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

Lian, H.-C.; Ni, Q.-L.; Jiang, X.-F.; Cen, Z.-M.; Lin, J.-H.

doi:10.1107/S1600536809031766

Volume 65
Part 9
Page m1091
September 2009

Received 30 June 2009
Accepted 12 August 2009
Online 19 August 2009

Key indicators
Single-crystal X-ray study
T = 294 K
Mean (C-C) = 0.003 Å
R = 0.036
wR = 0.097
Data-to-parameter ratio = 13.5
Details

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

Heng-Chi Lian,^a ^* Qing-Ling Ni,^a Xuan-Feng Jiang,^a Zhong-Min Cen ^a and Jia-Huang Lin ^a

^aSchool of Chemistry and Chemical Engineering, Guangxi Normal University, Guilin 541004, People's Republic of China
Correspondence e-mail: lianhengchi@yahoo.com.cn

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 Zn^II centre ( $[\overline 1]$ 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-HO hydrogen bonding results in the formation of a non-planar six-membered ring. In the crystal structure, strong intra- and intermolecular O-HO hydrogen bonds link the molecules into a three-dimensional network. [pi] - [pi] 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); Kitagawa et al. (2004). For a related structure, see: Ni et al. (2007).

Experimental

Crystal data

[Zn(C₁₂H₁₁N₂O₄)₂(H₂O)₄]·4H₂O
M_r = 703.95
Monoclinic, P 2₁ /n
a = 7.2749 (9) Å
b = 21.265 (3) Å
c = 9.7794 (12) Å
= 104.467 (2)°
V = 1464.9 (3) Å³
Z = 2
Mo K radiation
= 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) T_min = 0.757, T_max = 0.874
7436 measured reflections
3202 independent reflections
2582 reflections with I > 2(I)
R_int = 0.022

Refinement

R[F² > 2(F²)] = 0.036
wR(F²) = 0.097
S = 1.10
3202 reflections
237 parameters
H atoms treated by a mixture of independent and constrained refinement
_max = 0.98 e Å^-3
_min = -0.51 e Å^-3

Table 1
Selected geometric parameters (Å, °)

Zn1-O5	2.1023 (17)
Zn1-O6	2.1128 (16)
Zn1-O4	2.1303 (14)

Table 2
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
O5-H5BO8	0.80 (4)	1.92 (4)	2.716 (3)	170 (3)
O6-H6AO3	0.92 (4)	1.70 (4)	2.610 (2)	170 (3)
O6-H6BO2ⁱⁱ	0.75 (3)	2.08 (3)	2.811 (2)	164 (3)
O7-H7AO1ⁱⁱⁱ	0.78 (4)	2.11 (4)	2.864 (3)	165 (4)
O7-H7BO2^iv	0.78 (4)	2.03 (4)	2.792 (2)	167 (3)
O8-H8AO4^iv	0.75 (3)	2.10 (3)	2.846 (2)	177 (3)
O8-H8BO7^v	0.79 (3)	2.00 (3)	2.786 (3)	168 (3)
Symmetry codes: (ii) $[x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iii) -x-1, -y+1, -z; (iv) x-1, y, z; (v) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; 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.

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

Acknowledgements

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.

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.
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.

metal-organic compounds