Tetra­aqua­bis(isonicotinamide-κN1)nickel(II) bis­(4-formyl­benzoate) dihydrate

Hökelek, T.; Yılmaz, F.; Tercan, B.; Gürgen, F.; Necefoğlu, H.

doi:10.1107/S1600536809032279

metal-organic compounds

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ISSN: 2056-9890

Volume 65| Part 9| September 2009| Pages m1101-m1102

doi:10.1107/S1600536809032279

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Tetraaquabis(isonicotinamide-κN¹)nickel(II) bis(4-formylbenzoate) dihydrate

Tuncer Hökelek,^a ^* Filiz Yılmaz,^b Barış Tercan,^c Ferdi Gürgen ^d and Hacali Necefoğlu ^d

^aDepartment of Physics, Hacettepe University, 06800 Beytepe, Ankara, Turkey, ^bDepartment of Chemistry, Faculty of Science, Anadolu University, 26470 Yenibağlar, Eskişehir, Turkey, ^cDepartment of Physics, Karabük University, 78050 Karabük, Turkey, and ^dDepartment of Chemistry, Kafkas University, 63100 Kars, Turkey
^*Correspondence e-mail: merzifon@hacettepe.edu.tr

(Received 13 August 2009; accepted 14 August 2009; online 19 August 2009)

The asymmetric unit of the title complex, [Ni(C₆H₆N₂O)₂(H₂O)₄](C₈H₅O₃)₂·2H₂O, contains one-half of the complex cation with the Ni^II atom located on an inversion center, a 4-formylbenzoate (FB) counter-anion and an uncoordinated water molecule. The four O atoms in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement and the slightly distorted octahedral coordination is completed by the two N atoms of the isonicotinamide (INA) ligands at a sligthly longer distance in the axial positions. The dihedral angle between the carboxylate group and the attached benzene ring is 8.14 (11)°, while the pyridine and benzene rings are oriented at a dihedral angle of 3.46 (6)°. In the crystal structure, O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds link the molecules into a three-dimensional network. π–π Contacts between the benzene and pyridine rings [centroid–centroid distance = 3.751 (1) Å] may further stabilize the crystal structure.

Related literature

For general background, see: Bigoli et al. (1972 ); Krishnamachari (1974 ). For related structures, see: Hökelek et al. (2009 ); Sertçelik et al. (2009 ).

Experimental

Crystal data

[Ni(C₆H₆N₂O)₂(H₂O)₄](C₈H₅O₃)₂·2H₂O
M_r = 709.28
Triclinic, $[P \overline 1]$
a = 6.4338 (1) Å
b = 6.9059 (2) Å
c = 18.1649 (3) Å
α = 81.658 (2)°
β = 85.160 (3)°
γ = 71.816 (1)°
V = 758.01 (3) Å³
Z = 1
Mo Kα radiation
μ = 0.72 mm⁻¹
T = 100 K
0.35 × 0.15 × 0.10 mm

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.876, T_max = 0.928
14080 measured reflections
3837 independent reflections
3259 reflections with I > 2σ(I)
R_int = 0.067

Refinement

R[F² > 2σ(F²)] = 0.033
wR(F²) = 0.080
S = 1.01
3837 reflections
250 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.47 e Å⁻³

Table 1
Selected bond lengths (Å)

Ni1—O5	2.0444 (11)
Ni1—O6	2.0857 (11)
Ni1—N1	2.0978 (12)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H21⋯O7ⁱ	0.84 (2)	2.03 (2)	2.8518 (19)	163.7 (17)
N2—H22⋯O3ⁱⁱ	0.879 (19)	2.109 (18)	2.9662 (17)	165.1 (18)
O5—H51⋯O1ⁱⁱⁱ	0.78 (3)	1.87 (2)	2.6485 (16)	177 (3)
O5—H52⋯O2	0.897 (19)	1.847 (19)	2.7349 (16)	169.6 (18)
O6—H61⋯O1^iv	0.87 (3)	1.91 (3)	2.7792 (17)	175 (2)
O6—H62⋯O2^v	0.84 (3)	1.94 (3)	2.7710 (17)	171 (3)
O7—H71⋯O3ⁱⁱⁱ	0.81 (3)	2.11 (3)	2.9260 (19)	176 (2)
O7—H72⋯O4	0.84 (2)	1.90 (2)	2.7333 (18)	174 (2)
C9—H9⋯O7ⁱ	0.93	2.59	3.480 (2)	160
C12—H12⋯O5^vi	0.93	2.44	3.193 (2)	138
Symmetry codes: (i) x-1, y, z; (ii) x+1, y-1, z+1; (iii) -x, -y+1, -z; (iv) x+1, y-1, z; (v) x, y-1, z; (vi) -x+1, -y, -z.

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ) and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809032279/xu2589sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809032279/xu2589Isup2.hkl

checkCIF report

Comment top

As a part of our ongoing investigation on transition metal complexes of nicotinamide (NA), one form of niacin (Krishnamachari, 1974), and/or the nicotinic acid derivative N,N-diethylnicotinamide (DENA), an important respiratory stimulant (Bigoli et al., 1972), the title compound was synthesized and its crystal structure is reported herein.

The title compound is a monomeric complex, with Ni^II ion on a centre of symmetry. The structures of some DENA and/or NA complexes of Ni^II ion, [Ni(C₈H₅O₃)₂(C₁₀H₁₄N₂O)₂(H₂O)₂] (Sertçelik et al., 2009) and [Ni(C₇H₄BrO₂)₂(C₆H₆N₂O)₂(H₂O)₂] (Hökelek et al., 2009) have also been determined.

In the title compound, INA ligands are monodentate. The four O atoms (O5, O6, and the symmetry-related atoms, O5', O6') in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two pyridine N atoms (N1, N1') of the INA ligands at 2.0978 (12) Å from the Ni atom in the axial positions (Table 1, Fig. 1). The average Ni—O bond length is 2.0651 (11) Å. The O—H···O hydrogen bonds (Table 2) link the coordinated and uncoordinated water molecules to the FB anion and INA ligand, respectively. The dihedral angle between the carboxyl group (O1/O2/C1) and the benzene ring A (C2—C7) is 8.14 (11)°, while that between rings A and B (N1/C8—C12) is 3.46 (6)°.

In the crystal structure, the O—H···O, N—H···O and C—H···O hydrogen bonds (Table 2) link the molecules into a three-dimensional network, in which they may be effective in the stabilization of the structure. The π–π contact between the benzene and pyridine rings, Cg1—Cg2, [where Cg1 and Cg2 are centroids of the rings A (C2—C7) and B (N1/C8—C12), respectively] may further stabilize the structure, with centroid-centroid distance of 3.751 (1) Å.

Related literature top

For general background, see: Bigoli et al. (1972); Krishnamachari (1974). For related structures, see: Hökelek et al. (2009); Sertçelik et al. (2009).

Experimental top

The title compound was prepared by the reaction of NiSO₄.6H₂O (1.31 g, 5 mmol) in H₂O (25 ml) and INA (1.22 g, 10 mmol) in H₂O (40 ml) with sodium 4-formylbenzoate (1.72 g, 10 mmol) in H₂O (50 ml). The mixture was filtered and set aside to crystallize at ambient temperature for several days, giving blue single crystals.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top

Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Primed atoms are generated by the symmetry operator:(') -x, -y, -z. Dashed lines indicate the hydrogen bonding.

Tetraaquabis(isonicotinamide-κN¹)nickel(II) bis(4-formylbenzoate) dihydrate top

Crystal data top

[Ni(C₆H₆N₂O)₂(H₂O)₄](C₈H₅O₃)₂·2H₂O	Z = 1
M_r = 709.28	F(000) = 370
Triclinic, P1	D_x = 1.554 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.4338 (1) Å	Cell parameters from 5282 reflections
b = 6.9059 (2) Å	θ = 4.1–28.3°
c = 18.1649 (3) Å	µ = 0.72 mm⁻¹
α = 81.658 (2)°	T = 100 K
β = 85.160 (3)°	Block, blue
γ = 71.816 (1)°	0.35 × 0.15 × 0.1 mm
V = 758.01 (3) Å³

Data collection top

Bruker Kappa APEXII CCD area-detector diffractometer	3837 independent reflections
Radiation source: fine-focus sealed tube	3259 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.067
ϕ and ω scans	θ_max = 28.5°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −8→8
T_min = 0.876, T_max = 0.928	k = −9→9
14080 measured reflections	l = −24→24

Refinement top

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)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.080	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	w = 1/[σ²(F_o²) + (0.0396P)²] where P = (F_o² + 2F_c²)/3
3837 reflections	(Δ/σ)_max < 0.001
250 parameters	Δρ_max = 0.50 e Å⁻³
0 restraints	Δρ_min = −0.47 e Å⁻³

Crystal data top

[Ni(C₆H₆N₂O)₂(H₂O)₄](C₈H₅O₃)₂·2H₂O	γ = 71.816 (1)°
M_r = 709.28	V = 758.01 (3) Å³
Triclinic, P1	Z = 1
a = 6.4338 (1) Å	Mo Kα radiation
b = 6.9059 (2) Å	µ = 0.72 mm⁻¹
c = 18.1649 (3) Å	T = 100 K
α = 81.658 (2)°	0.35 × 0.15 × 0.1 mm
β = 85.160 (3)°

Data collection top

Bruker Kappa APEXII CCD area-detector diffractometer	3837 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	3259 reflections with I > 2σ(I)
T_min = 0.876, T_max = 0.928	R_int = 0.067
14080 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.033	0 restraints
wR(F²) = 0.080	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	Δρ_max = 0.50 e Å⁻³
3837 reflections	Δρ_min = −0.47 e Å⁻³
250 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ni1	0.0000	0.0000	0.0000	0.00952 (9)
O1	−0.32770 (17)	0.69399 (18)	−0.08791 (6)	0.0156 (2)
O2	0.02696 (17)	0.55211 (17)	−0.11784 (6)	0.0147 (2)
O3	−0.5543 (2)	0.7444 (2)	−0.46465 (6)	0.0248 (3)
O4	0.62907 (18)	−0.23630 (19)	0.31701 (6)	0.0187 (3)
O5	0.18852 (18)	0.19178 (18)	−0.02699 (6)	0.0121 (2)
H51	0.228 (4)	0.229 (4)	0.0063 (13)	0.050 (8)*
H52	0.124 (3)	0.303 (3)	−0.0585 (10)	0.027 (5)*
O6	0.23596 (19)	−0.24606 (18)	−0.04216 (6)	0.0143 (2)
H61	0.370 (4)	−0.265 (4)	−0.0591 (12)	0.048 (7)*
H62	0.181 (4)	−0.320 (4)	−0.0624 (12)	0.040 (7)*
O7	0.8514 (2)	−0.1254 (2)	0.41718 (7)	0.0214 (3)
H71	0.771 (4)	−0.021 (4)	0.4322 (13)	0.055 (9)*
H72	0.775 (3)	−0.155 (3)	0.3879 (12)	0.037 (6)*
N1	0.1326 (2)	−0.0939 (2)	0.10564 (7)	0.0112 (3)
N2	0.3028 (2)	−0.1740 (2)	0.37981 (7)	0.0153 (3)
H21	0.166 (3)	−0.153 (3)	0.3816 (10)	0.024 (5)*
H22	0.369 (3)	−0.199 (3)	0.4221 (10)	0.021 (5)*
C1	−0.1722 (2)	0.6250 (2)	−0.13329 (8)	0.0129 (3)
C2	−0.2270 (2)	0.6334 (2)	−0.21321 (8)	0.0120 (3)
C3	−0.4455 (2)	0.6912 (2)	−0.23337 (8)	0.0130 (3)
H3	−0.5580	0.7218	−0.1972	0.016*
C4	−0.4939 (3)	0.7027 (3)	−0.30658 (8)	0.0149 (3)
H4	−0.6391	0.7411	−0.3198	0.018*
C5	−0.3256 (3)	0.6570 (3)	−0.36097 (8)	0.0142 (3)
C6	−0.1081 (3)	0.5964 (3)	−0.34101 (8)	0.0159 (3)
H6	0.0043	0.5631	−0.3771	0.019*
C7	−0.0597 (3)	0.5859 (3)	−0.26751 (8)	0.0144 (3)
H7	0.0855	0.5468	−0.2543	0.017*
C8	0.0066 (2)	−0.0685 (2)	0.16870 (8)	0.0119 (3)
H8	−0.1447	−0.0268	0.1651	0.014*
C9	0.0914 (2)	−0.1014 (2)	0.23847 (8)	0.0126 (3)
H9	−0.0017	−0.0812	0.2806	0.015*
C10	0.3172 (2)	−0.1649 (2)	0.24511 (8)	0.0109 (3)
C11	0.4476 (2)	−0.1990 (3)	0.18050 (8)	0.0133 (3)
H11	0.5993	−0.2465	0.1828	0.016*
C12	0.3506 (2)	−0.1620 (3)	0.11290 (8)	0.0139 (3)
H12	0.4406	−0.1854	0.0702	0.017*
C13	0.4277 (3)	−0.1948 (2)	0.31741 (8)	0.0130 (3)
C14	−0.3734 (3)	0.6682 (3)	−0.43942 (9)	0.0197 (4)
H14	−0.245 (3)	0.614 (3)	−0.4731 (10)	0.021 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.00852 (14)	0.01296 (17)	0.00766 (14)	−0.00363 (11)	−0.00026 (10)	−0.00235 (11)
O1	0.0131 (5)	0.0221 (7)	0.0133 (5)	−0.0060 (5)	0.0003 (4)	−0.0068 (5)
O2	0.0121 (5)	0.0168 (6)	0.0160 (5)	−0.0042 (5)	−0.0035 (4)	−0.0032 (5)
O3	0.0253 (7)	0.0314 (8)	0.0150 (6)	−0.0030 (6)	−0.0067 (5)	−0.0039 (5)
O4	0.0123 (6)	0.0267 (7)	0.0168 (5)	−0.0033 (5)	−0.0039 (4)	−0.0063 (5)
O5	0.0122 (5)	0.0151 (6)	0.0101 (5)	−0.0055 (5)	−0.0011 (4)	−0.0017 (5)
O6	0.0111 (6)	0.0176 (6)	0.0159 (5)	−0.0048 (5)	0.0010 (4)	−0.0072 (5)
O7	0.0168 (6)	0.0307 (8)	0.0180 (6)	−0.0065 (6)	−0.0018 (5)	−0.0082 (6)
N1	0.0110 (6)	0.0121 (7)	0.0110 (6)	−0.0038 (5)	0.0009 (5)	−0.0034 (5)
N2	0.0139 (7)	0.0222 (8)	0.0098 (6)	−0.0043 (6)	−0.0040 (5)	−0.0028 (6)
C1	0.0153 (8)	0.0106 (8)	0.0149 (7)	−0.0060 (7)	−0.0018 (6)	−0.0024 (6)
C2	0.0139 (7)	0.0094 (8)	0.0138 (7)	−0.0047 (6)	−0.0022 (6)	−0.0022 (6)
C3	0.0123 (7)	0.0128 (8)	0.0133 (7)	−0.0025 (6)	0.0002 (6)	−0.0028 (6)
C4	0.0134 (7)	0.0157 (9)	0.0151 (7)	−0.0028 (7)	−0.0028 (6)	−0.0023 (7)
C5	0.0180 (8)	0.0136 (8)	0.0118 (7)	−0.0056 (7)	−0.0020 (6)	−0.0017 (6)
C6	0.0167 (8)	0.0157 (9)	0.0143 (7)	−0.0035 (7)	0.0026 (6)	−0.0035 (7)
C7	0.0127 (7)	0.0126 (8)	0.0174 (7)	−0.0029 (6)	−0.0017 (6)	−0.0019 (7)
C8	0.0097 (7)	0.0135 (8)	0.0126 (7)	−0.0034 (6)	−0.0007 (5)	−0.0019 (6)
C9	0.0127 (7)	0.0142 (8)	0.0105 (7)	−0.0038 (6)	0.0009 (6)	−0.0022 (6)
C10	0.0129 (7)	0.0085 (8)	0.0117 (7)	−0.0033 (6)	−0.0019 (6)	−0.0021 (6)
C11	0.0103 (7)	0.0149 (8)	0.0146 (7)	−0.0037 (6)	−0.0008 (6)	−0.0021 (6)
C12	0.0113 (7)	0.0172 (9)	0.0125 (7)	−0.0033 (7)	0.0018 (6)	−0.0033 (6)
C13	0.0148 (8)	0.0105 (8)	0.0137 (7)	−0.0026 (6)	−0.0030 (6)	−0.0027 (6)
C14	0.0242 (9)	0.0203 (10)	0.0133 (7)	−0.0047 (8)	0.0008 (7)	−0.0033 (7)

Geometric parameters (Å, º) top

Ni1—O5	2.0444 (11)	C2—C7	1.391 (2)
Ni1—O5ⁱ	2.0444 (11)	C3—C2	1.401 (2)
Ni1—O6	2.0857 (11)	C3—C4	1.377 (2)
Ni1—O6ⁱ	2.0857 (11)	C3—H3	0.9300
Ni1—N1	2.0978 (12)	C4—H4	0.9300
Ni1—N1ⁱ	2.0978 (12)	C5—C4	1.395 (2)
O1—C1	1.2587 (18)	C5—C6	1.393 (2)
O2—C1	1.2616 (18)	C5—C14	1.469 (2)
O3—C14	1.216 (2)	C6—C7	1.383 (2)
O4—C13	1.2359 (18)	C6—H6	0.9300
O5—H51	0.78 (2)	C7—H7	0.9300
O5—H52	0.90 (2)	C8—H8	0.9300
O6—H61	0.86 (2)	C9—C8	1.382 (2)
O6—H62	0.84 (2)	C9—C10	1.391 (2)
O7—H71	0.82 (3)	C9—H9	0.9300
O7—H72	0.84 (2)	C10—C11	1.388 (2)
N1—C8	1.3465 (18)	C10—C13	1.503 (2)
N1—C12	1.3444 (19)	C11—C12	1.379 (2)
N2—C13	1.3316 (19)	C11—H11	0.9300
N2—H21	0.84 (2)	C12—H12	0.9300
N2—H22	0.879 (19)	C14—H14	0.991 (18)
C2—C1	1.511 (2)

O5ⁱ—Ni1—O5	180.00 (6)	C4—C3—C2	120.18 (14)
O5—Ni1—O6	92.91 (5)	C4—C3—H3	119.9
O5ⁱ—Ni1—O6	87.09 (5)	C3—C4—C5	120.09 (14)
O5—Ni1—O6ⁱ	87.09 (5)	C3—C4—H4	120.0
O5ⁱ—Ni1—O6ⁱ	92.91 (5)	C5—C4—H4	120.0
O5—Ni1—N1	91.09 (5)	C4—C5—C6	119.94 (14)
O5ⁱ—Ni1—N1	88.91 (5)	C4—C5—C14	121.06 (14)
O5—Ni1—N1ⁱ	88.91 (5)	C6—C5—C14	119.00 (14)
O5ⁱ—Ni1—N1ⁱ	91.09 (5)	C5—C6—H6	120.1
O6—Ni1—O6ⁱ	180.00 (8)	C7—C6—C5	119.89 (14)
O6—Ni1—N1	90.55 (5)	C7—C6—H6	120.1
O6ⁱ—Ni1—N1	89.45 (5)	C2—C7—H7	119.8
O6—Ni1—N1ⁱ	89.45 (5)	C6—C7—C2	120.35 (14)
O6ⁱ—Ni1—N1ⁱ	90.55 (5)	C6—C7—H7	119.8
N1—Ni1—N1ⁱ	180.00 (3)	N1—C8—C9	123.15 (14)
Ni1—O5—H51	116.0 (17)	N1—C8—H8	118.4
Ni1—O5—H52	112.8 (12)	C9—C8—H8	118.4
H52—O5—H51	108 (2)	C8—C9—C10	119.38 (13)
Ni1—O6—H61	133.3 (16)	C8—C9—H9	120.3
Ni1—O6—H62	112.7 (15)	C10—C9—H9	120.3
H61—O6—H62	109 (2)	C9—C10—C13	124.09 (13)
H71—O7—H72	104 (2)	C11—C10—C9	117.58 (13)
C8—N1—Ni1	121.97 (10)	C11—C10—C13	118.32 (13)
C12—N1—Ni1	120.69 (9)	C10—C11—H11	120.2
C12—N1—C8	116.97 (13)	C12—C11—C10	119.56 (14)
C13—N2—H21	124.0 (12)	C12—C11—H11	120.2
C13—N2—H22	117.6 (12)	N1—C12—C11	123.27 (13)
H21—N2—H22	118.0 (17)	N1—C12—H12	118.4
O1—C1—O2	125.32 (14)	C11—C12—H12	118.4
O1—C1—C2	117.63 (14)	O4—C13—N2	122.48 (14)
O2—C1—C2	117.04 (13)	O4—C13—C10	119.41 (13)
C3—C2—C1	120.57 (13)	N2—C13—C10	118.11 (13)
C7—C2—C1	119.88 (14)	O3—C14—C5	124.44 (15)
C7—C2—C3	119.54 (14)	O3—C14—H14	119.8 (10)
C2—C3—H3	119.9	C5—C14—H14	115.7 (10)

O5—Ni1—N1—C8	120.80 (12)	C4—C3—C2—C7	−0.6 (2)
O5ⁱ—Ni1—N1—C8	−59.20 (12)	C2—C3—C4—C5	0.0 (2)
O5—Ni1—N1—C12	−51.98 (12)	C6—C5—C4—C3	1.0 (2)
O5ⁱ—Ni1—N1—C12	128.02 (12)	C14—C5—C4—C3	179.97 (15)
O6—Ni1—N1—C8	−146.28 (12)	C4—C5—C6—C7	−1.3 (2)
O6ⁱ—Ni1—N1—C8	33.72 (12)	C14—C5—C6—C7	179.69 (15)
O6—Ni1—N1—C12	40.95 (12)	C4—C5—C14—O3	11.3 (3)
O6ⁱ—Ni1—N1—C12	−139.05 (12)	C6—C5—C14—O3	−169.77 (17)
Ni1—N1—C8—C9	−170.46 (12)	C5—C6—C7—C2	0.7 (2)
C12—N1—C8—C9	2.6 (2)	C10—C9—C8—N1	−0.4 (2)
Ni1—N1—C12—C11	170.82 (12)	C8—C9—C10—C11	−2.1 (2)
C8—N1—C12—C11	−2.3 (2)	C8—C9—C10—C13	176.67 (14)
C3—C2—C1—O1	−8.1 (2)	C9—C10—C11—C12	2.4 (2)
C3—C2—C1—O2	173.07 (14)	C13—C10—C11—C12	−176.49 (14)
C7—C2—C1—O1	171.16 (14)	C9—C10—C13—O4	−174.45 (15)
C7—C2—C1—O2	−7.7 (2)	C9—C10—C13—N2	5.2 (2)
C1—C2—C7—C6	−178.93 (14)	C11—C10—C13—O4	4.3 (2)
C3—C2—C7—C6	0.3 (2)	C11—C10—C13—N2	−176.04 (15)
C4—C3—C2—C1	178.61 (14)	C10—C11—C12—N1	−0.2 (2)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···O7ⁱⁱ	0.84 (2)	2.03 (2)	2.8518 (19)	163.7 (17)
N2—H22···O3ⁱⁱⁱ	0.879 (19)	2.109 (18)	2.9662 (17)	165.1 (18)
O5—H51···O1^iv	0.78 (3)	1.87 (2)	2.6485 (16)	177 (3)
O5—H52···O2	0.897 (19)	1.847 (19)	2.7349 (16)	169.6 (18)
O6—H61···O1^v	0.87 (3)	1.91 (3)	2.7792 (17)	175 (2)
O6—H62···O2^vi	0.84 (3)	1.94 (3)	2.7710 (17)	171 (3)
O7—H71···O3^iv	0.81 (3)	2.11 (3)	2.9260 (19)	176 (2)
O7—H72···O4	0.84 (2)	1.90 (2)	2.7333 (18)	174 (2)
C9—H9···O7ⁱⁱ	0.93	2.59	3.480 (2)	160
C12—H12···O5^vii	0.93	2.44	3.193 (2)	138

Symmetry codes: (ii) x−1, y, z; (iii) x+1, y−1, z+1; (iv) −x, −y+1, −z; (v) x+1, y−1, z; (vi) x, y−1, z; (vii) −x+1, −y, −z.

Experimental details

Crystal data
Chemical formula	[Ni(C₆H₆N₂O)₂(H₂O)₄](C₈H₅O₃)₂·2H₂O
M_r	709.28
Crystal system, space group	Triclinic, P1
Temperature (K)	100
a, b, c (Å)	6.4338 (1), 6.9059 (2), 18.1649 (3)
α, β, γ (°)	81.658 (2), 85.160 (3), 71.816 (1)
V (Å³)	758.01 (3)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	0.72
Crystal size (mm)	0.35 × 0.15 × 0.1

Data collection
Diffractometer	Bruker Kappa APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.876, 0.928
No. of measured, independent and observed [I > 2σ(I)] reflections	14080, 3837, 3259
R_int	0.067
(sin θ/λ)_max (Å⁻¹)	0.671

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.033, 0.080, 1.01
No. of reflections	3837
No. of parameters	250
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.50, −0.47

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Selected bond lengths (Å) top

Ni1—O5	2.0444 (11)	Ni1—N1	2.0978 (12)
Ni1—O6	2.0857 (11)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···O7ⁱ	0.84 (2)	2.03 (2)	2.8518 (19)	163.7 (17)
N2—H22···O3ⁱⁱ	0.879 (19)	2.109 (18)	2.9662 (17)	165.1 (18)
O5—H51···O1ⁱⁱⁱ	0.78 (3)	1.87 (2)	2.6485 (16)	177 (3)
O5—H52···O2	0.897 (19)	1.847 (19)	2.7349 (16)	169.6 (18)
O6—H61···O1^iv	0.87 (3)	1.91 (3)	2.7792 (17)	175 (2)
O6—H62···O2^v	0.84 (3)	1.94 (3)	2.7710 (17)	171 (3)
O7—H71···O3ⁱⁱⁱ	0.81 (3)	2.11 (3)	2.9260 (19)	176 (2)
O7—H72···O4	0.84 (2)	1.90 (2)	2.7333 (18)	174 (2)
C9—H9···O7ⁱ	0.93	2.59	3.480 (2)	160.00
C12—H12···O5^vi	0.93	2.44	3.193 (2)	138.00

Symmetry codes: (i) x−1, y, z; (ii) x+1, y−1, z+1; (iii) −x, −y+1, −z; (iv) x+1, y−1, z; (v) x, y−1, z; (vi) −x+1, −y, −z.

Acknowledgements

The authors are indebted to Anadolu University and the Medicinal Plants and Medicine Research Centre of Anadolu University, Eskişehir, Turkey, for the use of the X-ray diffractometer. This work was supported financially by Kafkas University Research Fund (grant No. 2009-FEF-03).

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