Poly[[(methanol)(μ4-2,4,5,6-tetra­fluoro­benzene-1,3-dicarboxyl­ato)copper(II)] methanol monosolvate]

Dan Yan; Qian Duan

doi:10.1107/S1600536812020740

. 2012 May 16;68(Pt 6):m768–m769. doi: 10.1107/S1600536812020740

Poly[[(methanol)(μ₄-2,4,5,6-tetrafluorobenzene-1,3-dicarboxylato)copper(II)] methanol monosolvate]

Dan Yan ^a, Qian Duan ^a,^*

PMCID: PMC3379103 PMID: 22719324

Abstract

In the title compound, {[Cu(C₈F₄O₄)(CH₃OH)]·CH₃OH}_n, two Cu^II atoms are bridged by four carboxylate groups, forming the well known paddle-wheel secondary building unit (SBU) with axial methanol ligands. In each ligand, the dihedral angles between the benzene ring and the two carboxylate groups are 80.43 (17) and 62.5 (4)°. Within each SBU, the four carboxylate groups come from four symmetry-equivalent tetrafluoroisophthalate ligands. Each tetrafluoroisophthalate group connects two SBUs, forming a layered structure . In the crystal, O—H⋯O hydrogen bonds involving the free and ligated methanol molecules link the molecules into a three-dimensional supramolecular network.

Related literature

For background to coordination polymers, see: Kim et al. (2001 ▶); Kitagawa et al. (2004 ▶). For applications of coordination polymers, see: Wang et al. (2009 ▶); Dincă & Long (2008 ▶); Furukawa et al. (2008 ▶). For information on fluorinated coordination polymers, see: Yang et al. (2007 ▶); Hulvey et al. (2009 ▶).

Experimental

Crystal data

[Cu(C₈F₄O₄)(CH₄O)]·CH₄O
M _r = 363.70
Monoclinic,
a = 8.6542 (7) Å
b = 12.1882 (10) Å
c = 12.4272 (10) Å
β = 98.390 (1)°
V = 1296.78 (18) Å³
Z = 4
Mo Kα radiation
μ = 1.76 mm⁻¹
T = 200 K
0.34 × 0.22 × 0.19 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ▶) T _min = 0.621, T _max = 0.715
8122 measured reflections
2575 independent reflections
2365 reflections with I > 2σ(I)
R _int = 0.017

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.092
S = 1.07
2575 reflections
196 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.05 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812020740/pk2400sup1.cif

e-68-0m768-sup1.cif^{(16.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812020740/pk2400Isup2.hkl

e-68-0m768-Isup2.hkl^{(126.5KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Cu1—O2ⁱ	1.9600 (18)
Cu1—O1	1.9650 (18)
Cu1—O3ⁱⁱ	1.9656 (18)
Cu1—O4ⁱⁱⁱ	1.9734 (17)
Cu1—O5	2.0834 (19)

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5⋯O6^iv	0.84 (1)	1.80 (1)	2.637 (3)	173 (4)
O6—H6⋯O4^v	0.82	2.02	2.828 (3)	169

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Symmetry codes: (iv) Inline graphic ; (v) .

supplementary crystallographic information

Comment

The design and synthesis of coordination polymers is an active area of research as these compounds have potential uses in gas storage, catalysis, magnetism and so on. The Omary and Cheetham groups have both reported interesting hydrogen adsorption properties in porous coordination polymers containing fluorinated ligands (Yang et al. 2007; Hulvey et al. 2009). Indeed, most of the reports to date of coordination polymers containing perfluorinated dicarboxylates involve a second ligand, which is typically a simple, nonfluorinated, nitrogen-containing molecule. The well known paddlewheel secondary building unit (M₂(O₂CR)₄L₂, M=Cu, Zn, etc.; L=terminal ligand) has been used extensively in generating porous coordination polymers. Here, we report a perfluorinated coordination polymer (I), {[Cu(C₈F₄O₄)(CH₃OH)].CH₃OH}_n, which is constructed using the paddlewheel SBU Cu₂(O₂CR)₄L₂ (L=CH₃OH).

The asymmetric unit is composed of one Cu^II center, one tetrafluoroisophthalate anion, one coordinated methanol ligand, and one methanol solvent molecule (Fig. 1). Each Cu^II ion is five-coordinated by four oxygen donors from four different tetrafluoroisophthalate ligands and one oxygen atom from a terminal methanol molecule. In the paddlewheel SBU, the two copper ions are separated by 2.6622 (6) Å. Each SBU connects four tetrafluoroisophthalate ligands, and each tetrafluoroisophthalate group connect two SBUs to form a two dimensional layered structure (Fig. 2). Adjacent parallel layers are connected by O—H···O hydrogen bonds between guest methanol molecules and the coordinated methanol molecules to create a three-dimensional supramolecular network.

Experimental

Compound I was obtained by layering 5 ml of a methanol solution containing 2,4,5,6-tetrafluoro-1,3-benzenedicarboxylic acid (23 mg, 0.10 mmol) and 2,6-lutidine (0.034 ml, 0.30 mmol) onto 5 ml of a methanol/nitrobenzene solution (1.5:1, v/v) containing Cu(NO₃)₂.2.5H₂O (23 mg, 0.10 mmol). Green crystals formed at the interlayer boundary within one week. After two weeks, blue block-shaped crystals of the title compound suitable for X-ray diffraction were obtained by slow diffusion of the solvents in 26% yield (9.5 mg, based on the ligand).