metal-organic compounds
{5,5′-Dihydroxy-2,2′-[o-phenylenebis(nitrilomethylidyne)]diphenolato}nickel(II) dihydrate
aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bChemistry Department, Isfahan University, Isfahan, 81746-73441, Iran
*Correspondence e-mail: hkfun@usm.my
In the title complex, [Ni(C20H14N2O4)]·2H2O, the NiII 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 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 R12(4) ring motif involving a bifurcated hydrogen bond to the phenolate O atoms of the complex molecule. In the 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 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 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 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
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Refinement
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Data collection: APEX2 (Bruker, 2005); cell 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).
Supporting information
10.1107/S1600536808026093/pk2114sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808026093/pk2114Isup2.hkl
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.
The water H-atoms were located in a difference Fourier map and refined as riding on the parent atom with an isotropic displacement parameter of 1.5Ueq of the water oxygen. The hydroxyl H atoms were also located in a difference Fourier map and refined freely. The rest of the hydrogen atoms were positioned geometrically [C—H = 0.93 Å] and refined using a riding model.
Data collection: APEX2 (Bruker, 2005); cell
APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering scheme. Intermolecular hydrogen bonds are drawn as dashed lines. | |
Fig. 2. The crystal packing viewed down the b axis, showing one-dimensional extended chains involving the directed four membered O—H···O—H hydrogen bonds along the c axis. Intermolecular interactions are drawn as dashed lines. |
[Ni(C20H14N2O4)]·2H2O | F(000) = 912 |
Mr = 441.07 | Dx = 1.716 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 3113 reflections |
a = 10.9049 (2) Å | θ = 2.3–29.1° |
b = 17.6602 (3) Å | µ = 1.18 mm−1 |
c = 9.0375 (3) Å | T = 100 K |
β = 101.150 (1)° | Block, red |
V = 1707.61 (7) Å3 | 0.35 × 0.12 × 0.11 mm |
Z = 4 |
Bruker SMART APEXII CCD area-detector diffractometer | 3566 independent reflections |
Radiation source: fine-focus sealed tube | 2388 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.046 |
ϕ and ω scans | θmax = 34.3°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −17→17 |
Tmin = 0.683, Tmax = 0.881 | k = −23→27 |
14574 measured reflections | l = −14→14 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.121 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.12 | w = 1/[σ2(Fo2) + (0.0492P)2] where P = (Fo2 + 2Fc2)/3 |
3566 reflections | (Δ/σ)max < 0.001 |
136 parameters | Δρmax = 0.61 e Å−3 |
0 restraints | Δρmin = −0.74 e Å−3 |
[Ni(C20H14N2O4)]·2H2O | V = 1707.61 (7) Å3 |
Mr = 441.07 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 10.9049 (2) Å | µ = 1.18 mm−1 |
b = 17.6602 (3) Å | T = 100 K |
c = 9.0375 (3) Å | 0.35 × 0.12 × 0.11 mm |
β = 101.150 (1)° |
Bruker SMART APEXII CCD area-detector diffractometer | 3566 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 2388 reflections with I > 2σ(I) |
Tmin = 0.683, Tmax = 0.881 | Rint = 0.046 |
14574 measured reflections |
R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
wR(F2) = 0.121 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.12 | Δρmax = 0.61 e Å−3 |
3566 reflections | Δρmin = −0.74 e Å−3 |
136 parameters |
Experimental. The low-temperature data was collected with the Oxford Cryosystem Cobra low-temperature attachment |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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. |
x | y | z | Uiso*/Ueq | ||
Ni1 | 0.0000 | 0.246535 (17) | 0.7500 | 0.01493 (11) | |
O1 | 0.04391 (12) | 0.32501 (7) | 0.88434 (14) | 0.0174 (3) | |
O2 | 0.18665 (13) | 0.44913 (8) | 1.35074 (15) | 0.0215 (3) | |
N1 | 0.06039 (14) | 0.17016 (8) | 0.88409 (17) | 0.0152 (3) | |
C1 | 0.09715 (16) | 0.32009 (10) | 1.0287 (2) | 0.0159 (4) | |
C2 | 0.11546 (17) | 0.38691 (10) | 1.1132 (2) | 0.0175 (4) | |
H2A | 0.0908 | 0.4329 | 1.0668 | 0.021* | |
C3 | 0.16965 (17) | 0.38546 (10) | 1.2647 (2) | 0.0161 (4) | |
C4 | 0.21006 (17) | 0.31684 (11) | 1.3364 (2) | 0.0200 (4) | |
H4A | 0.2474 | 0.3160 | 1.4380 | 0.024* | |
C5 | 0.1937 (2) | 0.25113 (10) | 1.2545 (2) | 0.0192 (4) | |
H5A | 0.2218 | 0.2058 | 1.3015 | 0.023* | |
C6 | 0.13518 (18) | 0.25029 (10) | 1.1002 (2) | 0.0160 (3) | |
C7 | 0.11768 (17) | 0.17979 (10) | 1.0251 (2) | 0.0172 (4) | |
H7A | 0.1490 | 0.1369 | 1.0793 | 0.021* | |
C8 | 0.03852 (17) | 0.09645 (10) | 0.8211 (2) | 0.0181 (4) | |
C9 | 0.08370 (18) | 0.02822 (10) | 0.8878 (2) | 0.0206 (4) | |
H9A | 0.1404 | 0.0281 | 0.9790 | 0.025* | |
C10 | 0.04344 (18) | −0.03919 (11) | 0.8171 (2) | 0.0232 (4) | |
H10A | 0.0748 | −0.0849 | 0.8598 | 0.028* | |
O1W | 0.15531 (13) | 0.42836 (7) | 0.67062 (15) | 0.0240 (3) | |
H1W1 | 0.0971 | 0.3950 | 0.6774 | 0.036* | |
H2W1 | 0.1630 | 0.4380 | 0.5829 | 0.036* | |
H1O2 | 0.170 (2) | 0.4836 (15) | 1.304 (3) | 0.047 (9)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ni1 | 0.01935 (18) | 0.01096 (18) | 0.01281 (16) | 0.000 | −0.00102 (12) | 0.000 |
O1 | 0.0240 (7) | 0.0128 (6) | 0.0126 (6) | 0.0004 (5) | −0.0033 (5) | −0.0004 (5) |
O2 | 0.0320 (8) | 0.0146 (7) | 0.0156 (6) | −0.0001 (6) | −0.0007 (6) | −0.0040 (6) |
N1 | 0.0177 (7) | 0.0109 (7) | 0.0161 (7) | −0.0006 (6) | 0.0012 (6) | −0.0003 (6) |
C1 | 0.0189 (8) | 0.0149 (9) | 0.0129 (8) | 0.0002 (7) | 0.0002 (7) | 0.0020 (7) |
C2 | 0.0201 (9) | 0.0156 (9) | 0.0148 (8) | −0.0007 (7) | −0.0012 (7) | 0.0009 (7) |
C3 | 0.0192 (9) | 0.0142 (9) | 0.0145 (8) | −0.0009 (7) | 0.0020 (7) | −0.0020 (7) |
C4 | 0.0260 (10) | 0.0209 (10) | 0.0111 (8) | 0.0015 (8) | −0.0011 (7) | 0.0013 (7) |
C5 | 0.0256 (10) | 0.0168 (9) | 0.0139 (8) | 0.0010 (7) | 0.0006 (7) | 0.0047 (7) |
C6 | 0.0189 (8) | 0.0154 (9) | 0.0126 (7) | −0.0004 (7) | 0.0004 (6) | 0.0010 (7) |
C7 | 0.0215 (9) | 0.0132 (9) | 0.0158 (8) | 0.0007 (7) | 0.0009 (7) | 0.0040 (7) |
C8 | 0.0192 (9) | 0.0151 (9) | 0.0188 (9) | 0.0006 (7) | 0.0011 (7) | 0.0016 (7) |
C9 | 0.0224 (9) | 0.0173 (9) | 0.0207 (9) | 0.0005 (8) | 0.0007 (7) | 0.0022 (8) |
C10 | 0.0293 (11) | 0.0153 (9) | 0.0252 (10) | 0.0014 (8) | 0.0055 (8) | 0.0039 (8) |
O1W | 0.0312 (8) | 0.0175 (7) | 0.0232 (7) | −0.0055 (6) | 0.0050 (6) | 0.0009 (6) |
Ni1—O1 | 1.8436 (12) | C4—C5 | 1.369 (3) |
Ni1—O1i | 1.8436 (12) | C4—H4A | 0.9300 |
Ni1—N1i | 1.8474 (15) | C5—C6 | 1.417 (3) |
Ni1—N1 | 1.8474 (15) | C5—H5A | 0.9300 |
O1—C1 | 1.324 (2) | C6—C7 | 1.414 (2) |
O2—C3 | 1.359 (2) | C7—H7A | 0.9300 |
O2—H1O2 | 0.74 (3) | C8—C8i | 1.392 (4) |
N1—C7 | 1.317 (2) | C8—C9 | 1.394 (2) |
N1—C8 | 1.422 (2) | C9—C10 | 1.382 (3) |
C1—C2 | 1.399 (2) | C9—H9A | 0.9300 |
C1—C6 | 1.416 (2) | C10—C10i | 1.387 (4) |
C2—C3 | 1.383 (2) | C10—H10A | 0.9300 |
C2—H2A | 0.9300 | O1W—H1W1 | 0.8771 |
C3—C4 | 1.404 (3) | O1W—H2W1 | 0.8309 |
Cg1···Cg4ii | 3.7364 (11) | Cg4···Cg4v | 3.7750 (11) |
Cg2···Cg2ii | 3.7380 (9) | Ni1···O1Wi | 3.7635 (13) |
Cg2···Cg3iii | 3.7381 (9) | O1···O1i | 2.4319 (18) |
Cg3···Cg4iv | 3.5766 (10) | N1···N1i | 2.525 (2) |
O1—Ni1—O1i | 82.53 (8) | C5—C4—H4A | 120.5 |
O1—Ni1—N1i | 174.29 (5) | C3—C4—H4A | 120.5 |
O1i—Ni1—N1i | 95.89 (7) | C4—C5—C6 | 121.82 (17) |
O1—Ni1—N1 | 95.89 (7) | C4—C5—H5A | 119.1 |
O1i—Ni1—N1 | 174.29 (6) | C6—C5—H5A | 119.1 |
N1i—Ni1—N1 | 86.21 (9) | C7—C6—C1 | 123.15 (17) |
C1—O1—Ni1 | 127.44 (11) | C7—C6—C5 | 118.38 (16) |
C3—O2—H1O2 | 111 (2) | C1—C6—C5 | 118.47 (16) |
C7—N1—C8 | 121.12 (15) | N1—C7—C6 | 124.97 (17) |
C7—N1—Ni1 | 125.63 (13) | N1—C7—H7A | 117.5 |
C8—N1—Ni1 | 113.24 (12) | C6—C7—H7A | 117.5 |
O1—C1—C2 | 118.13 (16) | C8i—C8—C9 | 119.92 (11) |
O1—C1—C6 | 122.74 (16) | C8i—C8—N1 | 113.20 (9) |
C2—C1—C6 | 119.12 (17) | C9—C8—N1 | 126.87 (17) |
C3—C2—C1 | 120.89 (17) | C10—C9—C8 | 119.37 (18) |
C3—C2—H2A | 119.6 | C10—C9—H9A | 120.3 |
C1—C2—H2A | 119.6 | C8—C9—H9A | 120.3 |
O2—C3—C2 | 122.42 (17) | C9—C10—C10i | 120.43 (11) |
O2—C3—C4 | 117.00 (16) | C9—C10—H10A | 119.8 |
C2—C3—C4 | 120.59 (17) | C10i—C10—H10A | 119.8 |
C5—C4—C3 | 119.06 (17) | H1W1—O1W—H2W1 | 114.3 |
O1i—Ni1—O1—C1 | −176.47 (18) | O1—C1—C6—C5 | 178.70 (17) |
N1i—Ni1—N1—C7 | −176.59 (19) | C2—C1—C6—C5 | −1.7 (3) |
O1—Ni1—N1—C8 | 177.60 (12) | C4—C5—C6—C7 | −177.71 (18) |
N1i—Ni1—N1—C8 | 2.93 (9) | C4—C5—C6—C1 | 2.4 (3) |
Ni1—O1—C1—C2 | −176.01 (12) | C8—N1—C7—C6 | −175.09 (17) |
Ni1—O1—C1—C6 | 3.6 (3) | Ni1—N1—C7—C6 | 4.4 (3) |
O1—C1—C2—C3 | 179.49 (17) | C1—C6—C7—N1 | −3.0 (3) |
C6—C1—C2—C3 | −0.1 (3) | C5—C6—C7—N1 | 177.10 (18) |
C1—C2—C3—O2 | −178.73 (16) | C7—N1—C8—C8i | 171.2 (2) |
C1—C2—C3—C4 | 1.4 (3) | Ni1—N1—C8—C8i | −8.3 (3) |
O2—C3—C4—C5 | 179.35 (17) | C7—N1—C8—C9 | −7.6 (3) |
C2—C3—C4—C5 | −0.8 (3) | Ni1—N1—C8—C9 | 172.86 (16) |
C3—C4—C5—C6 | −1.1 (3) | C8i—C8—C9—C10 | −5.1 (3) |
O1—C1—C6—C7 | −1.2 (3) | N1—C8—C9—C10 | 173.65 (18) |
C2—C1—C6—C7 | 178.37 (17) | C8—C9—C10—C10i | −1.6 (3) |
Symmetry codes: (i) −x, y, −z+3/2; (ii) −x+1/2, −y+1/2, −z+2; (iii) x+1/2, −y+1/2, z−1/2; (iv) x−1/2, −y+1/2, z−3/2; (v) −x, y, −z+5/2. |
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···O1i | 0.88 | 1.97 | 2.8072 (19) | 160 |
O1W—H2W1···O2vi | 0.83 | 2.17 | 2.9985 (19) | 173 |
C9—H9A···O2vii | 0.93 | 2.60 | 3.394 (2) | 144 |
Symmetry codes: (i) −x, y, −z+3/2; (vi) x, y, z−1; (vii) −x+1/2, y−1/2, −z+5/2. |
Experimental details
Crystal data | |
Chemical formula | [Ni(C20H14N2O4)]·2H2O |
Mr | 441.07 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 100 |
a, b, c (Å) | 10.9049 (2), 17.6602 (3), 9.0375 (3) |
β (°) | 101.150 (1) |
V (Å3) | 1707.61 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.18 |
Crystal size (mm) | 0.35 × 0.12 × 0.11 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2005) |
Tmin, Tmax | 0.683, 0.881 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14574, 3566, 2388 |
Rint | 0.046 |
(sin θ/λ)max (Å−1) | 0.793 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.121, 1.12 |
No. of reflections | 3566 |
No. of parameters | 136 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.61, −0.74 |
Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).
Cg1···Cg4i | 3.7364 (11) | Cg4···Cg4iv | 3.7750 (11) |
Cg2···Cg2i | 3.7380 (9) | Ni1···O1Wv | 3.7635 (13) |
Cg2···Cg3ii | 3.7381 (9) | O1···O1v | 2.4319 (18) |
Cg3···Cg4iii | 3.5766 (10) | N1···N1v | 2.525 (2) |
Symmetry codes: (i) −x+1/2, −y+1/2, −z+2; (ii) x+1/2, −y+1/2, z−1/2; (iii) x−1/2, −y+1/2, z−3/2; (iv) −x, y, −z+5/2; (v) −x, y, −z+3/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W1···O1 | 0.8800 | 2.4000 | 3.0733 (18) | 133.00 |
O1W—H1W1···O1v | 0.8800 | 1.9700 | 2.8072 (19) | 160.00 |
O1W—H2W1···O2vi | 0.8300 | 2.1700 | 2.9985 (19) | 173.00 |
C9—H9A···O2vii | 0.9300 | 2.6000 | 3.394 (2) | 144.00 |
Symmetry codes: (v) −x, y, −z+3/2; (vi) x, y, z−1; (vii) −x+1/2, y−1/2, −z+5/2. |
Acknowledgements
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.
References
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Blower, P. J. (1998). Transition Met. Chem. 23, 109–112. CrossRef CAS Google Scholar
Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Clark, G. R., Hall, D. & Waters, T. N. (1968). J. Chem. Soc. A, pp. 223–226. CSD CrossRef Google Scholar
Clark, G. R., Hall, D. & Waters, T. N. (1969). J. Chem. Soc. A, pp. 823–829. CSD CrossRef Google Scholar
Clark, G. R., Hall, D. & Waters, T. N. (1970). J. Chem. Soc. A, pp. 396–399. Google Scholar
Elmali, A., Elerman, Y. & Svoboda, I. (2000). Acta Cryst. C56, 423–424. CSD CrossRef CAS IUCr Journals Google Scholar
Fun, H.-K. & Kia, R. (2008a). Acta Cryst. E64, m1081–m1082. Web of Science CSD CrossRef IUCr Journals Google Scholar
Fun, H.-K. & Kia, R. (2008b). Acta Cryst. E64, m1116–m1117. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Granovski, A. D., Nivorozhkin, A. L. & Minkin, V. I. (1993). Coord. Chem. Rev. 126, 1–69. Google Scholar
Hodgson, D. J. (1975). Prog. Inorg. Chem. 19, 173–202. CrossRef CAS Google Scholar
Li, C. H. & Chang, T. C. (1991). Eur. Polym. J. 27, 35–39. CrossRef CAS Web of Science Google Scholar
Shahrokhian, S., Amini, M. K., Kia, R. & Tangestaninejad, S. (2000). Anal. Chem. 72, 956–962. Web of Science CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar
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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 NiII 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.