Bis(1H-imidazole-κN 3)bis­(2-oxidopyridinium-3-carboxyl­ato-κ2 O 2,O 3)nickel(II)

Bing-Yu Zhang; Jing-Jing Nie; Duan-Jun Xu

doi:10.1107/S1600536809028347

. 2009 Jul 22;65(Pt 8):m977. doi: 10.1107/S1600536809028347

Bis(1H-imidazole-κN ³)bis(2-oxidopyridinium-3-carboxylato-κ² O ²,O ³)nickel(II)

Bing-Yu Zhang ^a, Jing-Jing Nie ^a, Duan-Jun Xu ^a,^*

PMCID: PMC2977237 PMID: 21583420

Abstract

In the crystal structure of the title Ni^II complex, [Ni(C₆H₄NO₃)₂(C₃H₄N₂)₂], the Ni^II atom is located on a twofold rotation axis and is chelated by two oxidopyridiniumcarboxylate anions and further cis-coordinated by two imidazole ligands in a distorted cis-N₂O₄ octahedral geometry. The C—O bond distance of 1.2573 (19) Å found for the non-coordinating O atom of the carboxylate group indicates significant delocalization of π-electron density over this residue. Similarly, the C—O bond distance of 1.260 (2) Å in the heteroaromatic ring indicates delocalization between the deprotonated hydroxy group and the pyridinium ring. The uncoordinated carboxylate O atom links with the imidazole and pyridinium rings of adjacent molecules via N—H⋯O and C—H⋯O hydrogen bonding, leading to a two-dimensional array parallel to (100).

Related literature

For the nature of π-π stacking, see: Deisenhofer & Michel (1989 ▶); Xu et al. (2007 ▶); Li et al. (2005 ▶). For the short C—O bond distance between a pyridine ring and hydroxy-O atom in metal complexes of 2-oxidopyridinium-3-carboxylate, see: Yao et al. (2004 ▶); Yan & Hu (2007a ▶,b ▶); Wen & Liu (2007 ▶).

Experimental

Crystal data

[Ni(C₆H₄NO₃)₂(C₃H₄N₂)₂]
M _r = 471.08
Monoclinic,
a = 16.5603 (12) Å
b = 9.9687 (7) Å
c = 12.7981 (9) Å
β = 111.203 (2)°
V = 1969.7 (2) Å³
Z = 4
Mo Kα radiation
μ = 1.04 mm⁻¹
T = 294 K
0.28 × 0.22 × 0.18 mm

Data collection

Rigaku R-AXIS RAPID IP diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.730, T _max = 0.830
10787 measured reflections
1934 independent reflections
1690 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.025
wR(F ²) = 0.067
S = 1.09
1934 reflections
141 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1993 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809028347/tk2499sup1.cif

e-65-0m977-sup1.cif^{(15.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809028347/tk2499Isup2.hkl

e-65-0m977-Isup2.hkl^{(93.3KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2ⁱ	0.86	1.93	2.7848 (19)	177
N3—H3⋯O2ⁱⁱ	0.86	2.03	2.796 (2)	148
C3—H3A⋯O3ⁱⁱⁱ	0.93	2.41	3.323 (2)	167

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The project was supported by the ZIJIN project of Zhejiang University, China.

supplementary crystallographic information

Comment

As π-π stacking between aromatic rings is correlated with electron transfer process in some biological systems (Deisenhofer & Michel, 1989), metal complexes incorporating aromatic ligands have attracted much attention. As a part of an on-going investigation of π-π stacking (Xu et al., 2007a, b; Li et al., 2005), the title complex, (I), has been prepared and its crystal structure reported herein.

The analysis of (I) shows the Ni atom to be located on a 2-fold axis and to be chelated by two oxidopyridinium-carboxylate anions and two cis-orientated imidazole ligands to complete a distorted octahedral coordination geometry (Fig. 1). The carboxylate group is twisted with respect to the benzene ring with a dihedral angle of 22.09 (11)°. The C1—O3 bond distance of 1.260 (2) Å is much shorter than a normal single C—O bond, indicating delocalization of π-electron density over the deprotonated hydroxy group and the pyridinium ring, an observation which agrees with similiar features found in the other transition metal complexes of oxidopyridinium-carboxylate (Yao et al., 2004; Yan & Hu, 2007a,b; Wen & Liu, 2007).

The uncoordinated carboxyl-O atom simutaneously links the imidazole and pyridinium rings via N—H···O hydrogen bonding leading to a 2-D array (Table 2). Weak C—H···O hydrogen bonding is also present in the crystal structure but no π-π stacking is evident.

Experimental

2-Hydroxy-pyridine-3-carboxylic acid (0.13 g, 1 mmol), NaOH (0.04 g, 1 mmol), imidazole (0.14 g, 2 mmol) and NiCl₂.6H₂O (0.24 g, 1 mmol) were dissolved in water (15 ml). The solution was refluxed for 4.5 h. After cooling to room temperature, the solution was filtered. Single crystals of (I) were obtained from the filtrate after one week.