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Acta Crystallogr Sect E Struct Rep Online. 2009 June 1; 65(Pt 6): m620.
Published online 2009 May 7. doi:  10.1107/S1600536809015049
PMCID: PMC2969625

Hexaaqua­cadmium(II) dipicrate monohydrate

Abstract

In the structure of the title compound, [Cd(H2O)6](C6H2N3O7)2·H2O, the CdII 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 CdII ion. The three nitro groups are twisted away from the attached benzene ring, making dihedral angles of 17.89 (3), 27.94 (4) and 13.65 (3)°. There are numerous O—H(...)O hydrogen bonds in the crystal structure, involving coordinated and uncoordinated water molecules.

Related literature

Picric acid forms salts with many organic and metallic cations, see: Gartland et al. (1974 [triangle]). Crystal structures have been reported for NH4 and K picrates (Maartmann-Moe, 1969 [triangle]), thallium picrate (Herbstein et al., 1977 [triangle]), manganese picrate (Liu et al., 2008 [triangle]) and zinc picrate (Natarajan et al., 2008 [triangle]). For bond angles in picric acid, see: Yang et al. (2001 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-0m620-scheme1.jpg

Experimental

Crystal data

  • [Cd(H2O)6](C6H2N3O7)2·H2O
  • M r = 712.75
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-65-0m620-efi1.jpg
  • a = 7.2823 (2) Å
  • b = 13.2249 (4) Å
  • c = 25.3798 (8) Å
  • V = 2444.27 (13) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 1.01 mm−1
  • T = 293 K
  • 0.18 × 0.15 × 0.11 mm

Data collection

  • Nonius MACH-3 diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.834, T max = 0.895
  • 2247 measured reflections
  • 2142 independent reflections
  • 1513 reflections with I > 2σ(I)
  • R int = 0.010
  • 2 standard reflections frequency: 60 min intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.027
  • wR(F 2) = 0.084
  • S = 1.16
  • 2142 reflections
  • 220 parameters
  • 2 restraints
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.54 e Å−3
  • Δρmin = −0.38 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, 2009 [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/S1600536809015049/bq2135sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809015049/bq2135Isup2.hkl

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

Acknowledgments

The authors thank the DST for the FIST program.

supplementary crystallographic information

Comment

Picric acid forms salts with many organic and metallic cations (Gartland et al., 1974). Crystal structures have been reported for isomorphous NH4 and K picrates (Maartmann-Moe, 1969), thallium picrate (Herbstein et al., 1977), recently for manganese picrate (Liu et al., 2008) and zinc picrate (Natarajan et al., 2008). This work is part of a systematic investigation on the structures of the metal complexes of picric acid.

In the structure of the title compound, each CdII ion is coordinated by the O atoms of six water molecules (Fig. 1). The Cd—O distances range from 2.219 (3)Å to 2.299 (3)Å. The coordination polyhedra around the CdII ion can be described as a distorted octahedron. The picrate anion adopts a keto form with a C6—O7 bond distance of 1.250 (4)Å; the C1—C6 [1.444 (5)Å] and C5—C6 [1.454 (5)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 17.89 (3)° [N1/O1/O2], 27.94 (4)° [N2/O5/O6] and 13.65 (3)° [N3/O3/O4]. The twisting of these nitro groups may be attributed to the O—H···O hydrogen bonding interactions taking place between water and picrate O atoms. The C5—C6—C1 bond angle (111.8 (3)°) is smaller than the corresponding angle in picric acid (116.4 (5)°; Yang et al., 2001). The packing of the molecules is governed by the large number of O—H···O hydrogen bonds (Table 1).

Experimental

Colorless needle-shaped single crystals of the title compound were grown from a saturated aqueous solution containing picric acid and cadmium 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). 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.

Crystal data

[Cd(H2O)6](C6H2N3O7)2·H2OF(000) = 1432
Mr = 712.75Dx = 1.937 Mg m3
Orthorhombic, PbnbMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2bc 2abCell parameters from 25 reflections
a = 7.2823 (2) Åθ = 3–25°
b = 13.2249 (4) ŵ = 1.01 mm1
c = 25.3798 (8) ÅT = 293 K
V = 2444.27 (13) Å3Block, colourless
Z = 40.18 × 0.15 × 0.11 mm

Data collection

Nonius MACH-3 diffractometer1513 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.010
graphiteθmax = 25.0°, θmin = 2.9°
ω–2θ scansh = 0→8
Absorption correction: ψ scan (North et al., 1968)k = 0→15
Tmin = 0.834, Tmax = 0.895l = −1→30
2247 measured reflections2 standard reflections every 60 min
2142 independent reflections intensity decay: none

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.084w = 1/[σ2(Fo2) + (0.0314P)2 + 3.7212P] where P = (Fo2 + 2Fc2)/3
S = 1.16(Δ/σ)max < 0.001
2142 reflectionsΔρmax = 0.54 e Å3
220 parametersΔρmin = −0.38 e Å3
2 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0029 (2)

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
Cd0.00000.50000.00000.03236 (15)
O110.1978 (4)0.5718 (3)0.05990 (11)0.0393 (7)
O10.4465 (5)0.2509 (2)0.11321 (10)0.0581 (9)
O50.6784 (4)0.6893 (2)0.18800 (10)0.0430 (7)
O70.4862 (4)0.4516 (2)0.10554 (9)0.0390 (7)
O20.3391 (4)0.1969 (2)0.18648 (10)0.0435 (7)
O60.5121 (4)0.6525 (2)0.12019 (9)0.0415 (7)
O40.5772 (5)0.5100 (2)0.34801 (10)0.0463 (7)
N30.5092 (4)0.4393 (2)0.32448 (11)0.0297 (7)
O8−0.0269 (6)0.3512 (2)0.04266 (13)0.0609 (10)
O90.2500 (5)0.4420 (3)−0.03995 (13)0.0554 (9)
O30.4428 (4)0.3650 (2)0.34660 (10)0.0430 (7)
O100.5209 (5)0.3302 (2)0.00923 (13)0.0457 (8)
N20.5770 (4)0.6320 (2)0.16356 (11)0.0301 (7)
C40.5398 (5)0.5320 (3)0.24176 (14)0.0280 (8)
H40.56940.58980.26080.034*
N10.4123 (5)0.2622 (2)0.15992 (11)0.0336 (7)
C20.4606 (5)0.3554 (3)0.23989 (13)0.0290 (8)
H20.43360.29580.25770.035*
C30.5024 (5)0.4423 (3)0.26750 (12)0.0279 (8)
C60.4911 (5)0.4481 (3)0.15474 (13)0.0272 (7)
C10.4592 (5)0.3581 (3)0.18566 (13)0.0286 (8)
C50.5328 (5)0.5350 (3)0.18776 (13)0.0258 (8)
H8W0.517 (8)0.337 (5)0.043 (3)0.09 (2)*
H1W0.172 (8)0.607 (4)0.081 (2)0.07 (2)*
H3W−0.009 (7)0.350 (4)0.074 (2)0.065 (16)*
H5W0.302 (7)0.475 (4)−0.0643 (19)0.063 (16)*
H2W0.276 (8)0.536 (4)0.0788 (19)0.067 (17)*
H6W0.317 (5)0.402 (3)−0.0255 (15)0.045 (13)*
H9W0.612 (8)0.349 (4)−0.0004 (19)0.06 (2)*
H4W−0.007 (7)0.297 (2)0.0302 (19)0.065 (17)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Cd0.0329 (2)0.0278 (2)0.0363 (2)0.00038 (17)−0.00396 (18)−0.00312 (16)
O110.0433 (17)0.0432 (17)0.0314 (14)0.0014 (14)−0.0075 (13)−0.0079 (14)
O10.109 (3)0.0353 (16)0.0295 (15)−0.0106 (17)0.0057 (16)−0.0099 (12)
O50.0509 (18)0.0310 (15)0.0470 (15)−0.0088 (13)−0.0122 (14)0.0002 (13)
O70.0649 (19)0.0298 (13)0.0221 (12)0.0003 (13)−0.0042 (13)−0.0018 (11)
O20.0614 (19)0.0269 (15)0.0423 (15)−0.0055 (14)−0.0051 (14)0.0004 (12)
O60.066 (2)0.0324 (14)0.0260 (13)−0.0018 (14)−0.0045 (13)0.0039 (11)
O40.0609 (18)0.0510 (18)0.0270 (13)−0.0151 (16)−0.0020 (13)−0.0087 (13)
N30.0297 (16)0.0375 (18)0.0220 (14)−0.0003 (15)−0.0011 (14)−0.0031 (13)
O80.118 (3)0.0330 (16)0.0312 (16)0.004 (2)−0.0078 (19)0.0040 (13)
O90.058 (2)0.063 (2)0.0451 (17)0.0244 (19)0.0174 (17)0.0129 (17)
O30.0582 (18)0.0428 (16)0.0281 (13)−0.0079 (15)−0.0016 (13)0.0068 (12)
O100.051 (2)0.0435 (17)0.0426 (19)−0.0074 (16)0.0016 (16)−0.0024 (14)
N20.0346 (16)0.0271 (16)0.0286 (15)0.0041 (14)0.0019 (14)−0.0006 (13)
C40.026 (2)0.0300 (17)0.0278 (18)0.0014 (15)−0.0025 (14)−0.0070 (15)
N10.0434 (19)0.0268 (16)0.0306 (16)0.0010 (15)−0.0037 (15)−0.0016 (14)
C20.033 (2)0.0288 (17)0.0255 (18)0.0020 (16)−0.0023 (14)0.0026 (14)
C30.0279 (17)0.0334 (19)0.0225 (16)0.0027 (16)−0.0020 (16)−0.0017 (14)
C60.0287 (18)0.0272 (17)0.0256 (17)0.0017 (15)−0.0010 (16)−0.0022 (14)
C10.035 (2)0.0238 (17)0.0268 (17)0.0012 (16)−0.0043 (15)−0.0030 (14)
C50.028 (2)0.0239 (16)0.0256 (16)0.0022 (14)−0.0013 (14)0.0004 (14)

Geometric parameters (Å, °)

Cd—O9i2.221 (3)O8—H3W0.79 (5)
Cd—O92.221 (3)O8—H4W0.80 (2)
Cd—O8i2.255 (3)O9—H5W0.85 (5)
Cd—O82.255 (3)O9—H6W0.81 (4)
Cd—O112.299 (3)O10—H8W0.87 (7)
Cd—O11i2.299 (3)O10—H9W0.75 (6)
O11—H1W0.73 (5)N2—C51.459 (5)
O11—H2W0.88 (6)C4—C51.372 (5)
O1—N11.220 (4)C4—C31.382 (5)
O5—N21.226 (4)C4—H40.9300
O7—C61.250 (4)N1—C11.467 (4)
O2—N11.219 (4)C2—C11.377 (5)
O6—N21.228 (4)C2—C31.380 (5)
O4—N31.216 (4)C2—H20.9300
N3—O31.231 (4)C6—C11.444 (5)
N3—C31.447 (4)C6—C51.454 (5)
O9i—Cd—O9180.00 (15)H5W—O9—H6W113 (5)
O9i—Cd—O8i89.37 (14)H8W—O10—H9W108 (5)
O9—Cd—O8i90.63 (14)O5—N2—O6123.3 (3)
O9i—Cd—O890.63 (14)O5—N2—C5117.6 (3)
O9—Cd—O889.37 (14)O6—N2—C5119.1 (3)
O8i—Cd—O8180.00 (16)C5—C4—C3119.3 (3)
O9i—Cd—O1193.97 (13)C5—C4—H4120.4
O9—Cd—O1186.03 (13)C3—C4—H4120.4
O8i—Cd—O1184.41 (13)O2—N1—O1122.7 (3)
O8—Cd—O1195.59 (13)O2—N1—C1117.9 (3)
O9i—Cd—O11i86.03 (13)O1—N1—C1119.4 (3)
O9—Cd—O11i93.97 (13)C1—C2—C3119.2 (3)
O8i—Cd—O11i95.59 (13)C1—C2—H2120.4
O8—Cd—O11i84.41 (13)C3—C2—H2120.4
O11—Cd—O11i180.00 (11)C2—C3—C4121.2 (3)
Cd—O11—H1W126 (5)C2—C3—N3119.5 (3)
Cd—O11—H2W123 (3)C4—C3—N3119.3 (3)
H1W—O11—H2W96 (5)O7—C6—C1124.7 (3)
O4—N3—O3123.4 (3)O7—C6—C5123.5 (3)
O4—N3—C3118.9 (3)C1—C6—C5111.8 (3)
O3—N3—C3117.7 (3)C2—C1—C6124.3 (3)
Cd—O8—H3W118 (4)C2—C1—N1115.1 (3)
Cd—O8—H4W126 (4)C6—C1—N1120.5 (3)
H3W—O8—H4W110 (5)C4—C5—C6124.1 (3)
Cd—O9—H5W122 (3)C4—C5—N2115.9 (3)
Cd—O9—H6W121 (3)C6—C5—N2119.9 (3)
C1—C2—C3—C41.1 (6)O2—N1—C1—C216.5 (5)
C1—C2—C3—N3−178.2 (3)O1—N1—C1—C2−163.9 (4)
C5—C4—C3—C20.8 (6)O2—N1—C1—C6−160.4 (3)
C5—C4—C3—N3−179.8 (3)O1—N1—C1—C619.2 (5)
O4—N3—C3—C2167.0 (3)C3—C4—C5—C6−1.1 (5)
O3—N3—C3—C2−14.0 (5)C3—C4—C5—N2−179.0 (3)
O4—N3—C3—C4−12.3 (5)O7—C6—C5—C4−179.6 (4)
O3—N3—C3—C4166.7 (3)C1—C6—C5—C4−0.4 (5)
C3—C2—C1—C6−2.9 (6)O7—C6—C5—N2−1.8 (5)
C3—C2—C1—N1−179.7 (3)C1—C6—C5—N2177.4 (3)
O7—C6—C1—C2−178.4 (4)O5—N2—C5—C426.6 (5)
C5—C6—C1—C22.5 (5)O6—N2—C5—C4−153.5 (3)
O7—C6—C1—N1−1.8 (6)O5—N2—C5—C6−151.4 (3)
C5—C6—C1—N1179.1 (3)O6—N2—C5—C628.5 (5)

Symmetry codes: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O11—H1W···O1ii0.73 (5)2.25 (6)2.923 (4)155 (6)
O8—H3W···O3iii0.79 (5)2.09 (5)2.882 (4)172 (5)
O8—H4W···O10iv0.80 (2)1.96 (2)2.758 (5)171 (5)
O9—H5W···O6v0.85 (5)2.59 (5)2.951 (4)107 (4)
O9—H5W···O7v0.85 (5)2.10 (5)2.905 (5)159 (5)
O10—H9W···O11v0.75 (6)2.30 (5)2.993 (5)154 (5)
C4—H4···O2vi0.932.573.195 (4)125
O11—H2W···O60.88 (6)2.54 (5)2.953 (4)109 (4)
O11—H2W···O70.88 (6)2.01 (6)2.877 (4)166 (5)
O9—H6W···O100.81 (4)1.97 (2)2.763 (5)167 (5)
O10—H8W···O10.87 (7)2.18 (7)2.891 (4)140 (5)
O10—H8W···O70.87 (7)2.20 (7)2.936 (4)142 (6)

Symmetry codes: (ii) −x+1/2, y+1/2, z; (iii) −x+1/2, y, −z+1/2; (iv) x−1/2, −y+1/2, −z; (v) −x+1, −y+1, −z; (vi) x, y+1/2, −z+1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BQ2135).

References

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  • Natarajan, S., Vijitha, K. V., Dhas, S. A. M. B., Suresh, J. & Lakshman, P. L. N. (2008). Acta Cryst. E64, m581. [PMC free article] [PubMed]
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  • Yang, L., Zhang, T. L., Feng, C. G., Zhang, J. G. & Yu, K. B. (2001). Energ. Mater 9, 37–39.

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