Poly[bis­(N,N-dimethyl­formamide-κO)(μ4-naphthalene-1,5-disulfonato)magnesium(II)]

Lauren A Borkowski; Debasis Banerjee; John B Parise

doi:10.1107/S1600536810017952

. 2010 May 22;66(Pt 6):m691–m692. doi: 10.1107/S1600536810017952

Poly[bis(N,N-dimethylformamide-κO)(μ₄-naphthalene-1,5-disulfonato)magnesium(II)]

Lauren A Borkowski ^a,^*, Debasis Banerjee ^b, John B Parise ^c

PMCID: PMC2979591 PMID: 21579330

Abstract

The structure of the title compound, [Mg(C₁₀H₆O₆S₂)(C₃H₇NO)₂]_n, consists of MgO₆ octahedra ( Inline graphic symmetry) connected to naphthalene-1,5-disulfonate ligands ( symmetry) in the equatoral plane, forming a two-dimensional network propagating parallel to (010). The coordination sphere of the Mg atom is completed by the O atoms of two N,N-dimethylformamide (DMF) molecules in the axial positions. The title compound represents the first time the naphthalene-1,5-disulfonate anion is bound directly to a Mg²⁺ atom. Disorder over two positions was found in the DMF molecule in a 0.518 (8):0.482 (8) ratio.

Related literature

For background to metal-organic coordination polymers (CPs) and frameworks (MOFs), see: Cheetham et al. (2006 ▶); Kitagawa et al. (2004 ▶); Rosseinsky (2004 ▶); Rowsell & Yaghi (2004 ▶). For structures in which Mg²⁺ is not directly linked to naphthalenedisulfonate ligands but is surrounded by water molecules, see: Cody & Hazel (1977 ▶); Morris et al. (2003 ▶); Shakeri & Haussühl (1992 ▶).

Experimental

Crystal data

[Mg(C₁₀H₆O₆S₂)(C₃H₇NO)₂]
M _r = 456.79
Triclinic,
a = 5.1328 (2) Å
b = 9.3890 (4) Å
c = 10.4029 (4) Å
α = 85.158 (1)°
β = 75.638 (1)°
γ = 79.501 (1)°
V = 477.13 (3) Å³
Z = 1
Synchrotron radiation
λ = 0.41328 Å
μ = 0.08 mm⁻¹
T = 100 K
0.09 × 0.03 × 0.01 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.993, T _max = 0.999
8811 measured reflections
1961 independent reflections
1721 reflections with I > 2σ(I)
R _int = 0.054

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.087
S = 1.04
1961 reflections
221 parameters
6 restraints
Only H-atom coordinates refined
Δρ_max = 0.61 e Å⁻³
Δρ_min = −0.51 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT-Plus (Bruker, 2007 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalMaker (CrystalMaker, 2009 ▶); software used to prepare material for publication: enCIFer (Allen et al., 2004 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810017952/wm2328sup1.cif

e-66-0m691-sup1.cif^{(17.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810017952/wm2328Isup2.hkl

e-66-0m691-Isup2.hkl^{(90.9KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Mg1—O1	2.0193 (11)
Mg1—O2ⁱ	2.0429 (11)
Mg1—O4	2.1562 (11)

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported by the National Science Foundation (DMR-0800415). The authors would like to thank Yu-Sheng Chen at ChemMatCARS, APS, for his assistance during the data collection. ChemMatCARS (APS, Sector 15) is principally supported by the National Science Foundation/Department of Energy under grant No. CHE-0535644. Use of the Advance Photon Source was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE—AC02-06CH11357.

supplementary crystallographic information

Comment

Interest in metal organic coordination polymers (CPs) and frameworks (MOFs) arises due to the potential applications including size/shape catalysis and gas storage/separation (Cheetham et al., 2006; Kitagawa et al., 2004; Rosseinsky, 2004; Rowsell & Yaghi, 2004). This is owing to the fact that these materials have similar properties to zeolites with the added possiblity of structural design. Three factors need to be considered during the sythesis of CPs and MOFs; the coordination sphere of the metal center, the size, shape and functionality of the organic linker and the synthetic conditions.

Previous studies have looked at the interaction between a variety of metal atoms and 1,5-naphthalenedisulfonic acid. A search of the literature results in examples of direct bonding between this ligand and every alkali and alkali earth metal except Mg²⁺. Due to perodic trends we suspected that Mg²⁺ and naphthalene-1,5-disulfonate should have a direct bonding interaction, which indicates a change in synthetic conditions compared to the previous studies was needed. The previous efforts used water as the solvent resulting in structures where the Mg²⁺ atoms are bound solely to water molecules and interacted with 1,5-naphthalenedisulfonic acid through hydrogen bonds (Cody & Hazel, 1977; Morris et al., 2003; Shakeri & Haussühl, 1992). In our study we used N,N-dimethylformamide (DMF) as the solvent with the thought that DMF is a large solvent molecule and is unlikely to complete for the coordination sphere of the Mg²⁺ atom.

The title compound consists of MgO₆ octahedra linked by 1,5- naphthalenedisulfonate ligands to form a two-dimensional network parallel to (010). The Mg²⁺ atom is bound to four O atoms from four separate naphthalene-1,5-disulfonate ligands in the equitorial plane and two O atoms from two symmetry equivalent N,N-dimethylformamide molecules in the axial positions (Figure 1). The average equitorial Mg—O bond length is 2.031 Å whereas the axial bond length is slightly longer at 2.156 Å (Table 1). The individual MgO₆ octahedra are connected by the naphthalene-1,5-disulfonate linkers in a bridging bidentate fashion to form chains along the [100] direction, which are further connected by the linker molecules to form an overall 2-dimensional structure (Figure 2).

Experimental

All of the starting materials are available commercially and were used without any further purification. Magnesium nitrate hexahydrate (Mg(NO₃)₂^.6H₂O, 1.3 grams), 1,5-naphthalenedisulfonic acid tetrahydrate (C₁₀H₈S₂O₆ 4H₂O, 1.87 grams) and ammonium fluoride (NH₄F, 0.021 grams) were dissolved in 15 grams of N,N-dimethylformamide (DMF). The solution was prepared in a 23 mL Teflon lined Parr bomb and stirred for three hours to achieve homogeneity. The resulting solution was heated statically at 373 K for three days. Colorless needle shaped crystals were recovered and were washed with ethanol.