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The title compound, [Cd(C4H4O4)(C7H6N2)2(H2O)]n, is a three-dimensional polymeric complex. The CdII atom is located on an inversion centre and assumes an elongated octahedral coordination geometry, with a long Cd-O distance of 2.5381 (5) Å to the coordinated bridging water molecule. The succinate dianion, located on another inversion centre, bridges adjacent Cd atoms to form succinate-bridged polymeric chains. The coordinated water mol­ecule is located on a twofold axis and links adjacent succinate-bridged chains to form a water-bridged polymeric chain.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103027847/ob1153sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103027847/ob1153Isup2.hkl
Contains datablock I

CCDC reference: 233099

Comment top

In carboxylate-bridging metal complexes, a variety of bridging modes, such as µ2, µ3 and µ4 bridges, have been found (Ng, 1998; Rastsvetaeva et al., 1996; Ng & Kumar Das, 1993). Some recent structure determinations have shown that the coordination mode of the carboxylate anion is related to the hydrogen bonding between carboxylate and imidazole ligands (Liu et al., 2003). In order to study the effect of this hydrogen bonding between carboxylate and neighbouring ligands on the coordination mode of the carboxylate, a series of metal complexes with both dicarboxylate and benzimidazole ligands has been prepared in this laboratory. The title compound, (I), is one of these and its crystal stucture is presented here. \sch

The structure of (I) is shown in Fig. 1. This CdII complex is polymeric, and the repeat unit contains a CdII atom, a water molecule, a succinate dianion and two benzimidazole molecules. The Cd atom is located on an inversion centre. The coordination geometry is an elongated octahedron, formed by succinate dianions, benzimidazole ligands and water molecules, with a normal Cd—O1 bond length of 2.2421 (13) Å and a longer Cd—O3 bond distance (discussed below).

The succinate dianion is located on an inversion centre. The planar carbon skeleton is approximately perpendicular to the carboxyl group, with a dihedral angle of 78.56 (17)°. Each succinate dianion bridges two adjacent Cd atoms via both terminal carboxyl groups, to form the succinate-bridged polymeric chain shown in Fig. 1. The carboxyl group coordinates to the Cd atom in a monodentate mode, and the uncoordinated carboxyl atom O2 is hydrogen-bonded to the neighbouring coordinated water molecule (Fig. 1) and benzimidazole ligand (Fig. 2 and Table 2).

The coordinated water atom O3 is located on a twofold axis and links adjacent succinate-bridged chains to form water-bridged polymeric chains along the [001] direction (Fig. 2). Two succinate-bridged chains linked by the water molecule extend along the [110] and [110] directions, respectively, separated by 4.8912 (10) Å, a half of the c length. Thus, these polymeric chains are nearly perpendicular to each other and form the three-dimensional polymeric structure (Fig. 3). O—H.·O and N—H.·O hydrogen bonds (Table 2) stabilize the three-dimensional polymeric structure of (I).

The Cd—O3 bond distance of 2.5381 (5) Å is significantly longer than the Cd—O(water) bonds found in analogous reported structures, for example 2.373 (3) Å in aqua-nicotinato-cadmium(II) (Zhang et al., 1996) and 2.364–2.279 Å in diaqua-succinato-cadmium(II) (Griffith et al., 1982). However, it is comparable with the Cd—O(µ2-H2O) bond distances found in some µ2-aqua-cadmium(II) complexes, for example 2.537 Å in catena[bis(µ2-aqua)-hexakis(µ2-cyano)-aqua-di-cadmium(II)-di-copper(I)] (Nishikiori, 1996) and 2.619 Å in bis(µ2-aqua)bis[triaqua(µ2-phenylenediamine-tetraacetato)dicadmium(II)] (Nakasuka et al., 1986). The Cd—O3—Cdii bond angle in (I) is 148.96 (8)°, which is much larger than the values of 113.8 and 104.8°, respectively, in the µ2-aqua-cadmium(II) complexes cited above [symmetry code: (ii) 1 − x, y, 1/2 − z]. However, the Cd—O(µ2-H2O) bond distances are essentially the same in these complexes. This fact may suggest an electrostatic bonding interaction between the Cd atom and the bridging water molecule.

The benzimidazole ligand displays normal geometry in (I). A ππ stacking interaction is usually found in the structures of metal complexes with benzimidazole ligands, but no ππ stacking between the benzimidazole rings was observed in the present three-dimensional polymeric structure.

Experimental top

CdCl2·2H2O (0.11 g, 0.5 mmol) was added to an aqueous solution (20 ml) containing succinic acid (0.06 g, 0.5 mmol) and NaOH (0.04 g, 1 mmol). After refluxing the mixture for 1 h, an aqueous solution (10 ml) of benzimidazole (0.12 g, 1 mmol) was added. The solution was refluxed for 3 h and filtered. After cooling to room temperature, the solution was filtered once more. Single crystals of (I) were obtained from the filtrate after 40 d.

Refinement top

H atoms on methylene and that of the water molecule were located in difference Fourier maps and included in the structure factor calculations in fixed positions, with Uiso(H) = 0.05 Å2. The H atoms of the benzimidazole ligand were placed in calculated positions, with C—H = 0.93 and N—H = 0.86 Å, and included in the final cycles of refinement using a riding model, with Uiso(H) = 1.2Ueq of the carrier atom.

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Molecular Structure Corporation and Rigaku, 2002); 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); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level [symmetry codes: (i) 1/2 − x, 1/2 − y, 1 − z; (iv) 1 − x, −y, 1 − z].
[Figure 2] Fig. 2. Illustration of the coordinated water atom O3 linking neighbouring succinate-bridged chains of complex (I) [symmetry code: (ii) 1 − x, y, 1/2 − z].
[Figure 3] Fig. 3. The molecular packing in (I), showing the succinate-bridged chains extending along different directions. Bonds involving the coordinated water atom (O3) have been omitted for clarity.
Poly[[bis(1H-benzimidazole-κN3)cadmium(II)]-µ-aqua-µ- succinato-κ2O1:O4] top
Crystal data top
[Cd(C4H4O4)(C7H6N2)2(H2O)]F(000) = 968
Mr = 482.76Dx = 1.788 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 6608 reflections
a = 13.1406 (11) Åθ = 2.8–26.0°
b = 14.0664 (12) ŵ = 1.26 mm1
c = 9.7823 (10) ÅT = 295 K
β = 97.415 (19)°Prism, colourless
V = 1793.0 (3) Å30.32 × 0.24 × 0.16 mm
Z = 4
Data collection top
Rigaku R-AXIS RAPID
diffractometer
2061 independent reflections
Radiation source: fine-focus sealed tube1922 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.015
Detector resolution: 10.00 pixels mm-1θmax = 27.5°, θmin = 2.1°
ω scansh = 1717
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
k = 1818
Tmin = 0.660, Tmax = 0.818l = 1212
8568 measured reflections
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)] = 0.023H-atom parameters constrained
wR(F2) = 0.072 w = 1/[σ2(Fo2) + (0.041P)2 + 0.6321P]
where P = (Fo2 + 2Fc2)/3
S = 1.34(Δ/σ)max = 0.002
2061 reflectionsΔρmax = 0.64 e Å3
130 parametersΔρmin = 0.56 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0097 (6)
Crystal data top
[Cd(C4H4O4)(C7H6N2)2(H2O)]V = 1793.0 (3) Å3
Mr = 482.76Z = 4
Monoclinic, C2/cMo Kα radiation
a = 13.1406 (11) ŵ = 1.26 mm1
b = 14.0664 (12) ÅT = 295 K
c = 9.7823 (10) Å0.32 × 0.24 × 0.16 mm
β = 97.415 (19)°
Data collection top
Rigaku R-AXIS RAPID
diffractometer
2061 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
1922 reflections with I > 2σ(I)
Tmin = 0.660, Tmax = 0.818Rint = 0.015
8568 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0230 restraints
wR(F2) = 0.072H-atom parameters constrained
S = 1.34Δρmax = 0.64 e Å3
2061 reflectionsΔρmin = 0.56 e Å3
130 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
Cd0.50000.00000.50000.02326 (11)
O10.41795 (10)0.13344 (9)0.54720 (13)0.0325 (3)
O20.36730 (12)0.17604 (12)0.32953 (15)0.0401 (4)
O30.50000.04827 (13)0.25000.0260 (4)
N10.75909 (13)0.18721 (12)0.66107 (16)0.0353 (4)
H10.78290.23010.71920.042*
N30.64934 (11)0.08462 (11)0.55024 (15)0.0288 (3)
C20.66391 (16)0.15018 (16)0.6472 (2)0.0323 (4)
H20.61370.16880.70040.039*
C40.77069 (17)0.02604 (18)0.3868 (3)0.0382 (4)
H40.72520.01650.33850.046*
C50.86832 (19)0.0381 (2)0.3535 (3)0.0522 (6)
H50.88890.00330.28110.063*
C60.93754 (18)0.1017 (2)0.4260 (3)0.0540 (6)
H61.00320.10760.40110.065*
C70.91057 (16)0.15537 (17)0.5330 (2)0.0451 (5)
H70.95650.19740.58150.054*
C80.81125 (14)0.14387 (14)0.56519 (19)0.0317 (4)
C90.74218 (13)0.07969 (13)0.49521 (19)0.0281 (4)
C100.37000 (13)0.18563 (12)0.45745 (19)0.0254 (4)
C110.30641 (13)0.26530 (13)0.50791 (19)0.0272 (4)
H30.45280.09070.26410.050*
H11A0.31540.32220.45850.050*
H11B0.32910.28050.59530.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cd0.01888 (14)0.02134 (15)0.02911 (15)0.00152 (5)0.00142 (8)0.00038 (5)
O10.0324 (7)0.0298 (7)0.0353 (7)0.0115 (5)0.0046 (5)0.0036 (6)
O20.0446 (9)0.0444 (9)0.0321 (7)0.0204 (7)0.0078 (6)0.0018 (6)
O30.0246 (8)0.0263 (9)0.0274 (8)0.0000.0041 (7)0.000
N10.0384 (9)0.0352 (9)0.0312 (8)0.0114 (7)0.0002 (7)0.0057 (7)
N30.0252 (7)0.0302 (8)0.0302 (7)0.0037 (6)0.0010 (6)0.0015 (6)
C20.0334 (10)0.0342 (10)0.0292 (9)0.0057 (8)0.0037 (8)0.0019 (8)
C40.0329 (11)0.0364 (10)0.0450 (11)0.0023 (10)0.0035 (9)0.0085 (11)
C50.0421 (13)0.0580 (16)0.0602 (15)0.0013 (12)0.0203 (11)0.0122 (13)
C60.0326 (11)0.0623 (16)0.0696 (16)0.0079 (11)0.0162 (11)0.0034 (13)
C70.0297 (10)0.0476 (13)0.0569 (13)0.0148 (9)0.0013 (9)0.0014 (11)
C80.0303 (9)0.0320 (9)0.0314 (9)0.0056 (7)0.0018 (7)0.0025 (7)
C90.0228 (8)0.0282 (9)0.0324 (8)0.0024 (7)0.0004 (7)0.0023 (7)
C100.0194 (7)0.0233 (8)0.0343 (9)0.0023 (6)0.0062 (7)0.0014 (7)
C110.0247 (8)0.0239 (9)0.0334 (8)0.0048 (7)0.0050 (7)0.0006 (7)
Geometric parameters (Å, º) top
Cd—O12.2421 (13)C4—C91.392 (3)
Cd—N32.2936 (15)C4—H40.9300
Cd—O32.5381 (5)C5—C61.401 (4)
O1—C101.251 (2)C5—H50.9300
O2—C101.255 (2)C6—C71.374 (4)
O3—H30.884C6—H60.9300
N1—C21.345 (3)C7—C81.391 (3)
N1—C81.374 (3)C7—H70.9300
N1—H10.8600C8—C91.395 (3)
N3—C21.319 (3)C10—C111.518 (2)
N3—C91.397 (2)C11—C11i1.532 (3)
C2—H20.9300C11—H11A0.950
C4—C51.374 (3)C11—H11B0.894
O1—Cd—N386.69 (5)C7—C6—C5121.5 (2)
O1—Cd—O391.96 (5)C7—C6—H6119.3
N3—Cd—O387.78 (5)C5—C6—H6119.3
C10—O1—Cd123.99 (12)C6—C7—C8116.8 (2)
Cdii—O3—Cd148.96 (8)C6—C7—H7121.6
Cdii—O3—H3114.7C8—C7—H7121.6
Cd—O3—H386.7N1—C8—C7131.95 (19)
C2—N1—C8107.38 (16)N1—C8—C9105.77 (16)
C2—N1—H1126.3C7—C8—C9122.28 (19)
C8—N1—H1126.3C4—C9—C8120.17 (18)
C2—N3—C9105.00 (15)C4—C9—N3130.90 (17)
C2—N3—Cd123.89 (13)C8—C9—N3108.89 (16)
C9—N3—Cd131.08 (12)O1—C10—O2125.72 (16)
N3—C2—N1112.94 (18)O1—C10—C11116.99 (16)
N3—C2—H2123.5O2—C10—C11117.25 (16)
N1—C2—H2123.5C10—C11—C11i109.02 (18)
C5—C4—C9117.7 (2)C10—C11—H11A110.3
C5—C4—H4121.2C11i—C11—H11A111.6
C9—C4—H4121.2C10—C11—H11B111.0
C4—C5—C6121.6 (2)C11i—C11—H11B111.3
C4—C5—H5119.2H11A—C11—H11B103.7
C6—C5—H5119.2H3—O3—H3ii95.1
Symmetry codes: (i) x+1/2, y+1/2, z+1; (ii) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O2iii0.861.962.799 (2)166
O3—H3···O20.881.822.688 (2)168
Symmetry code: (iii) x+1/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula[Cd(C4H4O4)(C7H6N2)2(H2O)]
Mr482.76
Crystal system, space groupMonoclinic, C2/c
Temperature (K)295
a, b, c (Å)13.1406 (11), 14.0664 (12), 9.7823 (10)
β (°) 97.415 (19)
V3)1793.0 (3)
Z4
Radiation typeMo Kα
µ (mm1)1.26
Crystal size (mm)0.32 × 0.24 × 0.16
Data collection
DiffractometerRigaku R-AXIS RAPID
diffractometer
Absorption correctionMulti-scan
(ABSCOR; Higashi, 1995)
Tmin, Tmax0.660, 0.818
No. of measured, independent and
observed [I > 2σ(I)] reflections
8568, 2061, 1922
Rint0.015
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.023, 0.072, 1.34
No. of reflections2061
No. of parameters130
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.64, 0.56

Computer programs: PROCESS-AUTO (Rigaku, 1998), PROCESS-AUTO, CrystalStructure (Molecular Structure Corporation and Rigaku, 2002), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
Cd—O12.2421 (13)C10—C111.518 (2)
Cd—N32.2936 (15)C11—C11i1.532 (3)
Cd—O32.5381 (5)
O1—Cd—N386.69 (5)C10—O1—Cd123.99 (12)
O1—Cd—O391.96 (5)Cdii—O3—Cd148.96 (8)
N3—Cd—O387.78 (5)
Symmetry codes: (i) x+1/2, y+1/2, z+1; (ii) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O2iii0.861.962.799 (2)166
O3—H3···O20.881.822.688 (2)168
Symmetry code: (iii) x+1/2, y+1/2, z+1/2.
 

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