Normal University (2008–2009).

supplementary crystallographic information

Comment

Transition metal complexes with substituted benzoate ligands have attracted wide attention in past decades, owing to their variable high-dimensional architectures and potential applications for gas absorption and separation, and catalysis, etc [Du et al., 2007; Horike et al., 2007; Humphrey et al., 2007; Pan et al., 2006; Sudik et al., 2005; Tomas et al., 2006; Zhang et al., 2008]. Herein, we report the synthesis and crystal structure of the title compound, obtained by the reaction of Sm(NO₃)₃, Cd(CH₃COO)₂, 1,10-phenanthroline and 2-hydroxybenzoic acid. No samarium was however incorporated in the crystals isolated and the title compound is a dinuclear Cd^II complex of 2-hydroxybenzoic acid and 1,10-phenanthroline. A perspective view of the complex, showing the atomic numbering scheme, is depicted in Fig. 1. Each Cd^II is seven-coordinated by five oxygen atoms from three 2-hydroxybenzoate ligands, and two nitrogen atoms from 1,10-phenanthroline, and the coordination geometry around the Cd^II ion may be described as a distorted mono-capped trigonal prism. Two adjacent Cd^II units are connected by two bridging 2-hydroxybenzoate anions to generate a dinuclear complex. The 2-hydroxybenzoate molecules adopt two kinds of coordination modes, bidentate chelating and tridentate bridging-chelating. The inequivalence between the mono and bidentate bridging oxygen atoms is evident from the Cd—O bond distances: the Cd—O distances of the bridging oxygen atoms are longer than those of the monodentate oxygen atoms: Cd1—O5 is 2.421 (2) Å and Cd1—O5ⁱ is 2.491 (2) Å, while Cd1—O1, Cd—O2 and Cd—O4 are 2.399 (2), 2.327 (2) and 2.363 (2) Å, respectively (symmetry code: (i): -x, y, 1/2 - z).

Intramolecular hydrogen bonds between hydroxyl and carboxylate groups from the 2-hydroxybenzoates [O6···O4 = 2.579 (3) Å and O3···O2 = 2.576 (2) Å, Table 1] and π-π stacking attractions between parallel 1,10-phenanthroline ligands [centroid to centroid distances: 3.707 (3) and 3.842 (3) Å] are clearly observed in this complex, which may contribute to its stability.

Furthermore, adjacent phenyl rings from 2-hydroxybenzoate ligands are also involved in π-π stacking interactions by partial overlap of π-electron densities (Tong et al., 1999). The centroid-centroid separation between rings A (atoms C14—C19) and B^j [atoms C21—C26; symmetry code: (j): 1/2 + x, 1/2 - y, 1/2 + z] is 3.642 (3) Å. Considering these π-π intermolecular attractions, they imply the formation of a one-dimensional chain along the direction of the a-axis. (Fig. 2).

Experimental

A sample of Sm(NO₃)₃.6H₂O (0.090 g, 0.20 mmol), Cd(CH₃COO)₂.2H₂O (0.052 g, 0.20 mmol), 2-hydroxybenzoic acid (0.070 g, 0.50 mmol), 1,10-phenanthroline (0.036 g, 0.20 mmol) and distilled water (8 ml) were mixed in a 15 ml Teflon-lined stainless steel vessel and the pH value was adjusted to about 5 with NaOH. Then, the mixture was heated to 393 K under autogenous pressure for 48 h, and cooled slowly to room temperature. Colorless block-like crystals suitable for X-ray single-crystal diffraction analysis were obtained by filtration and washed with distilled water and ethanol.