{5,5′-Dihydr­oxy-2,2′-[o-phenyl­enebis­(nitrilo­methyl­idyne)]diphenolato}nickel(II) dihydrate

Hoong-Kun Fun; Reza Kia; Valiollah Mirkhani; Hasan Zargoshi

doi:10.1107/S1600536808026093

. 2008 Aug 16;64(Pt 9):m1181–m1182. doi: 10.1107/S1600536808026093

{5,5′-Dihydroxy-2,2′-[o-phenylenebis(nitrilomethylidyne)]diphenolato}nickel(II) dihydrate

Hoong-Kun Fun ^a,^*, Reza Kia ^a,^‡, Valiollah Mirkhani ^b,^§, Hasan Zargoshi ^b

PMCID: PMC2960688 PMID: 21201624

Abstract

In the title complex, [Ni(C₂₀H₁₄N₂O₄)]·2H₂O, the Ni^II ion is in an essentially square-planar geometry involving an N₂O₂ atom set of the tetradentate Schiff base ligand. The Ni atom lies on a crystallographic twofold rotation axis. The asymmetric unit contains one half-molecule of the complex and a water molecule. An intermolecular O—H⋯O hydrogen bond forms a four-membered ring, producing an R ₁ ²(4) ring motif involving a bifurcated hydrogen bond to the phenolate O atoms of the complex molecule. In the crystal structure, molecules are linked by π–π stacking interactions, with centroid–centroid distances in the range 3.5750 (11)–3.7750 (11) Å. As a result of the twofold symmetry, the central benzene ring makes the same dihedral angle of 15.75 (9)° with the two outer benzene rings. The dihedral angle between the two hydroxyphenyl rings is 13.16 (5)°. In the crystal structure, molecules are linked into infinite one-dimensional chains by directed four-membered O—H⋯O—H interactions along the c axis and are further connected by C—H⋯O and π–π stacking into a three-dimensional network. An interesting feature of the crystal structure is the short Ni⋯O, O⋯O and N⋯N interactions which are shorter than the sum of the van der Waals radii of the relevant atoms. The crystal structure is stabilized by intermolecular O—H⋯O and C—H⋯O hydrogen bonds and by π–π stacking interactions.

Related literature

For bond-length data, see Allen et al. (1987 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For related structures, see, for example: Clark et al. (1968 ▶, 1969 ▶, 1970 ▶); Hodgson 1975 ▶. For applications and bioactivities, see, for example: Elmali et al. (2000 ▶); Blower (1998 ▶); Granovski et al. (1993 ▶); Li & Chang (1991 ▶); Shahrokhian et al. (2000 ▶); Fun & Kia (2008a ▶,b ▶).

Experimental

Crystal data

[Ni(C₂₀H₁₄N₂O₄)]·2H₂O
M _r = 441.07
Monoclinic,
a = 10.9049 (2) Å
b = 17.6602 (3) Å
c = 9.0375 (3) Å
β = 101.150 (1)°
V = 1707.61 (7) Å³
Z = 4
Mo Kα radiation
μ = 1.18 mm⁻¹
T = 100.0 (1) K
0.35 × 0.12 × 0.11 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.683, T _max = 0.881
14574 measured reflections
3566 independent reflections
2388 reflections with I > 2σ(I)
R _int = 0.046

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.120
S = 1.12
3566 reflections
136 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.61 e Å⁻³
Δρ_min = −0.73 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808026093/pk2114sup1.cif

e-64-m1181-sup1.cif^{(17.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808026093/pk2114Isup2.hkl

e-64-m1181-Isup2.hkl^{(175KB, hkl)}

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

Table 1. Selected interatomic distances (Å).

Cg1, Cg2, Cg3, and Cg4 are the centroids of the Ni1/N1/C8/C8A/N1A, Ni1/O1/C1/C6/C7/N1, Ni1/O1A/C1A/C6A/C7A/N1A and C1–C6 rings, respectively.

Cg1⋯Cg4ⁱ	3.7364 (11)
Cg2⋯Cg2ⁱ	3.7380 (9)
Cg2⋯Cg3ⁱⁱ	3.7381 (9)
Cg3⋯Cg4ⁱⁱⁱ	3.5766 (10)
Cg4⋯Cg4^iv	3.7750 (11)
Ni1⋯O1W^v	3.7635 (13)
O1⋯O1^v	2.4319 (18)
N1⋯N1^v	2.525 (2)

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

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W1⋯O1	0.88	2.40	3.0733 (18)	133
O1W—H1W1⋯O1^v	0.88	1.97	2.8072 (19)	160
O1W—H2W1⋯O2^vi	0.83	2.17	2.9985 (19)	173
C9—H9A⋯O2^vii	0.93	2.60	3.394 (2)	144

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Symmetry codes: (v) Inline graphic ; (vi) ; (vii) .

Acknowledgments

HKF and RK thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. RK thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

Schiff base complexes are some of the most important stereochemical models in transition metal coordination chemistry, with their ease of preparation and structural variations (Granovski et al., 1993). Many of the reported structural investigations of these complexes are discussed in some details in a review (Hodgson, 1975). Metal derivatives of Schiff bases have been studied extensively, and Cu(II) and Ni(II) complexes play a major role in both synthetic and structural research (Elmali et al., 2000; Blower, 1998; Fun & Kia, 2008a,b; Granovski et al., 1993; Li & Chang, 1991; Shahrokhian et al., 2000). Tetradentate Schiff base metal complexes may form trans or cis planar or tetrahedral structures (Elmali et al., 2000).

In the title compound (Fig. 1), the Ni^II ion, is in an essentially square-planar geometry involving a N₂O₂ atom set of the tetradentate Schiff base ligand. The Ni atom lies on a crystallographic twofold rotation axis. An intermolecular O—H···O hydrogen bond forms a four-membered ring, producing an R²₁(4) ring motif (Bernstein et al., 1995). The bond lengths are within the normal ranges (Allen et al., 1987). The asymmetric unit contains one-half of the molecule of the complex and a water molecule. The latter shows a bifurcated hydrogen bond which is connected to the phenolato oxygen atoms of the complex. The molecule is nearly planar, with a maximum deviation from the mean plane of 0.370 (2) Å for atom C9. As a result of the twofold symmetry, the central benzene ring makes the same dihedral angle of 15.75 (9)° with the two outer benzene rings. The dihedral angle between the two hydroxy phenyl rings is 13.16 (5)°. In the crystal structure, (Fig. 2) molecules are linked into infinite one-dimensional chains by directed four-membered O—H···O—H interactions along the c axis and are furthered connected by C—H···O and π-π stacking into a three-dimensional network.

An interesting feature of the crystal structure is the short Ni···O, O···O, and N···N interactions (Table 1), which are shorter than the sum of the van der Waals radii of the relevant atoms. The short distances between the centroids of the five- and six-membered rings indicate the existence of the π-π interactions (Table 1). The crystal structure is stabilized by intermolecular O—H···O, C—H···O hydrogen bonds (Table 2) and π-π interactions.

Experimental

A chloroform solution (40 ml) of the ligand (1 mmol, 354 mg) was added to a methanol solution (20 ml) of NiCl₂.6H₂O (1.05 mmol, 237 mg). The mixture was refluxed for 30 min and the resulting red precipitate was filtered, washed with cold ethanol and dried in air. Single crystals suitable for X-ray analysis were obtained from a THF solution at RT.