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Acta Crystallogr Sect E Struct Rep Online. 2008 April 1; 64(Pt 4): m581.
Published online 2008 March 29. doi:  10.1107/S1600536808006624
PMCID: PMC2961002

Hexaaqua­zinc(II) dipicrate

Abstract

In the title compound, [Zn(H2O)6](C6H2N3O7)2, the ZnII ion is located on an inversion center and is coordinated by six water mol­ecules in an octa­hedral geometry. The picrate anions have no coordination inter­actions with the ZnII atom. The three nitro groups are twisted away from the attached benzene ring by19.8 (3), 6.5 (4) and 28.6 (3)°. There are numerous O—H(...)O hydrogen bonds in the crystal structure.

Related literature

For related literature, see: Gartland et al. (1974 [triangle]); Herbstein et al. (1977 [triangle]); Liu et al. (2008 [triangle]); Maartmann-Moe (1969 [triangle]); Yang et al. (2001 [triangle]).

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Object name is e-64-0m581-scheme1.jpg

Experimental

Crystal data

  • [Zn(H2O)6](C6H2N3O7)2
  • M r = 629.68
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-0m581-efi1.jpg
  • a = 7.8571 (4) Å
  • b = 8.3311 (6) Å
  • c = 8.9897 (7) Å
  • α = 89.8350 (11)°
  • β = 83.097 (1)°
  • γ = 72.8370 (9)°
  • V = 557.84 (7) Å3
  • Z = 1
  • Mo Kα radiation
  • μ = 1.22 mm−1
  • T = 293 (2) K
  • 0.13 × 0.11 × 0.10 mm

Data collection

  • Nonius MACH-3 diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.854, T max = 0.886
  • 2441 measured reflections
  • 1971 independent reflections
  • 1908 reflections with I > 2σ(I)
  • R int = 0.006
  • 2 standard reflections frequency: 60 min intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.031
  • wR(F 2) = 0.087
  • S = 1.14
  • 1971 reflections
  • 196 parameters
  • 4 restraints
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.42 e Å−3
  • Δρmin = −0.71 e Å−3

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 [triangle]); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1996 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: PLATON (Spek, 2003 [triangle]); software used to prepare material for publication: SHELXL97.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808006624/ci2563sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808006624/ci2563Isup2.hkl

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

Acknowledgments

The authors thank the UGC for the SAP programme and the DST for the FIST programme.

supplementary crystallographic information

Comment

Picric acid forms salts with many organic and metallic cations (Gartland et al., 1974). Picrates with various degrees of hydration are formed by metals (e.g. Li, Na), the alkaline earths (e.g. Cd, Hg) and various transition metals (e.g. Al, Y). Crystal structures have been reported for isomorphous NH4 and K picrates (Maartmann-Moe, 1969), thallium picrate (Herbstein et al., 1977) and recently for manganese picrate (Liu et al., 2008). The present work reports the crystal structure of the title compound, a zinc picrate. This work is part of a systematic investigation on the structures of the metal complexes of picric acid.

In the crystal structure of the title compound, each ZnII ion is coordinated by the O atoms of six water molecules and not by the O atoms from the picrate anions. The Zn—O distances range from 2.0297 (16) to 2.1126 (17) Å. The coordination polyhedra around the ZnII ion can be described as a distorted octahedron. The picrate anion adopts a keto form with a C1—O1 bond distance of 1.242 (3) Å; the C6—C1 [1.457 (3) Å] and C2—C1 [1.456 (3) Å] bond distances are longer than the other C—C bond lengths of the benzene ring. The three nitro groups are twisted out of the attached benzene ring by 19.8 (3)° [N1/O2/O3], 6.5 (4)° [N2/O4/O5] and 28.6 (3)° [N3/O6/O7]. The twisting of the nitro groups may be attributed to the O—H···O hydrogen bonding interactions taking place between water and picrate O atoms. The C2—C1—C6 bond angle of 111.20 (18)° is narrower than the corresponding angle in picric acid (116.4 (5)°; Yang et al., 2001).

The packing of molecules is governed by large number of O—H···O hydrogen bonds (Table 1). π···π interactions are observed between the benzene rings of inversion related picrate ions, with a centroid to centroid distance of 3.6268 (11) Å (Fig. 2).

Experimental

Colourless needle shaped single crystals of the title compound were grown from a saturated aqueous solution containing picric acid and zinc chloride in a 1:1 stoichiometric ratio.

Refinement

O-bound H atoms were located in a difference Fourier map and their positional parameters were refined, with Uiso(H) = 1.5Ueq(O). Some of the O—H distances were restrained to 0.85 (2) Å. C-bound H atoms were placed at calculated positions and allowed to ride on their carrier atoms, with C—H = 0.93 Å, and Uiso = 1.2Ueq(C).

Figures

Fig. 1.
The molecular structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme. Atoms labeled with the suffix a and double prime (") are generated by the symmetry operations (-x, 1 - y, 1 - z) and (1 - x,1 ...
Fig. 2.
A packing diagram of the title compound. Dashed lines indicate π-π interactions.

Crystal data

[Zn(H2O)6](C6H2N3O7)2Z = 1
Mr = 629.68F000 = 320
Triclinic, P1Dx = 1.874 Mg m3
Hall symbol: -P 1Mo Kα radiation λ = 0.71073 Å
a = 7.8571 (4) ÅCell parameters from 25 reflections
b = 8.3311 (6) Åθ = 2–25º
c = 8.9897 (7) ŵ = 1.22 mm1
α = 89.8350 (11)ºT = 293 (2) K
β = 83.097 (1)ºNeedle, colourless
γ = 72.8370 (9)º0.13 × 0.11 × 0.10 mm
V = 557.84 (7) Å3

Data collection

Nonius MACH-3 diffractometerRint = 0.006
Radiation source: fine-focus sealed tubeθmax = 25.0º
Monochromator: graphiteθmin = 2.3º
T = 293(2) Kh = −1→9
ω–2θ scansk = −9→9
Absorption correction: ψ scan(North et al., 1968)l = −10→10
Tmin = 0.854, Tmax = 0.8862 standard reflections
2441 measured reflections every 60 min
1971 independent reflections intensity decay: none
1908 reflections with I > 2σ(I)

Refinement

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) = 0.087  w = 1/[σ2(Fo2) + (0.0559P)2 + 0.2704P] where P = (Fo2 + 2Fc2)/3
S = 1.14(Δ/σ)max = 0.001
1971 reflectionsΔρmax = 0.43 e Å3
196 parametersΔρmin = −0.71 e Å3
4 restraintsExtinction correction: none
Primary atom site location: structure-invariant direct methods

Special details

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)

xyzUiso*/Ueq
Zn10.00000.50000.50000.02629 (14)
O1W0.2724 (2)0.4246 (2)0.4648 (2)0.0388 (4)
H1WA0.325 (5)0.498 (5)0.458 (4)0.058*
H1WB0.328 (5)0.351 (5)0.513 (4)0.058*
O2W−0.0055 (3)0.5054 (2)0.73549 (19)0.0421 (4)
H2WB0.085 (3)0.504 (5)0.774 (4)0.063*
H2WA−0.055 (5)0.439 (4)0.775 (4)0.063*
O3W−0.0111 (2)0.7546 (2)0.4830 (2)0.0404 (4)
H3WA0.014 (5)0.812 (4)0.549 (3)0.061*
H3WB−0.104 (3)0.817 (4)0.455 (4)0.061*
O10.6551 (2)−0.1387 (2)0.37983 (19)0.0378 (4)
O20.8538 (3)0.0707 (2)0.3227 (3)0.0595 (6)
O30.7109 (3)0.3187 (3)0.2651 (3)0.0595 (6)
O40.2551 (3)0.3894 (2)−0.0507 (2)0.0517 (5)
O50.0834 (3)0.2284 (3)−0.0310 (2)0.0547 (5)
O60.4083 (3)−0.3049 (3)0.3983 (2)0.0514 (5)
O70.2971 (3)−0.3042 (3)0.1909 (2)0.0571 (5)
N10.7226 (3)0.1697 (2)0.2785 (2)0.0353 (4)
N20.2129 (3)0.2680 (3)0.0013 (2)0.0380 (5)
N30.3679 (3)−0.2413 (3)0.2789 (2)0.0350 (4)
C10.5553 (3)−0.0462 (3)0.2971 (2)0.0265 (4)
C20.5767 (3)0.1112 (3)0.2393 (2)0.0275 (4)
C30.4649 (3)0.2134 (3)0.1486 (2)0.0303 (5)
H30.48330.31430.11780.036*
C40.3249 (3)0.1648 (3)0.1037 (2)0.0302 (5)
C50.2933 (3)0.0163 (3)0.1492 (2)0.0304 (5)
H50.1993−0.01540.11730.037*
C60.4035 (3)−0.0836 (3)0.2424 (2)0.0278 (4)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Zn10.0234 (2)0.0250 (2)0.0316 (2)−0.00531 (14)−0.01323 (14)0.00959 (13)
O1W0.0258 (8)0.0363 (9)0.0567 (11)−0.0088 (7)−0.0161 (7)0.0218 (8)
O2W0.0460 (11)0.0465 (10)0.0327 (9)−0.0074 (8)−0.0172 (8)0.0094 (7)
O3W0.0395 (10)0.0272 (9)0.0598 (11)−0.0089 (7)−0.0290 (8)0.0117 (8)
O10.0341 (9)0.0369 (9)0.0472 (10)−0.0110 (7)−0.0233 (7)0.0217 (7)
O20.0513 (12)0.0418 (11)0.0980 (16)−0.0184 (9)−0.0471 (11)0.0189 (10)
O30.0736 (14)0.0418 (11)0.0806 (15)−0.0325 (10)−0.0394 (12)0.0258 (10)
O40.0565 (12)0.0461 (11)0.0510 (11)−0.0064 (9)−0.0245 (9)0.0264 (9)
O50.0469 (11)0.0612 (12)0.0593 (12)−0.0097 (10)−0.0363 (10)0.0197 (10)
O60.0471 (11)0.0599 (12)0.0616 (12)−0.0293 (9)−0.0297 (9)0.0399 (10)
O70.0721 (14)0.0606 (13)0.0585 (12)−0.0428 (11)−0.0275 (11)0.0166 (10)
N10.0406 (11)0.0325 (10)0.0379 (10)−0.0134 (9)−0.0182 (9)0.0084 (8)
N20.0372 (11)0.0385 (11)0.0298 (10)0.0053 (9)−0.0136 (8)0.0075 (8)
N30.0278 (10)0.0398 (11)0.0412 (11)−0.0128 (8)−0.0119 (8)0.0136 (9)
C10.0245 (10)0.0266 (10)0.0260 (10)−0.0023 (8)−0.0079 (8)0.0063 (8)
C20.0292 (11)0.0272 (10)0.0267 (10)−0.0065 (9)−0.0105 (8)0.0047 (8)
C30.0359 (12)0.0257 (10)0.0262 (10)−0.0028 (9)−0.0083 (9)0.0058 (8)
C40.0292 (11)0.0316 (11)0.0244 (10)0.0022 (9)−0.0107 (8)0.0065 (8)
C50.0232 (10)0.0387 (12)0.0270 (10)−0.0034 (9)−0.0087 (8)0.0046 (9)
C60.0257 (10)0.0300 (11)0.0272 (10)−0.0062 (8)−0.0069 (8)0.0083 (8)

Geometric parameters (Å, °)

Zn1—O1Wi2.0297 (16)O4—N21.228 (3)
Zn1—O1W2.0297 (16)O5—N21.224 (3)
Zn1—O3Wi2.1025 (16)O6—N31.230 (3)
Zn1—O3W2.1025 (16)O7—N31.221 (3)
Zn1—O2Wi2.1126 (17)N1—C21.451 (3)
Zn1—O2W2.1126 (17)N2—C41.451 (3)
O1W—H1WA0.83 (4)N3—C61.451 (3)
O1W—H1WB0.80 (4)C1—C21.456 (3)
O2W—H2WB0.822 (18)C1—C61.457 (3)
O2W—H2WA0.825 (18)C2—C31.374 (3)
O3W—H3WA0.837 (18)C3—C41.381 (3)
O3W—H3WB0.824 (19)C3—H30.93
O1—C11.242 (3)C4—C51.383 (3)
O2—N11.223 (3)C5—C61.374 (3)
O3—N11.224 (3)C5—H50.93
O1Wi—Zn1—O1W180.0O3—N1—C2118.43 (19)
O1Wi—Zn1—O3Wi92.05 (7)O5—N2—O4123.3 (2)
O1W—Zn1—O3Wi87.95 (7)O5—N2—C4118.6 (2)
O1Wi—Zn1—O3W87.95 (7)O4—N2—C4118.1 (2)
O1W—Zn1—O3W92.05 (7)O7—N3—O6122.8 (2)
O3Wi—Zn1—O3W180.0O7—N3—C6118.70 (19)
O1Wi—Zn1—O2Wi92.82 (8)O6—N3—C6118.5 (2)
O1W—Zn1—O2Wi87.18 (8)O1—C1—C2124.7 (2)
O3Wi—Zn1—O2Wi93.38 (8)O1—C1—C6124.1 (2)
O3W—Zn1—O2Wi86.62 (8)C2—C1—C6111.20 (18)
O1Wi—Zn1—O2W87.18 (8)C3—C2—N1115.76 (19)
O1W—Zn1—O2W92.82 (8)C3—C2—C1124.3 (2)
O3Wi—Zn1—O2W86.62 (8)N1—C2—C1119.89 (18)
O3W—Zn1—O2W93.38 (8)C2—C3—C4119.3 (2)
O2Wi—Zn1—O2W180.0C2—C3—H3120.3
Zn1—O1W—H1WA118 (2)C4—C3—H3120.3
Zn1—O1W—H1WB120 (3)C3—C4—C5121.54 (19)
H1WA—O1W—H1WB107 (3)C3—C4—N2119.3 (2)
Zn1—O2W—H2WB121 (3)C5—C4—N2119.1 (2)
Zn1—O2W—H2WA111 (3)C6—C5—C4118.8 (2)
H2WB—O2W—H2WA112 (4)C6—C5—H5120.6
Zn1—O3W—H3WA125 (3)C4—C5—H5120.6
Zn1—O3W—H3WB116 (2)C5—C6—N3115.6 (2)
H3WA—O3W—H3WB104 (3)C5—C6—C1124.8 (2)
O2—N1—O3121.6 (2)N3—C6—C1119.51 (18)
O2—N1—C2119.98 (19)
O2—N1—C2—C3−160.3 (2)O5—N2—C4—C56.7 (3)
O3—N1—C2—C319.3 (3)O4—N2—C4—C5−172.1 (2)
O2—N1—C2—C120.3 (3)C3—C4—C5—C60.6 (3)
O3—N1—C2—C1−160.1 (2)N2—C4—C5—C6177.90 (19)
O1—C1—C2—C3−179.5 (2)C4—C5—C6—N3−176.93 (19)
C6—C1—C2—C31.8 (3)C4—C5—C6—C1−0.7 (3)
O1—C1—C2—N1−0.2 (3)O7—N3—C6—C526.2 (3)
C6—C1—C2—N1−178.87 (19)O6—N3—C6—C5−152.9 (2)
N1—C2—C3—C4178.65 (19)O7—N3—C6—C1−150.2 (2)
C1—C2—C3—C4−2.0 (3)O6—N3—C6—C130.7 (3)
C2—C3—C4—C50.7 (3)O1—C1—C6—C5−179.1 (2)
C2—C3—C4—N2−176.59 (19)C2—C1—C6—C5−0.4 (3)
O5—N2—C4—C3−176.0 (2)O1—C1—C6—N3−3.0 (3)
O4—N2—C4—C35.2 (3)C2—C1—C6—N3175.65 (19)

Symmetry codes: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O3W—H3WB···O1ii0.82 (2)2.02 (2)2.781 (2)153 (3)
O3W—H3WB···O2ii0.82 (2)2.38 (3)2.972 (3)130 (3)
O3W—H3WA···O2iii0.84 (2)2.07 (2)2.880 (3)164 (3)
O2W—H2WB···O3iii0.82 (2)2.48 (3)3.083 (3)131 (3)
O1W—H1WA···O6iv0.83 (4)1.99 (4)2.799 (3)164 (3)
O1W—H1WB···O1v0.80 (4)1.99 (4)2.705 (2)149 (3)
O1W—H1WB···O6v0.80 (4)2.24 (4)2.839 (2)132 (3)
O2W—H2WB···O4vi0.82 (2)2.22 (3)2.931 (3)144 (3)
O2W—H2WA···O5vi0.82 (2)2.57 (3)3.097 (3)123 (3)
O2W—H2WA···O7vii0.82 (2)2.46 (2)3.223 (3)154 (3)

Symmetry codes: (ii) x−1, y+1, z; (iii) −x+1, −y+1, −z+1; (iv) x, y+1, z; (v) −x+1, −y, −z+1; (vi) x, y, z+1; (vii) −x, −y, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CI2563).

References

  • Enraf–Nonius (1994). CAD-4 EXPRESS Enraf–Nonius, Delft, The Netherlands.
  • Gartland, G. L., Freeman, G. R. & Bugg, C. E. (1974). Acta Cryst. B30, 1841–1849.
  • Harms, K. & Wocadlo, S. (1996). XCAD4 University of Marburg, Germany.
  • Herbstein, F. H., Kapon, M. & Wielinski, S. (1977). Acta Cryst. B33, 649–654.
  • Liu, C., Shi, X., Du, B., Wu, C. & Zhang, M. (2008). Acta Cryst. E64, m270–m271. [PMC free article] [PubMed]
  • Maartmann-Moe, K. (1969). Acta Cryst. B25, 1452–1460.
  • North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2003). J. Appl. Cryst.36, 7–13.
  • Yang, L., Zhang, T. L., Feng, C. G., Zhang, J. G. & Yu, K. B. (2001). Energ. Mater.9, 37–39.

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