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Acta Crystallogr Sect E Struct Rep Online. 2009 September 1; 65(Pt 9): m1091.
Published online 2009 August 19. doi:  10.1107/S1600536809031766
PMCID: PMC2969862

Tetra­aqua­bis(2-methyl­benzimidazolium-1,3-diacetato-κO)zinc(II) tetra­hydrate

Abstract

The asymmetric unit of the title compound, [Zn(C12H11N2O4)2(H2O)4]·4H2O, contains one-half of the complex mol­ecule and two uncoordin­ated water mol­ecules. The four water O atoms in the equatorial plane around the ZnII centre (An external file that holds a picture, illustration, etc.
Object name is e-65-m1091-efi1.jpg symmetry) form a distorted square-planar arrangement, while the distorted octa­hedral coordination geometry is completed by the O atoms of the zwitterionic 2-methyl­benzimidazolium-1,3-diacetate ligands in the axial positions. The benzimidazole ring system is planar, with a maximum deviation of 0.041 (3) Å. Intra­molecular O—H(...)O hydrogen bonding results in the formation of a non-planar six-membered ring. In the crystal structure, strong intra- and inter­molecular O—H(...)O hydrogen bonds link the mol­ecules into a three-dimensional network. π–π contacts between benzimidazole rings [centroid–centroid distance = 3.899 (1) Å] may further stabilize the structure.

Related literature

For general background to metal-organic frameworks, see: Robson et al. (2000 [triangle]); Kitagawa et al. (2004 [triangle]). For a related structure, see: Ni et al. (2007 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-m1091-scheme1.jpg

Experimental

Crystal data

  • [Zn(C12H11N2O4)2(H2O)4]·4H2O
  • M r = 703.95
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-m1091-efi2.jpg
  • a = 7.2749 (9) Å
  • b = 21.265 (3) Å
  • c = 9.7794 (12) Å
  • β = 104.467 (2)°
  • V = 1464.9 (3) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.92 mm−1
  • T = 294 K
  • 0.32 × 0.21 × 0.15 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.757, T max = 0.874
  • 7436 measured reflections
  • 3202 independent reflections
  • 2582 reflections with I > 2σ(I)
  • R int = 0.022

Refinement

  • R[F 2 > 2σ(F 2)] = 0.036
  • wR(F 2) = 0.097
  • S = 1.10
  • 3202 reflections
  • 237 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.98 e Å−3
  • Δρmin = −0.51 e Å−3

Data collection: SMART (Bruker, 1998 [triangle]); cell refinement: SAINT (Bruker, 1998 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Selected geometric parameters (Å, °)
Table 2
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809031766/hk2732sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809031766/hk2732Isup2.hkl

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

Acknowledgments

This work was supported by the Natural Science Foundation of Guangxi Province (grant No. 0832100) and the Programme for Excellent Talents in Guangxi Higher Education Institutions.

supplementary crystallographic information

Comment

The quest to rational design and construct metal-organic frameworks (MOF) is highly topical, for their intriguing topologies and potential applications as functional materials in many areas such as catalysis, molecular adsorption, magnetism properties, non-linear optics and molecular sensing (Robson, 2000; Kitagawa et al., 2004). In order to explore further the influence of novel polycarboxylate ligand which is a good candidate as building block on MOFs, we developed a flexible ligand 1-acetoxy-2-methylbenzimidazole-3-acetate acid [HL] (Ni et al., 2007), to prepare the title mononuclear complex. We report herein its crystal structure.

The asymmetric unit of the title compound, (Fig. 1), contains one-half molecule, two coordinated and two uncoordinated water molecules. The Zn atom is surrounded by two 2-methylbenzimidazolium-1,3-diacetate and four water molecules. The four O atoms (O5, O6, O5A and O6A atoms) in the equatorial plane around the Zn atom form a distorted square-planar arrangement, while the distorted octahedral coordination is completed by the O atoms of the 2-methylbenzimidazolium-1,3-diacetate ligands (O4 and O4A) in the axial positions [symmetry code: (A) -x, -y, -z] (Table 1). The benzimidazole ring system is planar with a maximum deviation of 0.041 (3) Å for atom C7. Intramolecular O-H···O hydrogen bond results in the formation of a six-membered ring (Zn1/O3/O4/C6/C10/H6A) having twisted conformation.

In the crystal structure, strong intra- and intermolecular O-H···O hydrogen bonds (Table 2) link the molecules into a three-dimensional network, in which they may be effective in the stabilization of the structure. The π–π contact between the benzimidazole rings, Cg1—Cg2i [symmetry code: (i) 1/2 + x, 1/2 - y, 1/2 + z, where Cg1 and Cg2 are centroids of the rings A (N1/N2/C1/C6/C7) and B (C1-C6), respectively] may further stabilize the structure, with centroid-centroid distance of 3.899 (1) Å.

Experimental

After the pH of a mixture containing ZnCl2.2H2O (0.0408 g, 0.3 mmol) and ligand HL (0.0498 g, 0.2 mmol) was adjusted by ammonia to 7, the resulting solution was sealed in a Teflon-lined steel liner (25 ml) and then heated at 423 K for 3 d. Colorless block crystals were collected (yield; 28%).

Refinement

H atoms of water molecules were located in difference Fourier maps and refined isotropically. The remaining H atoms were positioned geometrically with C-H = 0.93, 0.97 and 0.96 Å, for aromatic, methylene and methyl H atoms, respectively, and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Figures

Fig. 1.
The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level [symmetry code: (A) -x, -y, -z].
Fig. 2.
A partial packing diagram. Hydrogen bonds are shown as dashed lines.

Crystal data

[Zn(C12H11N2O4)2(H2O)4]·4H2OF(000) = 736
Mr = 703.95Dx = 1.596 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 3729 reflections
a = 7.2749 (9) Åθ = 2.4–27.0°
b = 21.265 (3) ŵ = 0.92 mm1
c = 9.7794 (12) ÅT = 294 K
β = 104.467 (2)°Block, colorless
V = 1464.9 (3) Å30.32 × 0.21 × 0.15 mm
Z = 2

Data collection

Bruker SMART CCD area-detector diffractometer3202 independent reflections
Radiation source: fine-focus sealed tube2582 reflections with I > 2σ(I)
graphiteRint = 0.022
ω scansθmax = 27.1°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −8→9
Tmin = 0.757, Tmax = 0.874k = −14→27
7436 measured reflectionsl = −10→12

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.097H atoms treated by a mixture of independent and constrained refinement
S = 1.10w = 1/[σ2(Fo2) + (0.0541P)2 + 0.4211P] where P = (Fo2 + 2Fc2)/3
3202 reflections(Δ/σ)max < 0.001
237 parametersΔρmax = 0.98 e Å3
0 restraintsΔρmin = −0.51 e Å3

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
Zn10.00000.00000.00000.01544 (12)
O10.1738 (2)0.37790 (7)−0.04309 (16)0.0235 (4)
O20.3049 (2)0.44774 (7)0.12371 (16)0.0225 (4)
O30.1638 (2)0.13757 (7)−0.05157 (16)0.0203 (3)
O40.2586 (2)0.05044 (7)0.07499 (16)0.0190 (3)
O5−0.0725 (3)0.01888 (8)0.19098 (18)0.0210 (4)
H5A−0.012 (5)−0.0003 (15)0.242 (4)0.042 (11)*
H5B−0.180 (5)0.0100 (13)0.190 (3)0.030 (8)*
O6−0.1608 (2)0.07925 (7)−0.08958 (19)0.0201 (3)
H6A−0.054 (5)0.1041 (17)−0.080 (4)0.065 (11)*
H6B−0.191 (4)0.0718 (15)−0.167 (3)0.038 (9)*
O7−0.8479 (3)0.55949 (9)−0.00644 (19)0.0270 (4)
H7A−0.940 (6)0.5704 (19)0.012 (3)0.060 (12)*
H7B−0.814 (5)0.5299 (17)0.040 (3)0.041 (9)*
O8−0.4182 (3)−0.02154 (9)0.2126 (2)0.0255 (4)
H8A−0.505 (5)−0.0026 (12)0.179 (3)0.021 (7)*
H8B−0.409 (4)−0.0284 (15)0.294 (3)0.036 (9)*
N10.4887 (2)0.29835 (8)0.03733 (19)0.0149 (4)
N20.4950 (2)0.19548 (8)0.03276 (18)0.0145 (4)
C10.4865 (3)0.28122 (10)−0.1007 (2)0.0157 (4)
C20.4759 (3)0.31727 (10)−0.2218 (2)0.0197 (5)
H2A0.47530.3610−0.21990.024*
C30.4664 (3)0.28382 (11)−0.3447 (2)0.0230 (5)
H3A0.45990.3059−0.42790.028*
C40.4661 (3)0.21788 (11)−0.3484 (2)0.0225 (5)
H4A0.45670.1976−0.43410.027*
C50.4795 (3)0.18208 (10)−0.2272 (2)0.0194 (5)
H5C0.48110.1384−0.22860.023*
C60.4903 (3)0.21592 (10)−0.1039 (2)0.0152 (4)
C70.4906 (3)0.24587 (9)0.1143 (2)0.0147 (4)
C80.4841 (3)0.24357 (10)0.2639 (2)0.0198 (5)
H8C0.48160.28560.29920.030*
H8D0.59440.22210.31810.030*
H8E0.37200.22150.27180.030*
C90.4878 (3)0.12953 (9)0.0736 (2)0.0158 (4)
H9A0.53420.12570.17520.019*
H9B0.56970.10480.03010.019*
C100.2853 (3)0.10399 (9)0.0281 (2)0.0148 (4)
C110.4965 (3)0.36335 (9)0.0885 (2)0.0177 (4)
H11A0.58670.38660.04980.021*
H11B0.54410.36310.19050.021*
C120.3065 (3)0.39821 (9)0.0510 (2)0.0161 (4)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Zn10.01524 (18)0.01194 (17)0.01867 (19)−0.00014 (13)0.00336 (13)0.00262 (13)
O10.0199 (8)0.0220 (8)0.0262 (9)0.0010 (6)0.0010 (7)−0.0064 (7)
O20.0242 (8)0.0161 (7)0.0239 (8)0.0047 (6)−0.0003 (6)−0.0044 (6)
O30.0157 (7)0.0157 (7)0.0272 (8)−0.0005 (6)0.0012 (6)0.0060 (6)
O40.0188 (8)0.0136 (7)0.0232 (8)−0.0020 (6)0.0026 (6)0.0051 (6)
O50.0179 (9)0.0242 (8)0.0203 (8)0.0002 (7)0.0038 (7)0.0043 (7)
O60.0195 (8)0.0168 (8)0.0228 (9)−0.0008 (6)0.0029 (7)0.0020 (7)
O70.0241 (10)0.0240 (9)0.0343 (10)0.0040 (7)0.0100 (8)0.0077 (8)
O80.0202 (9)0.0270 (9)0.0290 (10)0.0038 (8)0.0056 (8)0.0048 (8)
N10.0157 (8)0.0103 (8)0.0185 (9)−0.0002 (7)0.0041 (7)−0.0001 (7)
N20.0150 (8)0.0112 (8)0.0166 (9)−0.0021 (7)0.0025 (7)0.0012 (7)
C10.0128 (10)0.0168 (10)0.0173 (10)0.0001 (8)0.0033 (8)0.0002 (8)
C20.0187 (10)0.0161 (10)0.0243 (12)−0.0007 (8)0.0053 (9)0.0055 (9)
C30.0211 (11)0.0289 (12)0.0203 (11)0.0016 (9)0.0080 (9)0.0073 (9)
C40.0219 (11)0.0276 (12)0.0192 (11)0.0013 (9)0.0073 (9)−0.0015 (9)
C50.0191 (11)0.0176 (11)0.0223 (11)0.0001 (8)0.0065 (9)−0.0015 (9)
C60.0131 (10)0.0157 (10)0.0170 (10)−0.0001 (8)0.0040 (8)0.0014 (8)
C70.0110 (9)0.0132 (10)0.0184 (10)−0.0004 (8)0.0011 (8)−0.0005 (8)
C80.0212 (11)0.0194 (11)0.0178 (11)−0.0007 (9)0.0033 (9)−0.0012 (8)
C90.0172 (10)0.0095 (9)0.0202 (11)0.0005 (8)0.0036 (8)0.0018 (8)
C100.0173 (10)0.0141 (10)0.0136 (10)0.0007 (8)0.0048 (8)−0.0023 (8)
C110.0190 (11)0.0119 (9)0.0217 (11)0.0002 (8)0.0038 (8)−0.0032 (8)
C120.0175 (10)0.0131 (10)0.0181 (10)0.0003 (8)0.0052 (8)0.0017 (8)

Geometric parameters (Å, °)

Zn1—O52.1023 (17)N2—C61.398 (3)
Zn1—O5i2.1023 (17)N2—C91.463 (2)
Zn1—O6i2.1128 (16)C1—C61.390 (3)
Zn1—O62.1128 (16)C1—C21.396 (3)
Zn1—O42.1303 (14)C2—C31.384 (3)
Zn1—O4i2.1303 (14)C2—H2A0.9300
O1—C121.233 (3)C3—C41.402 (3)
O2—C121.273 (2)C3—H3A0.9300
O3—C101.247 (2)C4—C51.392 (3)
O4—C101.261 (2)C4—H4A0.9300
O5—H5A0.71 (3)C5—C61.389 (3)
O5—H5B0.80 (4)C5—H5C0.9300
O6—H6A0.92 (4)C7—C81.476 (3)
O6—H6B0.75 (3)C8—H8C0.9600
O7—H7A0.78 (4)C8—H8D0.9600
O7—H7B0.78 (4)C8—H8E0.9600
O8—H8A0.75 (3)C9—C101.528 (3)
O8—H8B0.79 (3)C9—H9A0.9700
N1—C71.345 (3)C9—H9B0.9700
N1—C11.394 (3)C11—C121.531 (3)
N1—C111.466 (3)C11—H11A0.9700
N2—C71.341 (3)C11—H11B0.9700
O5—Zn1—O5i180.00 (14)C4—C3—H3A118.8
O5—Zn1—O6i91.13 (7)C5—C4—C3121.7 (2)
O5i—Zn1—O6i88.87 (7)C5—C4—H4A119.2
O5—Zn1—O688.87 (7)C3—C4—H4A119.2
O5i—Zn1—O691.13 (7)C6—C5—C4115.6 (2)
O6i—Zn1—O6180.00 (9)C6—C5—H5C122.2
O5—Zn1—O489.65 (7)C4—C5—H5C122.2
O5i—Zn1—O490.35 (7)C5—C6—C1122.7 (2)
O6i—Zn1—O484.78 (6)C5—C6—N2130.64 (19)
O6—Zn1—O495.22 (6)C1—C6—N2106.58 (18)
O5—Zn1—O4i90.35 (7)N2—C7—N1109.18 (18)
O5i—Zn1—O4i89.65 (7)N2—C7—C8125.07 (19)
O6i—Zn1—O4i95.22 (6)N1—C7—C8125.74 (19)
O6—Zn1—O4i84.78 (6)C7—C8—H8C109.5
O4—Zn1—O4i180.00 (12)C7—C8—H8D109.5
C10—O4—Zn1122.18 (13)H8C—C8—H8D109.5
Zn1—O5—H5A106 (3)C7—C8—H8E109.5
Zn1—O5—H5B114 (2)H8C—C8—H8E109.5
H5A—O5—H5B108 (4)H8D—C8—H8E109.5
Zn1—O6—H6A93 (2)N2—C9—C10111.03 (16)
Zn1—O6—H6B104 (2)N2—C9—H9A109.4
H6A—O6—H6B104 (3)C10—C9—H9A109.4
H7A—O7—H7B106 (4)N2—C9—H9B109.4
H8A—O8—H8B113 (3)C10—C9—H9B109.4
C7—N1—C1108.75 (17)H9A—C9—H9B108.0
C7—N1—C11126.66 (18)O3—C10—O4126.52 (19)
C1—N1—C11124.53 (17)O3—C10—C9117.38 (18)
C7—N2—C6108.77 (17)O4—C10—C9116.09 (17)
C7—N2—C9126.57 (17)N1—C11—C12114.77 (17)
C6—N2—C9124.43 (17)N1—C11—H11A108.6
C6—C1—N1106.69 (18)C12—C11—H11A108.6
C6—C1—C2121.8 (2)N1—C11—H11B108.6
N1—C1—C2131.5 (2)C12—C11—H11B108.6
C3—C2—C1115.8 (2)H11A—C11—H11B107.6
C3—C2—H2A122.1O1—C12—O2126.3 (2)
C1—C2—H2A122.1O1—C12—C11120.08 (18)
C2—C3—C4122.4 (2)O2—C12—C11113.60 (18)
C2—C3—H3A118.8
O5—Zn1—O4—C10−107.15 (16)C7—N2—C6—C11.1 (2)
O5i—Zn1—O4—C1072.85 (16)C9—N2—C6—C1175.92 (17)
O6i—Zn1—O4—C10161.69 (16)C6—N2—C7—N1−1.8 (2)
O6—Zn1—O4—C10−18.31 (16)C9—N2—C7—N1−176.41 (17)
C7—N1—C1—C6−1.0 (2)C6—N2—C7—C8176.87 (19)
C11—N1—C1—C6176.50 (17)C9—N2—C7—C82.2 (3)
C7—N1—C1—C2176.8 (2)C1—N1—C7—N21.7 (2)
C11—N1—C1—C2−5.7 (3)C11—N1—C7—N2−175.70 (17)
C6—C1—C2—C31.0 (3)C1—N1—C7—C8−176.92 (19)
N1—C1—C2—C3−176.5 (2)C11—N1—C7—C85.7 (3)
C1—C2—C3—C40.4 (3)C7—N2—C9—C1096.0 (2)
C2—C3—C4—C5−1.4 (3)C6—N2—C9—C10−77.8 (2)
C3—C4—C5—C60.9 (3)Zn1—O4—C10—O39.4 (3)
C4—C5—C6—C10.5 (3)Zn1—O4—C10—C9−170.20 (13)
C4—C5—C6—N2176.3 (2)N2—C9—C10—O39.8 (3)
N1—C1—C6—C5176.56 (18)N2—C9—C10—O4−170.54 (17)
C2—C1—C6—C5−1.5 (3)C7—N1—C11—C12−103.4 (2)
N1—C1—C6—N2−0.1 (2)C1—N1—C11—C1279.6 (2)
C2—C1—C6—N2−178.15 (18)N1—C11—C12—O1−17.0 (3)
C7—N2—C6—C5−175.2 (2)N1—C11—C12—O2163.61 (18)
C9—N2—C6—C5−0.4 (3)

Symmetry codes: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O5—H5B···O80.80 (4)1.92 (4)2.716 (3)170 (3)
O6—H6A···O30.92 (4)1.70 (4)2.610 (2)170 (3)
O6—H6B···O2ii0.75 (3)2.08 (3)2.811 (2)164 (3)
O7—H7A···O1iii0.78 (4)2.11 (4)2.864 (3)165 (4)
O7—H7B···O2iv0.78 (4)2.03 (4)2.792 (2)167 (3)
O8—H8A···O4iv0.75 (3)2.10 (3)2.846 (2)177 (3)
O8—H8B···O7v0.79 (3)2.00 (3)2.786 (3)168 (3)

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HK2732).

References

  • Bruker (1998). SMART and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Kitagawa, S., Kitaura, R. & Noro, S. (2004). Angew. Chem. Int. Ed.43, 2334–2375. [PubMed]
  • Ni, Q.-L., Li, F.-S., Jin, L.-L., He, P.-X. & Wang, X.-J. (2007). Chem. Res. Appl. (Chin. J.), 19, 1181–1184.
  • Robson, R. (2000). J. Chem. Soc. Dalton Trans. pp. 3735–3744.
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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