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The title polymeric complex, [Co(μ-C4H2O4)(C7H6N2)2(H2O)2]n, displays a one-dimensional chain structure bridged by fumarate dianions. In the crystal structure, the polymeric chains are linked to each other by hydrogen bonds. The overlapped arrangement and the short separation of 3.35 (2) Å suggest the existence of π–π stacking between parallel benz­imidazole rings. The CoII atom exists in a centrosymmetric octahedral geometry.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803017586/lh6099sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803017586/lh6099Isup2.hkl
Contains datablock I

CCDC reference: 222809

Key indicators

  • Single-crystal X-ray study
  • T = 150 K
  • Mean [sigma](C-C) = 0.008 Å
  • R factor = 0.045
  • wR factor = 0.113
  • Data-to-parameter ratio = 12.2

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ..... 0.99 PLAT341_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang.. 8
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 2 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 2 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion

Comment top

The aromatic ππ-stacking interaction has shown to be correlated with the electron transfer in some biological system (Deisenhofer & Michel, 1989). As part of investigation on the ππ-stacking interaction in metal complexes (Chen, 2003), the title polymeric CoII complex, (I), with the benzimidazole ligand has recently been prepared in the laboratory.

The coordination environment around the CoII atom in (I) is illustrated in Fig. 1. The CoII atom is located at an inversion center and possesses an octahedral coordinate geometry formed by benzimidazole molecules, water molecules and fumarate dianions with the normal geometry parameters (Table 1). The carboxyl group of the fumarate dianion coordinates in a monodentate manner to the CoII atom. The uncoordinated carboxyl O atom (O2) is hydrogen bonded to the neighboring benzimidazole and coordinated water molecules (Fig. 1).

Each fumarate dianion bridges two CoII atoms through both terminal carboxyl groups to form polymeric complex chains as shown in Fig. 2. Adjacent polymeric chains link each other by hydrogen bonds (Table 2). The overlapped arrangement of benzimidazole rings is observed between the adjacent complex molecules related by an inversion center (Fig. 3). The shorter separation of 3.35 (2) Å between neighboring parallel benzimidazole rings suggests the existence of the ππ stacking.

Experimental top

An ethanol solution (5 ml) of benzimidazole (0.24 g, 2 mmol) was mixed with an aqueous solution (5 ml) of CoCl2·6H2O (0.24 g, 1 mmol) at room temperature. After refluxing the solution for 30 min, an aqueous solution (5 ml) containing fumaric acid (0.12 g, 1 mmol) and NaOH (0.08 g, 2 mmol) was added. The mixture was refluxed for 1 h and filtered. The pink single crystals were obtained after 2 d.

Refinement top

H atoms of the water molecule were located in a difference Fourier map and were included in structure-factor calculations with fixed positional and displacement parameters of Uiso = 0.05 Å2. Other H atoms were placed in calculated positions with C—H distances of 0.93 Å and N—H distances of 0.86 Å, and were included in final cycles of refinement in the riding mode with Uiso(H) = 1.2Ueq of the carrier atom.

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and XP (Siemens, 1994); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The coordination environment around the CoII atom in (I), with 50% probability displacement ellipsoids. Dashed lines indicate the hydrogen bonding [symmetry codes: (i)-x, −y, 1 − z; (ii) 1 − x, 1 − y, 2 − z; (iii) −x, 1 − y, 1 − z; (iv) 1 − x, 1 − y, 1 − z].
[Figure 2] Fig. 2. The molecular packing diagram, dashed lines indicate the hydrogen bonging between adjacent polymeric chains.
[Figure 3] Fig. 3. A diagram showing the ππ stacking between neighboring benzimidazole rings [symmetry code: (v) 2 − x, 1 − y, 2 − z].
(I) top
Crystal data top
[Co(C4H2O4)(C7H6N2)2(H2O)2]Z = 1
Mr = 445.29F(000) = 229
Triclinic, P1Dx = 1.625 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.0668 (10) ÅCell parameters from 1988 reflections
b = 8.5150 (12) Åθ = 2.0–23.0°
c = 8.7929 (13) ŵ = 0.99 mm1
α = 99.358 (11)°T = 150 K
β = 113.322 (13)°Prism, pink
γ = 102.787 (12)°0.32 × 0.30 × 0.22 mm
V = 454.95 (13) Å3
Data collection top
Bruker SMART CCD
diffractometer
1623 independent reflections
Radiation source: fine-focus sealed tube996 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.053
ω and ϕ scansθmax = 25.2°, θmin = 2.6°
Absorption correction: empirical (using intensity measurements)
(SADABS; Bruker, 1999)
h = 84
Tmin = 0.722, Tmax = 0.802k = 910
2497 measured reflectionsl = 1010
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)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.113H-atom parameters constrained
S = 0.91 w = 1/[σ2(Fo2) + (0.0269P)2 + 0.2058P]
where P = (Fo2 + 2Fc2)/3
1623 reflections(Δ/σ)max < 0.001
133 parametersΔρmax = 0.51 e Å3
0 restraintsΔρmin = 0.50 e Å3
Crystal data top
[Co(C4H2O4)(C7H6N2)2(H2O)2]γ = 102.787 (12)°
Mr = 445.29V = 454.95 (13) Å3
Triclinic, P1Z = 1
a = 7.0668 (10) ÅMo Kα radiation
b = 8.5150 (12) ŵ = 0.99 mm1
c = 8.7929 (13) ÅT = 150 K
α = 99.358 (11)°0.32 × 0.30 × 0.22 mm
β = 113.322 (13)°
Data collection top
Bruker SMART CCD
diffractometer
1623 independent reflections
Absorption correction: empirical (using intensity measurements)
(SADABS; Bruker, 1999)
996 reflections with I > 2σ(I)
Tmin = 0.722, Tmax = 0.802Rint = 0.053
2497 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.113H-atom parameters constrained
S = 0.91Δρmax = 0.51 e Å3
1623 reflectionsΔρmin = 0.50 e Å3
133 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
Co0.50000.50000.50000.0168 (3)
O10.2738 (5)0.2672 (4)0.4332 (4)0.0183 (9)
O20.1069 (5)0.3189 (4)0.5978 (4)0.0173 (8)
O30.2983 (5)0.6180 (4)0.5682 (4)0.0194 (9)
N10.7701 (6)0.5607 (5)1.0466 (5)0.0190 (10)
H10.81580.62301.14930.023*
N30.6309 (6)0.4838 (5)0.7561 (5)0.0179 (10)
C20.6941 (8)0.6059 (6)0.8993 (6)0.0201 (13)
H20.68620.71320.89740.024*
C40.6366 (8)0.1839 (6)0.7264 (6)0.0204 (13)
H40.57860.15050.60680.025*
C50.6938 (9)0.0747 (7)0.8255 (7)0.0269 (14)
H50.67120.03520.76970.032*
C60.7858 (8)0.1247 (7)1.0094 (6)0.0277 (14)
H60.82560.04851.07060.033*
C70.8158 (8)0.2843 (7)1.0963 (7)0.0247 (13)
H70.87170.31701.21580.030*
C80.7606 (7)0.3943 (6)1.0008 (6)0.0176 (12)
C90.6715 (8)0.3471 (6)0.8175 (6)0.0161 (12)
C110.1553 (8)0.2211 (6)0.5030 (6)0.0169 (12)
C120.0596 (8)0.0350 (6)0.4656 (6)0.0207 (13)
H120.08620.03500.38890.025*
H310.22500.52560.60030.050*
H320.18290.64750.50390.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co0.0184 (6)0.0157 (6)0.0172 (6)0.0054 (5)0.0089 (5)0.0045 (5)
O10.022 (2)0.017 (2)0.0192 (19)0.0031 (16)0.0141 (17)0.0045 (16)
O20.024 (2)0.012 (2)0.022 (2)0.0062 (16)0.0152 (17)0.0050 (16)
O30.017 (2)0.021 (2)0.025 (2)0.0078 (16)0.0107 (17)0.0097 (17)
N10.025 (3)0.018 (3)0.011 (2)0.007 (2)0.007 (2)0.001 (2)
N30.022 (2)0.016 (3)0.021 (2)0.007 (2)0.014 (2)0.007 (2)
C20.029 (3)0.012 (3)0.020 (3)0.006 (2)0.013 (3)0.004 (2)
C40.028 (3)0.018 (3)0.018 (3)0.006 (2)0.012 (3)0.006 (2)
C50.042 (4)0.017 (3)0.032 (3)0.013 (3)0.024 (3)0.010 (3)
C60.035 (4)0.032 (4)0.022 (3)0.020 (3)0.011 (3)0.016 (3)
C70.025 (3)0.032 (4)0.017 (3)0.014 (3)0.007 (3)0.008 (3)
C80.014 (3)0.020 (3)0.016 (3)0.003 (2)0.007 (2)0.001 (3)
C90.019 (3)0.018 (3)0.018 (3)0.006 (2)0.012 (2)0.010 (2)
C110.018 (3)0.019 (3)0.014 (3)0.007 (2)0.006 (2)0.007 (2)
C120.029 (3)0.015 (3)0.026 (3)0.008 (2)0.021 (3)0.003 (2)
Geometric parameters (Å, º) top
Co—O12.075 (3)C4—C51.392 (7)
Co—N32.110 (4)C4—C91.402 (7)
Co—O32.125 (3)C4—H40.93
O1—C111.253 (5)C5—C61.428 (7)
O2—C111.278 (5)C5—H50.93
O3—H310.987C6—C71.372 (7)
O3—H320.905C6—H60.93
N1—C21.348 (6)C7—C81.375 (7)
N1—C81.387 (6)C7—H70.93
N1—H10.86C8—C91.425 (6)
N3—C21.338 (6)C11—C121.502 (7)
N3—C91.399 (6)C12—C12i1.315 (8)
C2—H20.93C12—H120.93
O1—Co—N387.60 (13)C4—C5—H5118.7
O1—Co—O389.97 (12)C6—C5—H5118.7
N3—Co—O385.64 (14)C7—C6—C5120.5 (5)
C11—O1—Co128.1 (3)C7—C6—H6119.8
Co—O3—H3198.1C5—C6—H6119.8
Co—O3—H32131.6C6—C7—C8117.8 (5)
H31—O3—H32100.1C6—C7—H7121.1
C2—N1—C8106.9 (4)C8—C7—H7121.1
C2—N1—H1126.5C7—C8—N1132.4 (5)
C8—N1—H1126.5C7—C8—C9122.4 (5)
C2—N3—C9103.7 (4)N1—C8—C9105.1 (4)
C2—N3—Co126.9 (3)N3—C9—C4129.7 (5)
C9—N3—Co129.4 (3)N3—C9—C8109.7 (4)
N3—C2—N1114.5 (5)C4—C9—C8120.6 (5)
N3—C2—H2122.8O1—C11—O2125.3 (5)
N1—C2—H2122.8O1—C11—C12116.0 (4)
C5—C4—C9116.0 (5)O2—C11—C12118.6 (4)
C5—C4—H4122.0C12i—C12—C11124.1 (6)
C9—C4—H4122.0C12i—C12—H12117.9
C4—C5—C6122.7 (5)C11—C12—H12117.9
Symmetry code: (i) x, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H31···O20.991.772.712 (5)159
O3—H32···O2ii0.911.992.871 (5)163
N1—H1···O2iii0.862.012.827 (5)158
Symmetry codes: (ii) x, y+1, z+1; (iii) x+1, y+1, z+2.

Experimental details

Crystal data
Chemical formula[Co(C4H2O4)(C7H6N2)2(H2O)2]
Mr445.29
Crystal system, space groupTriclinic, P1
Temperature (K)150
a, b, c (Å)7.0668 (10), 8.5150 (12), 8.7929 (13)
α, β, γ (°)99.358 (11), 113.322 (13), 102.787 (12)
V3)454.95 (13)
Z1
Radiation typeMo Kα
µ (mm1)0.99
Crystal size (mm)0.32 × 0.30 × 0.22
Data collection
DiffractometerBruker SMART CCD
diffractometer
Absorption correctionEmpirical (using intensity measurements)
(SADABS; Bruker, 1999)
Tmin, Tmax0.722, 0.802
No. of measured, independent and
observed [I > 2σ(I)] reflections
2497, 1623, 996
Rint0.053
(sin θ/λ)max1)0.599
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.113, 0.91
No. of reflections1623
No. of parameters133
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.51, 0.50

Computer programs: SMART (Bruker, 1999), SAINT (Bruker, 1999), SAINT, SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997) and XP (Siemens, 1994), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
Co—O12.075 (3)O2—C111.278 (5)
Co—N32.110 (4)C11—C121.502 (7)
Co—O32.125 (3)C12—C12i1.315 (8)
O1—C111.253 (5)
O1—Co—N387.60 (13)N3—Co—O385.64 (14)
O1—Co—O389.97 (12)
Symmetry code: (i) x, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H31···O20.991.772.712 (5)159
O3—H32···O2ii0.911.992.871 (5)163
N1—H1···O2iii0.862.012.827 (5)158
Symmetry codes: (ii) x, y+1, z+1; (iii) x+1, y+1, z+2.
 

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