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Acta Cryst. (2008). E64, m32    [ doi:10.1107/S1600536807062460 ]

Diaquabis(4-methylbenzoato-[kappa]O)zinc(II)

D.-Y. Ma, G.-H. Deng and W.-D. Song

Abstract top

The Zn atom in the title mononuclear complex, [Zn(C8H7O2)2(H2O)2], lies on a special position of site symmetry 2. The carboxylate group binds in a monodentate manner so that the geometry is best described as tetrahedral. Adjacent molecules are linked by O-H...O hydrogen bonds into a three-dimensional network.

Comment top

In the structural investigation of 4-methylbenzate complexes, it has been found that the 4-methylbenzoic acid functions as a multidentate ligand [(Song et al. (2007)], with versatile binding and coordination modes. In this paper, we report the crystal structure of the title compound, (I), a new Zn complex obtained by the reaction of 4-methylbenzoic acid with zinc chloride in alkaline aqueous solution.

As illustrated in Figure 1, the ZnII atom, possesses crystallogarphically imposed C2 symmetry, which is coordinated by two O atoms from two 4-methylbenzate ligands and two water molecules, and displays a tetrahedral geometry. Intermolecular O—H···O hydrogen bonding interactions (Table 1) between the coordinated water molecules and the carboxyl O atoms of 4-methylbenzate ligands stabilize the structural packing (Fig. 2).

Related literature top

For related literature, see: Song et al. (2007).

Experimental top

A mixture of zinc nitrate(1 mmol), 4-methylbenzoic acid (1 mmol) NaOH (1.5 mmol) and H2O (12 ml) was placed in a 23 ml Teflon reactor, which was heated to 433 K for three days and then cooled to room temperature at a rate of 10 K h-1. The crystals obtained were washed with water and dryed in air.

Refinement top

Carbon-bound H atoms were placed at calculated positions and were treated as riding on the parent C atoms with C—H = 0.93 - 0.97 Å, and with Uiso(H) = 1.2 Ueq(C). Water H atoms were tentatively located in difference Fourier maps and were refined with distance restraints of O–H = 0.82 Å and H···H = 1.29 Å, each within a standard deviation of 0.01 Å, and with Uiso(H) = 1.5 Ueq(O).

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTLXP (Bruker, 2004); software used to prepare material for publication: SHELXTLXP (Bruker, 2004).

Figures top
[Figure 1] Fig. 1. The structure of (I), showing the atomic numbering scheme. Non-H atoms are shown with 30% probability displacement ellipsoids. Unlabeled atoms are related to the labelled atoms by the symmetry operator (-x, y, 0.5 - z).
[Figure 2] Fig. 2. A packing view of the title compound. The intermolecluar hydrogen bonds are shown as dashed lines.
Diaquabis(4-methylbenzoato-κO)zinc(II) top
Crystal data top
[Zn(C8H7O2)2(H2O)2]F000 = 768
Mr = 371.70Dx = 1.574 Mg m−3
Monoclinic, C2/cMo Kα radiation
λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 3600 reflections
a = 26.8432 (5) Åθ = 3.0–27.5º
b = 5.06000 (10) ŵ = 1.59 mm−1
c = 12.0609 (2) ÅT = 273 (2) K
β = 106.8060 (10)ºBlock, colorless
V = 1568.22 (5) Å30.32 × 0.29 × 0.26 mm
Z = 4
Data collection top
Bruker APEXII area-detector
diffractometer		1784 independent reflections
Radiation source: fine-focus sealed tube1566 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.036
T = 273(2) Kθmax = 27.5º
φ and ω scanθmin = 3.2º
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −34→34
Tmin = 0.605, Tmax = 0.660k = −6→6
9051 measured reflectionsl = −15→15
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.031H atoms treated by a mixture of
independent and constrained refinement
wR(F2) = 0.076  w = 1/[σ2(Fo2) + (0.0378P)2 + 0.8633P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
1784 reflectionsΔρmax = 0.25 e Å−3
112 parametersΔρmin = −0.42 e Å−3
3 restraintsExtinction correction: none
Primary atom site location: structure-invariant direct methods
Crystal data top
[Zn(C8H7O2)2(H2O)2]V = 1568.22 (5) Å3
Mr = 371.70Z = 4
Monoclinic, C2/cMo Kα
a = 26.8432 (5) ŵ = 1.59 mm−1
b = 5.06000 (10) ÅT = 273 (2) K
c = 12.0609 (2) Å0.32 × 0.29 × 0.26 mm
β = 106.8060 (10)º
Data collection top
Bruker APEXII area-detector
diffractometer		1784 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		1566 reflections with I > 2σ(I)
Tmin = 0.605, Tmax = 0.660Rint = 0.036
9051 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0313 restraints
wR(F2) = 0.076H atoms treated by a mixture of
independent and constrained refinement
S = 1.05Δρmax = 0.25 e Å−3
1784 reflectionsΔρmin = −0.42 e Å−3
112 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.06512 (8)0.6273 (4)0.40073 (18)0.0311 (4)
C20.10484 (7)0.4299 (4)0.46142 (17)0.0300 (4)
C30.10475 (9)0.3264 (4)0.56687 (19)0.0409 (5)
H30.07950.38130.60090.049*
C40.14146 (9)0.1422 (5)0.6231 (2)0.0437 (5)
H40.14080.07710.69480.052*
C50.17921 (8)0.0533 (4)0.5741 (2)0.0384 (5)
C60.17872 (9)0.1556 (5)0.4675 (2)0.0463 (6)
H60.20360.09850.43290.056*
C70.14237 (8)0.3399 (5)0.4110 (2)0.0416 (5)
H70.14290.40440.33910.050*
C80.21820 (10)−0.1520 (5)0.6349 (2)0.0550 (6)
H8A0.2226−0.14450.71660.082*
H8B0.2510−0.11830.62040.082*
H8C0.2059−0.32430.60620.082*
O10.05926 (5)0.6655 (3)0.29258 (12)0.0356 (3)
O20.03766 (6)0.7481 (3)0.45086 (13)0.0415 (4)
O1W0.02917 (7)1.2004 (3)0.16969 (14)0.0450 (4)
H1W0.0402 (11)1.342 (3)0.199 (2)0.067*
H2W0.0326 (10)1.199 (5)0.1058 (12)0.067*
Zn10.00000.92389 (6)0.25000.03485 (13)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0344 (10)0.0256 (9)0.0297 (11)−0.0033 (8)0.0038 (9)−0.0014 (7)
C20.0319 (9)0.0304 (9)0.0257 (10)0.0002 (8)0.0053 (8)−0.0020 (8)
C30.0470 (12)0.0430 (11)0.0362 (12)0.0136 (10)0.0177 (10)0.0066 (9)
C40.0527 (13)0.0423 (12)0.0365 (13)0.0112 (10)0.0135 (11)0.0113 (9)
C50.0369 (11)0.0322 (10)0.0392 (12)0.0039 (9)0.0000 (9)−0.0018 (9)
C60.0383 (11)0.0568 (13)0.0453 (14)0.0146 (11)0.0142 (11)−0.0009 (11)
C70.0425 (12)0.0514 (12)0.0328 (12)0.0069 (10)0.0139 (10)0.0041 (10)
C80.0494 (14)0.0459 (13)0.0588 (17)0.0159 (11)−0.0015 (12)−0.0005 (12)
O10.0428 (8)0.0325 (7)0.0296 (8)0.0029 (6)0.0074 (6)0.0073 (6)
O20.0459 (8)0.0389 (8)0.0379 (9)0.0135 (7)0.0094 (7)−0.0002 (7)
O1W0.0727 (11)0.0285 (7)0.0383 (9)−0.0127 (7)0.0232 (9)−0.0040 (6)
Zn10.0361 (2)0.02136 (17)0.0484 (2)0.0000.01423 (16)0.000
Geometric parameters (Å, °) top
C1—O21.241 (2)C6—H60.9300
C1—O11.283 (2)C7—H70.9300
C1—C21.490 (3)C8—H8A0.9600
C2—C31.376 (3)C8—H8B0.9600
C2—C71.395 (3)C8—H8C0.9600
C3—C41.383 (3)O1—Zn12.0078 (14)
C3—H30.9300O1W—Zn11.9867 (14)
C4—C51.387 (3)O1W—H1W0.813 (9)
C4—H40.9300O1W—H2W0.803 (9)
C5—C61.383 (3)Zn1—O1Wi1.9867 (14)
C5—C81.506 (3)Zn1—O1i2.0078 (14)
C6—C71.379 (3)
O2—C1—O1120.38 (18)C6—C7—H7119.9
O2—C1—C2122.17 (19)C2—C7—H7119.9
O1—C1—C2117.43 (17)C5—C8—H8A109.5
C3—C2—C7118.26 (19)C5—C8—H8B109.5
C3—C2—C1121.13 (17)H8A—C8—H8B109.5
C7—C2—C1120.59 (18)C5—C8—H8C109.5
C2—C3—C4121.21 (19)H8A—C8—H8C109.5
C2—C3—H3119.4H8B—C8—H8C109.5
C4—C3—H3119.4C1—O1—Zn1102.32 (12)
C3—C4—C5121.0 (2)Zn1—O1W—H1W123.8 (18)
C3—C4—H4119.5Zn1—O1W—H2W129.3 (18)
C5—C4—H4119.5H1W—O1W—H2W106.9 (15)
C6—C5—C4117.58 (19)O1Wi—Zn1—O1W90.48 (9)
C6—C5—C8121.9 (2)O1Wi—Zn1—O1i100.86 (7)
C4—C5—C8120.5 (2)O1W—Zn1—O1i136.77 (7)
C7—C6—C5121.8 (2)O1Wi—Zn1—O1136.77 (7)
C7—C6—H6119.1O1W—Zn1—O1100.86 (6)
C5—C6—H6119.1O1i—Zn1—O198.74 (8)
C6—C7—C2120.1 (2)
Symmetry codes: (i) −x, y, −z+1/2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O1ii0.813 (9)1.973 (10)2.774 (2)168 (3)
O1W—H2W···O2iii0.803 (9)1.931 (11)2.726 (2)171 (3)
Symmetry codes: (ii) x, y+1, z; (iii) x, −y+2, z−1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O1i0.813 (9)1.973 (10)2.774 (2)168 (3)
O1W—H2W···O2ii0.803 (9)1.931 (11)2.726 (2)171 (3)
Symmetry codes: (i) x, y+1, z; (ii) x, −y+2, z−1/2.
Acknowledgements top

The authors acknowledge South China University of Technology and Guang Dong Ocean University for supporting this work.

references
References top

Bruker (2004). APEX2, SMART and SHELXTL-XP. Bruker AXS Inc., Madison, Wisconsin, USA.

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of Göttingen, Germany.

Song, W.-D., Gu, C.-S., Hao, X.-M. & Liu, J.-W. (2007). Acta Cryst. E63, m1023–m1024.