Bis(2,2′-bipyridine-κ2 N,N′)(croconato-κ2 O,O′)nickel(II)

Hong-Feng Chen; Qi Fang; Wen-Tao Yu

doi:10.1107/S1600536808033771

. 2008 Oct 25;64(Pt 11):m1459. doi: 10.1107/S1600536808033771

Bis(2,2′-bipyridine-κ² N,N′)(croconato-κ² O,O′)nickel(II)

Hong-Feng Chen ^a, Qi Fang ^a,^*, Wen-Tao Yu ^a

PMCID: PMC2959560 PMID: 21580897

Abstract

The title compound, [Ni(C₅O₅)(C₁₀H₈N₂)₂], lies across a crystallographic twofold axis, around which two 2,2′-bipyridine (2,2′-bipy) ligands are arranged in a propeller manner. The local geometry of the NiN₄O₂ coordination core basically adopts an octahedral geometry. The molecular twofold axis is along the direction of the molecular dipole moment, and the complex is packed with its dipole moment alternately along the +b and −b directions. The crystal structure is stabilized by intermolecular C—H⋯O hydrogen bonds.

Related literature

For the synthesis, see: Chen et al. (2008 ▶). For related structures, see: Chen et al. (2005 ▶, 2007 ▶). For other related literature, see: Coronado et al. (2007 ▶); Wang et al. (2002 ▶).

Experimental

Crystal data

[Ni(C₅O₅)(C₁₀H₈N₂)₂]
M _r = 511.13
Orthorhombic,
a = 12.725 (5) Å
b = 10.752 (5) Å
c = 15.733 (5) Å
V = 2152.6 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.95 mm⁻¹
T = 293 (2) K
0.20 × 0.19 × 0.10 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (APEX2; Bruker, 2005 ▶) T _min = 0.821, T _max = 0.902
10055 measured reflections
2466 independent reflections
1536 reflections with I > 2σ(I)
R _int = 0.089

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.102
S = 1.02
2466 reflections
160 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: APEX2; 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: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808033771/lx2071sup1.cif

e-64-m1459-sup1.cif^{(18.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808033771/lx2071Isup2.hkl

e-64-m1459-Isup2.hkl^{(121.3KB, 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
C4—H4⋯O1ⁱ	0.93	2.57	3.340 (4)	141
C8—H8⋯O2ⁱⁱ	0.93	2.24	3.114 (4)	156
C9—H9⋯O3ⁱⁱⁱ	0.93	2.57	3.222 (4)	127

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

Acknowledgments

This work was supported by the PhD Foundation of the Ministry of Education of China and by the National Natural Science Foundation of China (grant No. 50673054).

supplementary crystallographic information

Comment

The croconate C₅O₅^2- anion has attracted increasing attention in recent years because this polydentate ligand gave rise to a variety of interesting complexes (Chen et al., 2008; Coronado et al., 2007; Chen et al., 2005; Wang et al., 2002;). Typically, the C₅O₅^2- anion serves as a terminal bidentate chelate ligand or a bridging ligand utilizing more than two O atoms for coordination. We previously reported a mixing-coordinated complex [Ni(C₅O₅)(phen)₂] with 1,10-phenanthroline (phen) as the first ligand and the C₅O₅^2- anion as the second ligand (Chen et al., 2007). The similar chelating behavior of 2,2'-bipy and 1,10-phen prompted us to replace phen ligand by 2,2'-bipy. In this report, the structure of this mixing-coordinated complex is reported.

The title compound crystalizes to the same space group as [Ni(C₅O₅)(phen)₂]. Both crystals have very similar cell parameters and show many common features. The chiral molecule lies across twofold axis which is along the direction of the molecular dipole moment. Around the molecular axis, two 2,2'-bipy ligands are arranged in a propeller manner. The Ni²⁺ is coordinated by four N atoms of the two 2,2'-bipy ligands and two O atoms of a croconate ligand to furnish a slightly distored octahedral NiN₄O₂ coordination core. The dihedral angle between the croconate plane and a 2,2'-bipy plane is 88.7 (1)°, and that between the two 2,2'-bipy planes is 81.9 (1)° in [Ni(C₅O₅) (2,2'-bipy)₂]. These are close to the corresponding dihedral angles (86.9 (1)° and 86.6 (1)°) in [Ni(C₅O₅)(phen)₂]. The C—O bond lengths involving coordinated O atoms are longer than those of other C—O bonds. In both crystals, molecules packed alternately along +b and-b directions.

However, we can not fail to notice some differences between the two crystals. The Ni—O band length of [Ni(C₅O₅)(2,2'-bipy)₂] {2.102 (2) Å} is longer than that {2.098 (3) Å} of [Ni(C₅O₅)(phen)₂]. Meanwhile, the Ni—N band lengths of [Ni(C₅O₅)(2,2'-bipy)₂] {2.059 (2), 2.066 (2) Å} is considerably shorter than those {2.071 (3), 2.088 (3) Å} of [Ni(C₅O₅)(phen)₂]. It seems that 2,2'-bipyridine is a stronger ligand to Ni²⁺ in comparison with 1,10-phenanthroline. The crystal structure is stabilized by intermolecular C—H···O hydrogen bonds (Table 1).

Experimental

[K₂(C₅O₅)] (0.050 g, 0.23 mmol) and NiCl₂.6H₂O (0.060 g, 0.25 mmol) were dissolved in mixed solvent of water (15 ml) and dimethylformamide (10 ml). Then 2,2'-bipy (0.080 g, 0.51 mmol) was added. The mixture was heated to 340–350 K under continuous stirring for 20 min and then filtered. The green-yellow prisms crystals were obtained by slow evaporation at 313 K.