catena-Poly[[(2-methyl­benzoato-κ2 O,O′)sodium]-di-μ-aqua-κ4 O:O′]

Muhammad Danish; Iram Saleem; Nazir Ahmad; Abdul Rauf Raza; Wojciech Starosta; Janusz Leciejewicz

doi:10.1107/S1600536810010536

. 2010 Mar 27;66(Pt 4):m459–m460. doi: 10.1107/S1600536810010536

catena-Poly[[(2-methylbenzoato-κ² O,O′)sodium]-di-μ-aqua-κ⁴ O:O′]

Muhammad Danish ^a,^*, Iram Saleem ^a, Nazir Ahmad ^a, Abdul Rauf Raza ^a, Wojciech Starosta ^b, Janusz Leciejewicz ^b

PMCID: PMC2984086 PMID: 21580545

Abstract

In the title coordination polymer, [Na(C₈H₇O₂)(H₂O)₂]_n, the cation is chelated by the carboxylate O atoms of the anion in a bidentate mode and is surrounded by the O atoms of four water molecules. The coordination of the Na⁺ cation is distorted octahedral. The water molecules bridge adjacent metal cations, forming polymeric layers parallel to (100). The structure is stabilized by an extensive network of O—H⋯O hydrogen bonds.

Related literature

Tin complexes with organic ligands have been studied intensively due to their biological activity, see, for example: Shahzadi et al. (2007 ▶). For 2-methylbenzoic and 4-methylbenzoic acids as potent allergic sensitizers when applied to human skin, see: Emmet & Suskind (1973 ▶), and as inhibitors of lettuce fruit germination, see: Reynolds (1978 ▶). Sodium 2-methylbenzoate has been studied as a precursor in the synthesis of biologically active tin(IV) complexes. For the structure of a sodium complex with a 2-methyl-3,5-dinitrobenzoate ligand, see: Danish et al. (2010 ▶).

Experimental

Crystal data

[Na(C₈H₇O₂)(H₂O)₂]
M _r = 194.16
Monoclinic,
a = 16.145 (3) Å
b = 8.1155 (16) Å
c = 7.3986 (15) Å
β = 92.98 (3)°
V = 968.1 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.14 mm⁻¹
T = 293 K
0.55 × 0.41 × 0.11 mm

Data collection

Kuma KM-4 four-circle diffractometer
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008 ▶) T _min = 0.952, T _max = 0.991
3057 measured reflections
2845 independent reflections
1919 reflections with I > 2σ(I)
R _int = 0.024
3 standard reflections every 200 reflections intensity decay: 0.8%

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.141
S = 1.02
2845 reflections
151 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.44 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: KM-4 Software (Kuma, 1996 ▶); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma, 2001 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810010536/wm2315sup1.cif

e-66-0m459-sup1.cif^{(16.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810010536/wm2315Isup2.hkl

e-66-0m459-Isup2.hkl^{(139.7KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Na1—O4	2.3599 (13)
Na1—O4ⁱ	2.3689 (13)
Na1—O1	2.4141 (13)
Na1—O3	2.4245 (13)
Na1—O3ⁱⁱ	2.5086 (13)
Na1—O2	2.5387 (14)

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H42⋯O1ⁱⁱⁱ	0.84 (3)	1.94 (3)	2.7582 (17)	163 (2)
O4—H41⋯O2^iv	0.76 (3)	2.03 (3)	2.7874 (17)	171 (2)
O3—H31⋯O1^v	0.88 (3)	1.97 (3)	2.7716 (16)	151 (2)
O3—H32⋯O2ⁱ	0.77 (3)	2.10 (3)	2.8265 (16)	158 (2)

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

Acknowledgments

MD acknowledges the Australian Government for the award of an Endeavour Post Doctoral Fellowship for the year 2009–2010.

supplementary crystallographic information

Comment

2-methylbenzoic and 4-methylbenzoic acids were studied as potent allergic sensitizers when applied to human skin (Emmet & Suskind, 1973). They are also used for the inhibition of lettuce fruit germination (Reynolds, 1978). The title compound was isolated as an intermediate during synthesis of biologically active organotin carboxylates (Shahzadi et al., 2007).

In the polymeric structure of the title compound, [Na(C₈H₇O₂)(H₂O)₂]_n, each sodium ion is coordinated by the carboxylic O atoms of the bidentate anion and by four bridging water O atoms (Fig.1). The coordination geometry around the Na⁺ cation is distorted octahedral with the equatorial plane composed of the carboxylate atoms O1 and O2 and the symmetry-related water O4 and O4ⁱ atoms [r.m.s. is 0.0580 (2) Å]. Water O3 and O3ⁱⁱ atoms are at the apical positions. The resulting coordination differs from the one reported in the structure of the Na⁺ complex with the 2-methyl-3,5-dinitrobenzoate anion. Here the metal exhibits coordination number 7 (Danish et al., 2010). The 2-methylbenzoate ring in the title compound is planar with a r.m.s. of 0.0089 (2) Å; the carboxylic group C17/O1/O2 makes an dihedral angle of 37.1 (2)° with the aromatic ring. Na⁺ cations form sheets parallel to the (100) plane in which they are grouped into pairs (Fig. 2). In such a pair, Na⁺ cations are coordinated by ligands with their 2-methylbenzoate rings pointing in the same direction but twisted by an angle of 73.0 (2)° relative to each other. Water O atoms bridge in two directions: via O4 atoms along the b axis and via O3 atoms along the c axis. Water molecules act as donors and carboxylate O atoms as acceptors in a network of O—H··· O hydrogen bonds that consolidate the crystal structure. Geometrical parameters of the hydrogen bonding are listed in Table 2.

Experimental

50 ml of an aqueous solution containing 0.0147 mmol of 2-methylbenzoic acid were added dropwise with continuous stirring at room trmperature to 50 ml of an aqueous solution of sodium bicarbonate (0.0147 mmol). The mixture was then refluxed for 3 hours, cooled to room temperature and concentrated under reduced pressure to afford a dry solid mass which was then purified by re-crystallization from a distilled water-ethanol (4:1) mixture to obtain single crystals.