catena-Poly[[diaqua­bis­(formato-κO)cobalt(II)]-μ2-2,6-bis­(pyridin-4-yl)-4,4′-bipyridine-κ2 N 2:N 6]

De-Yun Ma; De-En Sun; Guo-Qing Li

doi:10.1107/S1600536811021118

. 2011 Jun 11;67(Pt 7):m913. doi: 10.1107/S1600536811021118

catena-Poly[[diaquabis(formato-κO)cobalt(II)]-μ₂-2,6-bis(pyridin-4-yl)-4,4′-bipyridine-κ² N ²:N ⁶]

De-Yun Ma ^a, De-En Sun ^a, Guo-Qing Li ^a,^*

PMCID: PMC3151864 PMID: 21836898

Abstract

In the title complex, [Co(CHO₂)₂(C₂₀H₁₄N₄)(H₂O)₂]_n, the Co^II ion, lying on an inversion center, is six-coordinated by two O atoms from two monodentate formate ligands, two N atoms from two 2,6-bis(pyridin-4-yl)-4,4′-bipyridine (4-pybpy) ligands and two water molecules, displaying an octahedral geometry. The 4-pybpy ligand, having a twofold rotation axis, functions in a bridging coordination mode, connecting the Co^II ions into a corrugated chain along [ Inline graphic 01]. The chains are further linked into a three-dimensional supramolecular network by O—H⋯O, C—H⋯N and C—H⋯O hydrogen bonds and π–π stacking interactions between the pyridine rings [centroid-to-centroid distance = 3.743 (2) Å].

Related literature

For general background to complexes with 2,6-bis(4-pyridyl)-4,4′-bipyridine, see: Liu et al. (2009 ▶); Yoshida et al. (2007 ▶).

Experimental

Crystal data

[Co(CHO₂)₂(C₂₀H₁₄N₄)(H₂O)₂]
M _r = 495.35
Monoclinic,
a = 24.412 (5) Å
b = 11.073 (2) Å
c = 7.4117 (15) Å
β = 91.28 (3)°
V = 2003.0 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.91 mm⁻¹
T = 293 K
0.30 × 0.26 × 0.21 mm

Data collection

Rigaku/MSC Mercury CCD diffractometer
Absorption correction: multi-scan (CrystalStructure; Rigaku/MSC, 2002 ▶) T _min = 0.075, T _max = 0.126
9417 measured reflections
2303 independent reflections
1544 reflections with I > 2σ(I)
R _int = 0.063

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.112
S = 1.11
2303 reflections
160 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.76 e Å⁻³
Δρ_min = −0.57 e Å⁻³

Data collection: CrystalStructure (Rigaku/MSC, 2002 ▶); cell refinement: CrystalStructure; data reduction: CrystalStructure; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811021118/hy2424sup1.cif

e-67-0m913-sup1.cif^{(20.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811021118/hy2424Isup2.hkl

e-67-0m913-Isup2.hkl^{(113.3KB, 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—H1W⋯O2ⁱ	0.82 (1)	1.97 (1)	2.775 (3)	166 (4)
O1W—H2W⋯O2ⁱⁱ	0.82 (1)	1.99 (1)	2.814 (3)	174 (3)
C2—H2⋯N3ⁱⁱⁱ	0.93	2.62	3.458 (3)	150
C5—H5⋯O2ⁱⁱ	0.93	2.53	3.429 (4)	164

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

Acknowledgments

The authors acknowledge South China University of Technology for supporting this work.

supplementary crystallographic information

Comment

In the structural investigation of 2,6-bis(4-pyridyl)-4,4'-bipyridine (4-pybpy) complexes, it has been found that 4-pybpy functions as a multidentate ligand (Liu et al., 2009; Yoshida et al., 2007), with versatile binding and coordination modes. In this paper, we report the crystal structure of the title compound, a new Co^II complex obtained by the reaction of 4-pybpy, cobaltous nitrate hexahydrate in DMF solution.

As depicted in Fig. 1, the Co^II atom, lying on an inversion center, is coordinated by two O atoms from two formate anions, two N atoms from two 4-pybpy ligands and two water molecules. The coordination environment of the Co^II atom can be described as octahedral. The 4-pybpy ligands link Co^II ions, forming infinite chains, with a Co···Co separation of 12.835 (2) Å (Fig. 2). These chains are further self-assembled into a three-dimensional supramolecular network via intermolecular O—H···O and C—H···O hydrogen bonds (Table 1) involving the water molecules as donors and O atoms of the formate groups as acceptors, and π–π stacking interactions between the pyridyl rings of neighboring 4-pybpy ligands (Fig. 3). The centroid–centroid distance is 3.743 (2) Å.

Experimental

A mixture of 4-pybpy (0.155 g, 0.5 mmol), cobalt nitrate hexahydrate (0.145 g, 0.5 mmol) and DMF (15 ml) was placed in a 23 ml Teflon-lined reactor, which was heated at 358 K for 2 d, and then cooled to room temperature at a rate of 10 K h^-1. Block purple crystals obtained were washed with water and dried in air (yield: 45% based on Co).