metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

trans-Di­aqua­bis­­[4-carb­oxy-5-carboxyl­ato-2-(pyridin-1-ium-4-yl)-1H-imidazol-1-ido-κ2N1,O5]cobalt(II)

aSchool of Chemistry and Environment, South China Normal University, Guangzhou 510006, People's Republic of China
*Correspondence e-mail: dh@scnu.edu.cn

(Received 8 July 2011; accepted 11 August 2011; online 17 August 2011)

In the title compound, [Co(C10H6N3O4)2(H2O)2], the CoII ion is coordinated by two O atoms of two water mol­ecules, two imidazole nitro­gen atoms and two carboxyl­ate O atoms of the two trans-standing chelate ligands, displaying a distorted octa­hedral coordination geometry. A three-dimensional supra­molecular framework is generated through N—H⋯O, O—H⋯N and O—H⋯O hydrogen-bonding inter­actions.

Related literature

For the chemistry of N-heterocyclic carb­oxy­lic acids, see: Peng et al. (2010[Peng, G., Qiu, Y. C., Liu, Z. H., Liu, B. & Deng, H. (2010). Cryst. Growth Des. 10, 114-121.]); Liu et al. (2005[Liu, Z., Chen, Y., Liu, P., Wang, J. & Huang, M. H. (2005). J. Solid State Chem. 178, 2306-2312.]). For the applications of 2-(pyridine-4-yl)-1H-4,5-imidazole­dicarb­oxy­lic acid, see: Li, Liu et al. (2009[Li, X., Liu, W., Wu, B.-L. & Zhang, H.-Y. (2009). Acta Cryst. E65, m820-m821.]); Sun et al. (2006[Sun, T., Ma, J.-P., Huang, R.-Q. & Dong, Y.-B. (2006). Acta Cryst. E62, o2751-o2752.]); Li, Wu et al. (2009[Li, X., Wu, B., Niu, C., Niu, Y. & Zhang, H. (2009). Cryst. Growth Des. 9, 3423-3431.]); Chen et al. (2010[Chen, L. Z., Huang, Y., Xiong, R. & Hu, H. J. (2010). J. Mol. Struct. 963, 16-21.]).

[Scheme 1]

Experimental

Crystal data
  • [Co(C10H6N3O4)2(H2O)2]

  • Mr = 559.32

  • Monoclinic, C 2/c

  • a = 7.4146 (17) Å

  • b = 20.190 (5) Å

  • c = 13.361 (3) Å

  • β = 97.383 (3)°

  • V = 1983.6 (8) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.95 mm−1

  • T = 296 K

  • 0.27 × 0.26 × 0.24 mm

Data collection
  • Bruker AXS SMART APEX CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.775, Tmax = 0.797

  • 4997 measured reflections

  • 1775 independent reflections

  • 1480 reflections with I > 2σ(I)

  • Rint = 0.032

Refinement
  • R[F2 > 2σ(F2)] = 0.035

  • wR(F2) = 0.088

  • S = 1.01

  • 1775 reflections

  • 181 parameters

  • 3 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.27 e Å−3

  • Δρmin = −0.43 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1W—H1WA⋯N2i 0.84 (2) 2.05 (2) 2.889 (3) 176 (4)
O1W—H1WB⋯O4ii 0.81 (2) 2.27 (2) 3.046 (3) 161 (4)
N3—H3⋯O4iii 0.91 (3) 1.86 (3) 2.754 (3) 170 (3)
O3—H3A⋯O2 1.20 (4) 1.25 (4) 2.451 (3) 172 (3)
Symmetry codes: (i) [-x+{\script{3\over 2}}, -y+{\script{1\over 2}}, -z+1]; (ii) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]; (iii) [-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}].

Data collection: APEX2 (Bruker, 2004[Bruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2004[Bruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Mixed N– and O-donor organic ligands, such as 1H-benzimidazole-5-carboxylic acid, has been investigated and proved to be a good choice to costruct novel coordination polymers (Peng et al., 2010; Liu et al., 2005). Another hybrid molecule 2-(pyridine-4-yl)-1H-4,5-imidazoledicarboxylic acid exhibits diverse coordination modes for its abundant potential donor atoms (Li, Liu et al., 2009; Sun et al., 2006; Li, Wu et al., 2009; Chen et al., 2010). In this work, we employed 2-(pyridine-4-yl)-1H-4,5-imidazoledicarboxylic acid as the building blocks to synthesize the title compound under hydrothermal condition. The centre metal ion Coii lies on an inversion centre and is coordinated by two imidazole nitrogen atoms, two O atoms of two water molecules and two carboxylate O atoms of the two trans-standing chelate ligands, displaying a distorted octahedral coordination geometry. The bond distances of Co—Ow and Co—Ocarboxylate are 2.092 (3)Å and 2.066 (3) Å, respectively. And the Co—N bond length is 2.168 (3)Å (Table 1). The dihedral angle between the pyridyl ring and the imidazole ring is about 13.98 (2)° (Table 1, Figure 1). Since there are many hydrogen bonding interactions, a three-dimensional supramolecular architecture is eventually formed via N—H···O, O—H···N and O—H···O hydrogen-bonding interactions (Table 2, Figure 2).

Related literature top

For the chemistry of N-heterocyclic carboxylic acids, see: Peng et al. (2010); Liu et al. (2005). For the applications of 2-(pyridine-4-yl)-1H-4,5-imidazoledicarboxylic acid, see: Li, Liu et al. (2009); Sun et al. (2006); Li, Wu et al. (2009); Chen et al. (2010).

Experimental top

A mixture of CoSO4(0.4 mmol, 0.062 g) and 2-(pyridine-4-yl)-1H-4,5-imidazoledicarboxylic acid (0.5 mmol, 0.115 g) together with water (10 ml) was sealed in a 23 ml Teflon-lined stainless steel reactor and heated at 160°C under autogenous pressure for 96 h. Then the mixture was cooled down to room temperature at a rate of 5°C/h, and brown block crystals were obtained in a yield of 39% based on Co.

Refinement top

H atoms bonded to C atoms were ideally positioned with C—H=0.93 Å, and displacement parameters set to 1.2 times of their carrier atoms. All H atoms attached to O and N atoms were located in difference density Fourier maps and H atoms of water were refined with the following distance restraints: O—H = 0.82 (2) Å and H—H = 1.35 (2) Å with Uiso(H) = 1.5 Ueq(O) and Uiso(H) = 1.2Ueq(N) respectively.

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, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The structure of (I), showing the atomic numbering scheme. Non-H atoms are shown as 50% probability displacement ellipsoids.
[Figure 2] Fig. 2. A packing view of (I) along the a axis, showing the hydrogen bonds.
trans-Diaquabis[4-carboxy-5-carboxylato-2-(pyridin-1-ium-4-yl)- 1H-imidazol-1-ido-κ2N1,O5]cobalt(II) top
Crystal data top
[Co(C10H6N3O4)2(H2O)2]F(000) = 1140
Mr = 559.32Dx = 1.873 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1775 reflections
a = 7.4146 (17) Åθ = 2.5–25.5°
b = 20.190 (5) ŵ = 0.95 mm1
c = 13.361 (3) ÅT = 296 K
β = 97.383 (3)°Block, brown
V = 1983.6 (8) Å30.27 × 0.26 × 0.24 mm
Z = 4
Data collection top
Bruker AXS SMART APEX CCD
diffractometer
1775 independent reflections
Radiation source: fine-focus sealed tube1480 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
ω scansθmax = 25.2°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 88
Tmin = 0.775, Tmax = 0.797k = 1724
4997 measured reflectionsl = 1515
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.035Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.088H atoms treated by a mixture of independent and constrained refinement
S = 1.01 w = 1/[σ2(Fo2) + (0.034P)2 + 5.2791P]
where P = (Fo2 + 2Fc2)/3
1775 reflections(Δ/σ)max = 0.021
181 parametersΔρmax = 0.27 e Å3
3 restraintsΔρmin = 0.43 e Å3
Crystal data top
[Co(C10H6N3O4)2(H2O)2]V = 1983.6 (8) Å3
Mr = 559.32Z = 4
Monoclinic, C2/cMo Kα radiation
a = 7.4146 (17) ŵ = 0.95 mm1
b = 20.190 (5) ÅT = 296 K
c = 13.361 (3) Å0.27 × 0.26 × 0.24 mm
β = 97.383 (3)°
Data collection top
Bruker AXS SMART APEX CCD
diffractometer
1775 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1480 reflections with I > 2σ(I)
Tmin = 0.775, Tmax = 0.797Rint = 0.032
4997 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0353 restraints
wR(F2) = 0.088H atoms treated by a mixture of independent and constrained refinement
S = 1.01Δρmax = 0.27 e Å3
1775 reflectionsΔρmin = 0.43 e Å3
181 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
C10.9792 (4)0.32925 (12)0.57368 (19)0.0187 (6)
C20.8527 (4)0.34198 (12)0.63981 (19)0.0193 (6)
C30.8791 (3)0.23737 (12)0.62348 (19)0.0178 (5)
C40.8456 (3)0.16716 (13)0.63859 (19)0.0193 (6)
C50.9082 (4)0.11718 (14)0.5791 (2)0.0257 (6)
H50.96950.12790.52480.031*
C60.8781 (4)0.05252 (15)0.6016 (2)0.0332 (7)
H60.91760.01930.56130.040*
C70.7298 (4)0.08204 (14)0.7376 (2)0.0282 (7)
H70.67020.06950.79180.034*
C80.7511 (4)0.14764 (13)0.7177 (2)0.0254 (6)
H80.70260.17950.75690.031*
C91.0837 (4)0.37354 (13)0.5147 (2)0.0234 (6)
C100.7965 (4)0.40581 (13)0.6804 (2)0.0240 (6)
Co11.25000.25000.50000.02030 (17)
N10.9989 (3)0.26264 (10)0.56502 (16)0.0176 (5)
N20.7881 (3)0.28357 (10)0.67008 (16)0.0203 (5)
N30.7934 (3)0.03578 (12)0.68026 (19)0.0290 (6)
H30.779 (4)0.0073 (16)0.697 (2)0.035*
O11.1926 (3)0.34767 (9)0.46237 (15)0.0295 (5)
O21.0579 (3)0.43564 (9)0.51720 (17)0.0358 (5)
O30.8438 (3)0.45907 (9)0.63801 (17)0.0376 (6)
O40.7109 (3)0.40657 (10)0.75400 (16)0.0330 (5)
O1W1.1046 (3)0.21633 (13)0.36503 (16)0.0390 (6)
H1WA0.990 (2)0.2183 (19)0.356 (3)0.058*
H1WB1.139 (4)0.1901 (16)0.326 (2)0.058*
H3A0.940 (5)0.4481 (18)0.574 (3)0.058*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0225 (14)0.0126 (13)0.0219 (14)0.0016 (11)0.0061 (11)0.0013 (10)
C20.0237 (14)0.0142 (13)0.0208 (14)0.0007 (10)0.0061 (11)0.0008 (10)
C30.0203 (13)0.0141 (13)0.0197 (13)0.0001 (10)0.0048 (10)0.0018 (10)
C40.0196 (14)0.0175 (14)0.0207 (14)0.0002 (11)0.0019 (10)0.0022 (11)
C50.0315 (15)0.0212 (15)0.0262 (15)0.0021 (12)0.0106 (12)0.0008 (11)
C60.0450 (18)0.0211 (15)0.0357 (18)0.0007 (13)0.0136 (14)0.0048 (13)
C70.0337 (17)0.0229 (15)0.0304 (16)0.0024 (12)0.0127 (13)0.0049 (12)
C80.0307 (15)0.0193 (14)0.0285 (15)0.0002 (12)0.0124 (12)0.0002 (12)
C90.0269 (15)0.0187 (14)0.0259 (15)0.0008 (11)0.0081 (12)0.0029 (11)
C100.0260 (15)0.0192 (14)0.0280 (16)0.0015 (12)0.0076 (12)0.0032 (11)
Co10.0246 (3)0.0161 (3)0.0218 (3)0.0021 (2)0.0090 (2)0.0006 (2)
N10.0215 (11)0.0137 (11)0.0187 (11)0.0008 (9)0.0065 (9)0.0009 (8)
N20.0229 (12)0.0159 (11)0.0235 (12)0.0006 (9)0.0079 (9)0.0007 (9)
N30.0361 (14)0.0144 (12)0.0375 (15)0.0041 (11)0.0083 (11)0.0038 (11)
O10.0361 (12)0.0200 (10)0.0365 (12)0.0046 (9)0.0201 (9)0.0075 (9)
O20.0500 (14)0.0132 (10)0.0498 (14)0.0029 (9)0.0275 (11)0.0058 (9)
O30.0600 (15)0.0148 (10)0.0439 (13)0.0026 (10)0.0285 (11)0.0002 (9)
O40.0425 (13)0.0223 (11)0.0383 (12)0.0023 (9)0.0211 (10)0.0056 (9)
O1W0.0258 (11)0.0621 (17)0.0296 (12)0.0044 (11)0.0056 (10)0.0179 (11)
Geometric parameters (Å, º) top
C1—N11.359 (3)C8—H80.9300
C1—C21.393 (4)C9—O11.248 (3)
C1—C91.475 (4)C9—O21.269 (3)
C2—N21.354 (3)C10—O41.237 (3)
C2—C101.479 (4)C10—O31.285 (3)
C3—N21.350 (3)Co1—O1i2.0659 (19)
C3—N11.355 (3)Co1—O12.0659 (19)
C3—C41.458 (3)Co1—O1Wi2.092 (2)
C4—C81.398 (4)Co1—O1W2.092 (2)
C4—C51.400 (4)Co1—N1i2.169 (2)
C5—C61.365 (4)Co1—N12.169 (2)
C5—H50.9300N3—H30.91 (3)
C6—N31.335 (4)O2—H3A1.25 (4)
C6—H60.9300O3—H3A1.20 (4)
C7—N31.332 (4)O1W—H1WA0.841 (18)
C7—C81.364 (4)O1W—H1WB0.810 (18)
C7—H70.9300
N1—C1—C2109.0 (2)O3—C10—C2117.5 (2)
N1—C1—C9119.0 (2)O1i—Co1—O1180.00 (11)
C2—C1—C9132.0 (2)O1i—Co1—O1Wi91.89 (9)
N2—C2—C1108.8 (2)O1—Co1—O1Wi88.11 (9)
N2—C2—C10121.5 (2)O1i—Co1—O1W88.11 (9)
C1—C2—C10129.6 (2)O1—Co1—O1W91.89 (9)
N2—C3—N1114.1 (2)O1Wi—Co1—O1W180.0
N2—C3—C4120.3 (2)O1i—Co1—N1i79.89 (7)
N1—C3—C4125.6 (2)O1—Co1—N1i100.11 (7)
C8—C4—C5117.5 (2)O1Wi—Co1—N1i90.55 (8)
C8—C4—C3119.3 (2)O1W—Co1—N1i89.45 (8)
C5—C4—C3123.2 (2)O1i—Co1—N1100.11 (7)
C6—C5—C4119.2 (3)O1—Co1—N179.89 (7)
C6—C5—H5120.4O1Wi—Co1—N189.45 (8)
C4—C5—H5120.4O1W—Co1—N190.55 (8)
N3—C6—C5121.5 (3)N1i—Co1—N1180.0
N3—C6—H6119.2C3—N1—C1103.8 (2)
C5—C6—H6119.2C3—N1—Co1147.82 (17)
N3—C7—C8120.7 (3)C1—N1—Co1104.92 (16)
N3—C7—H7119.7C3—N2—C2104.3 (2)
C8—C7—H7119.7C7—N3—C6120.8 (3)
C7—C8—C4120.2 (3)C7—N3—H3118 (2)
C7—C8—H8119.9C6—N3—H3121 (2)
C4—C8—H8119.9C9—O1—Co1113.00 (17)
O1—C9—O2122.6 (2)C9—O2—H3A109.5 (17)
O1—C9—C1117.9 (2)C10—O3—H3A112.3 (17)
O2—C9—C1119.6 (2)Co1—O1W—H1WA121 (2)
O4—C10—O3122.5 (2)Co1—O1W—H1WB127 (2)
O4—C10—C2120.0 (2)H1WA—O1W—H1WB109 (3)
Symmetry code: (i) x+5/2, y+1/2, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1WA···N2ii0.84 (2)2.05 (2)2.889 (3)176 (4)
O1W—H1WB···O4iii0.81 (2)2.27 (2)3.046 (3)161 (4)
N3—H3···O4iv0.91 (3)1.86 (3)2.754 (3)170 (3)
O3—H3A···O21.20 (4)1.25 (4)2.451 (3)172 (3)
Symmetry codes: (ii) x+3/2, y+1/2, z+1; (iii) x+1/2, y+1/2, z1/2; (iv) x+3/2, y1/2, z+3/2.

Experimental details

Crystal data
Chemical formula[Co(C10H6N3O4)2(H2O)2]
Mr559.32
Crystal system, space groupMonoclinic, C2/c
Temperature (K)296
a, b, c (Å)7.4146 (17), 20.190 (5), 13.361 (3)
β (°) 97.383 (3)
V3)1983.6 (8)
Z4
Radiation typeMo Kα
µ (mm1)0.95
Crystal size (mm)0.27 × 0.26 × 0.24
Data collection
DiffractometerBruker AXS SMART APEX CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.775, 0.797
No. of measured, independent and
observed [I > 2σ(I)] reflections
4997, 1775, 1480
Rint0.032
(sin θ/λ)max1)0.599
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.035, 0.088, 1.01
No. of reflections1775
No. of parameters181
No. of restraints3
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.27, 0.43

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1WA···N2i0.841 (18)2.050 (19)2.889 (3)176 (4)
O1W—H1WB···O4ii0.810 (18)2.27 (2)3.046 (3)161 (4)
N3—H3···O4iii0.91 (3)1.86 (3)2.754 (3)170 (3)
O3—H3A···O21.20 (4)1.25 (4)2.451 (3)172 (3)
Symmetry codes: (i) x+3/2, y+1/2, z+1; (ii) x+1/2, y+1/2, z1/2; (iii) x+3/2, y1/2, z+3/2.
 

Acknowledgements

The authors acknowledge South China Normal University and the National Natural Science Foundation of China (grant No. 20871048) for supporting this work.

References

First citationBruker (2004). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationChen, L. Z., Huang, Y., Xiong, R. & Hu, H. J. (2010). J. Mol. Struct. 963, 16–21.  Google Scholar
First citationLi, X., Liu, W., Wu, B.-L. & Zhang, H.-Y. (2009). Acta Cryst. E65, m820–m821.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationLi, X., Wu, B., Niu, C., Niu, Y. & Zhang, H. (2009). Cryst. Growth Des. 9, 3423–3431.  Web of Science CSD CrossRef CAS Google Scholar
First citationLiu, Z., Chen, Y., Liu, P., Wang, J. & Huang, M. H. (2005). J. Solid State Chem. 178, 2306–2312.  CrossRef CAS Google Scholar
First citationPeng, G., Qiu, Y. C., Liu, Z. H., Liu, B. & Deng, H. (2010). Cryst. Growth Des. 10, 114–121.  Web of Science CSD CrossRef CAS Google Scholar
First citationSheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSun, T., Ma, J.-P., Huang, R.-Q. & Dong, Y.-B. (2006). Acta Cryst. E62, o2751–o2752.  Web of Science CSD CrossRef IUCr Journals Google Scholar

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