Two mononuclear octa­hedral complexes with benzimidazole-2-carboxyl­ate: supra­molecular networks constructed by hydrogen bonds

The title compounds, trans-bis­(1H-benzimidazole-2-carbox­ylato-[kappa]²N³,O)bis­(ethanol-[kappa]O)cadmium(II), [Cd(C₈H₅N₂O₂)₂(C₂H₆O)₂], (I), and trans-bis­(1H-benzimidazole-[kappa]N³)bis­(1H-benzimidazole-2-carboxyl­ato-[kappa]²N³,O)nickel(II), [Ni(C₈H₅N₂O₂)₂(C₇H₆N₂)₂], (II), are hydrogen-bonded supra­molecular complexes. In (I), the Cd^II ion is six-coordinated by two O atoms from two ethanol mol­ecules, and by two O and two N atoms from two bidentate benzimidazole-2-carboxyl­ate (HBIC) ligands, giving a distorted octa­hedral geometry. The combination of O-H...O and N-H...O hydrogen bonds results in two-dimensional layers parallel to the ab plane. In (II), the six-coordinated Ni^II atom, which lies on an inversion centre, shows a similar distorted octa­hedral geometry to the Cd^II ion in (I); two benzimidazole mol­ecules occupy the axial sites and the equatorial plane contains two chelating HBIC ligands. Pairs of N-H...O hydrogen bonds between pairs of HBIC anions connect adjacent Ni^II coordination units to form a one-dimensional chain parallel to the a axis. Moreover, these one-dimensional chains are further linked via N-H...O hydrogen bonds between HBIC anions and benzimidazole mol­ecules to generate a three-dimensional supra­molecular framework. The two compounds show quite different supra­molecular networks, which may be explained by the fact that different co-ligands occupy the axial sites in the coordination units.

S1. Comment

The design and construction of coordination architectures with unprecedented topologies have attracted considerable attention over recent decades (Moulton & Zaworotko, 2001; Roesky & Andruh, 2003). Discrete coordination assemblies are linked through numerous weak interactions, such as hydrogen bonds and π–π stacking, thereby resulting in higher-dimensional supramolecular networks with multiple structural features and properties (Kitaura et al., 2003; Custelcean et al., 2006; Madalan et al., 2006; Jiang et al., 2008, 2009). It has been demonstrated that the number and orientation of weak attraction sites on the discrete building blocks have a significant effect on the resulting supramolecular structures. Thus, minor changes in interaction sites in the building blocks may affect the packing and even the overall network. Related studies will help us rationally design crystallized materials with desirable structures.

Assembly of the complexes based on bis(chelating) bridging ligands has been of intense interest, mainly because of the multiple coordination modes of these ligands, intriguing structural features and potential properties of the resulting complexes (Zhang, Cheng et al., 2008; Zhang, Ma et al., 2008; Colacio et al., 2009; Mota et al., 2010). For example, a great many magnetically ordered materials based on oxalate and its derivatives have been explored in recent years (Ruiz et al., 1999; Xu et al., 2007; Train et al., 2008). Benzimidazole-2-carboxylic acid (H₂BIC) represents a new kind of bis(chelating) bridging ligand and is less well explored than oxalate and its derivatives. Until now, several complexes constructed from H₂BIC molecules have been investigated, and they exhibited low-dimensional structural features, such as mononuclear, discrete six-membered rings and a two-dimensional honeycomb network containing bowl-shaped voids (Dutta & Satapathi, 1981; Rettig et al., 1999; Saczewski et al., 2006; Zheng et al., 2011). In this work, we present the structures and supramolecular assembly via hydrogen bonds of two new complexes with H₂BIC ligands, namely, trans-bis(1H-benzimidazole-2-carboxylato-κ²N³,O)bis(ethanol-κO)cadmium, (I), and trans-bis(1H-benzimidazole-2-carboxylato-κ²N³,O)bis(1H-benzimidazole-κN³)nickel(II), (II). Both possess similar mononuclear structures and one-dimensional hydrogen-bonding chains, but different hydrogen bonds involving the group on the axial sites result in quite different higher-dimensional networks.

The molecule of complex (I) consists of one Cd^II ion, two HBIC anions (HBIC is benzimidazole-2-carboxylate) and two ligated ethanol molecules (Fig. 1), while in complex (II), the asymmetric unit only contains half a Ni^II ion, one HBIC anion and one benzimidazole molecule as the Ni^II ion lies on a crystallographic inversion centre (Fig. 2). (I) and (II) are mononuclear complexes, in which the metal centre displays a distorted octahedral coordination geometry completed by two N atoms and two O atoms from two bidentate chelating HBIC ligands in the equatorial plane, and two donors from the different coligands in axial sites [O atoms from two ethanol molecules in (I) and N atoms from two benzimidazole molecules in (II)]. Selected bond lengths and angles for the title compounds are listed in Table 1 and the M—O and M—N bond distances [M = Cd in (I) and Ni in (II)] are in the normal ranges (Sarma et al., 2009; Yang & Wu, 2009). In (I), two trans-oriented HBIC ligands at the equatorial positions are almost coplanar, with a dihedral angle between the Cd1/N1/O1 and Cd1/N3/O3 planes of 9.97°. Two ligated ethanol molecules occupy the axial sites and the axial O5—Cd1—O6 angle [179.94 (19)°] deviates only slightly from 180°. In (II), two HBIC anions also occupy the equatorial plane, forming five-membered chelate rings and the dihedral angle between the Ni1/N1/O1 and Ni1/N1ⁱ/O1ⁱ planes [symmetry code: (i) -x+2, -y, -z] is 0°.

In the title compounds, pairs of N—H···O hydrogen bonds are formed between pairs of HBIC anions from adjacent mononuclear building blocks [N2—H2···O4ⁱⁱ and N4—H4···O2ⁱⁱⁱ, symmetry codes: (ii) x+1, y-1, z; (iii) x-1, y+1, z for (I); N2—H2···O2^iv, symmetry code: (iv) -x+1, -y, -z for (II)], which yield centrosymmetric R₂²(10) rings. Thus, the connection of these hydrogen bonds leads to similar one-dimensional chain-like structures in both complexes (Fig. 3). However, further investigation indicates that these one-dimensional chains are arranged in a quite different manner through the linkage of intermolecular attractions, thereby resulting in quite different supramolecular frameworks, mainly due to the difference in the apical ligand of the metal centres.

In compound (I), two ligated ethanol molecules act as hydrogen-bond donors to form two hydrogen bonds with carboxylate O atoms (O1 and O3) of HBIC ligands from adjacent one-dimensional chains. The angle between the ethanol O—H group and the equatorial plane is 81.027° and this orientation of the hydrogen-bond donor favours the formation of a ring. Thus, intermolecular O5—H5···O3^v and O6—H6···O1^vi hydrogen bonds between adjacent mononuclear building units [symmetry codes: (v) x+1, y, z; (vi) x-1, y, z], which generate R₂²(8) rings, serve to further link the one-dimensional chains into an extended two-dimensional supramolecular layer, which runs along the ab plane (Fig. 4). In the structure of (I), all potential strong hydrogen-bonding sites are involved in the formation of hydrogen bonds in the two-dimensional supramolecular network.

In compound (II), benzimidazole molecules occupying the axial sites also act as hydrogen-bond donors to generate N4—H4···O1^vii hydrogen bonds [symmetry code: (vii) -x+2, y+1/2, -z+1/2], with carboxylate O atoms (O2) of HBIC anions. Although the angle between the benzimidazole N—H group and the equatorial plane is 44.891° and the orientation of the hydrogen-bond donor in (II) is not suitable for the formation of a hydrogen-bond ring, these hydrogen-bond interaction sites cannot be restrained in a two-dimensional layer, thereby resulting in a three-dimensional supramolecular network (Fig. 5).

The topological analysis approach was employed to better describe the structural characteristics of (II). The topology of this three-dimensional supramolecular framework can be simplified by considering the Ni^II coordination units as six-connected nodes and the intermolecular hydrogen bonds as two-connected linkers between these nodes. As a result, a three-dimensional network structure of 4¹².6³-pcu topology is formed.

IR spectra of the two compounds show characteristic absorptions for the carboxylate stretching vibrations. The characteristic bands of carboxylate groups are seen in the range 1648–1520 cm^-1 for asymmetric stretching and 1490–1458 cm^-1 for symmetric stretching (Zheng et al., 2011). The absence of strong absorption peaks around 1700 cm^-1 indicates that all carboxyl groups (–COOH) are deprotonated. Moreover, a strong and broad absorption band at 3587 cm^-1 is assigned to the ν(O—H) vibration of ethanol molecules in complex (I).

In summary, two new complexes were constructed from the reaction between various metal salts and H₂BIC molecules with different coligands. They show a similar mononuclear structure, where the metal ions reside in a distorted octahedral coordination environment and in which two bidentate chelating HBIC anions exist in the equatorial positions. However, intermolecular hydrogen bonds link discrete coordination units to form different supramolecular networks.

Related literature

For general background, see: Jiang, et al. (2008); Jiang, et al. (2009); Kitaura, et al. (2003); Madalan, et al. (2006); Moulton & Zaworotko, (2001); Roesky & Andruh, (2003); For related compounds, see: Dutta, et al. (1981); Rettig, et al. (1999); Saczewski, et al. (2006); Zheng et al.(2011).

S2. Experimental

For the synthesis of complex (I), benzimidazole-2-carboxylic acid (H₂BIC, 16.2 mg, 0.10 mmol) was dissolved in water (5 ml) and the pH was adjusted to about 8 with NaOH solution. A solution of Cd(ClO₄)₂.6H₂O (41.9 mg, 0.10 mmol) in ethanol (5 ml) was then layered on the aqueous H₂BIC solution. The system was left for about 2 months at room temperature and colourless block-shaped crystals of (I) were obtained by filtration (yield 56%). IR (KBr pellet, ν, cm^-1): 3587 (s), 3100 (s), 1648 (s), 1582 (w), 1520 (s), 1484 (m), 1458 (s), 1391 (m), 1331 (s), 1212 (w), 1147 (w), 1018 (s), 994 (w), 948 (w), 911 (w), 857 (m), 819 (m), 757 (s), 631 (w), 593 (w), 547 (w), 436 (w).

For the preparation of (II), a mixture of NiCl₂.6H₂O (23.8 mg, 0.10 mmol), H₂BIC (16.2 mg, 0.10 mmol) and benzimidazole (11.8 mg, 0.10 mmol) in H₂O–C₂H₅OH (3:1v/v, 4 ml) was sealed in a sample bottle reactor (10 ml), and heated at 383 K under autogenous pressure for 48 h. After the sample was cooled to room temperature at a rate of 5 K h^-1, block-shaped pale-purple crystals of (II) were collected (yield, 68%). IR (KBr pellet, ν, cm^-1): 3098 (s), 1627 (s), 1614 (s), 1523 (m), 1490 (m), 1464 (s), 1391 (s), 1372 (w), 1343 (s), 1302 (w), 1273 (w), 1145 (w), 1023 (m), 966 (w), 914 (w), 858 (w), 823 (m), 766 (w), 743 (s), 637 (w), 597 (w), 433 (w).

S3. Refinement

A SIMU instruction (SHELXL97; Sheldrick, 2008) was used for several C atoms with large displacement parameters in the refinement of both structures. H atoms of the ethanol molecules were located in difference Fourier maps and the others were placed in calculated positions and refined as riding atoms, with isotropic displacement parameters [C—H = 0.97 Å (methyl), 0.96 Å (methylene) and 0.93 Å (aromatic), and N—H = 0.86 Å; U_iso(H) = 1.2U_eq(C), 1.2U_eq(N) and 1.5U_eq(O)].

Computing details

For both compounds, data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Bruker, 2004); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are shown at the 30% probability level. All H atoms are drawn as spheres of arbitrary radii.
	Fig. 2. The molecular structure of (II), with displacement ellipsoids at the 30% probability level. [Symmetry code: (i) -x+2, -y, -z.]
	Fig. 3. (a) A packing diagram of (I), showing a one-dimensional chain formed by pairs of intermolecular hydrogen bonds (dashed lines). (b) A packing diagram of (II), showing a one-dimensional chain. Dashed lines represent N—H···O interactions.
	Fig. 4. A packing diagram of (I), showing the two-dimensional layer-like structure along the ab plane. Dashed lines represent hydrogen-bonding interactions.
	Fig. 5. A packing diagram of (II), showing the three-dimensional supramolecular network formed by intermolecular hydrogen bonds (dashed lines).

(I) trans-bis(1H-benzimidazole-2-carboxylato- κ²N³,O)bis(ethanol-κO)cadmium

Crystal data

[Cd(C8H5N2O2)2(C2H6O)2]	Z = 2
Mr = 526.82	F(000) = 532
Triclinic, P1	Dx = 1.617 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.4761 (11) Å	Cell parameters from 3684 reflections
b = 10.477 (2) Å	θ = 2.1–28.0°
c = 19.896 (4) Å	µ = 1.05 mm^−1
α = 75.31 (3)°	T = 298 K
β = 88.67 (3)°	Block, colorless
γ = 78.54 (3)°	0.35 × 0.28 × 0.22 mm
V = 1081.7 (4) Å^3

Data collection

Bruker SMART APEXII CCD area-detector diffractometer	3804 independent reflections
Radiation source: fine-focus sealed tube	3228 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
ϕ and ω scans	θmax = 25.3°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −6→6
Tmin = 0.709, Tmax = 0.801	k = −8→12
5344 measured reflections	l = −23→23

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.161	H-atom parameters constrained
S = 1.17	w = 1/[σ^2(Fo^2) + (0.091P)^2 + 0.8152P] where P = (Fo^2 + 2Fc^2)/3
3804 reflections	(Δ/σ)max < 0.001
270 parameters	Δρmax = 0.93 e Å^−3
12 restraints	Δρmin = −1.26 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	1.3408 (11)	0.3004 (6)	0.2742 (3)	0.0332 (14)
C2	1.1412 (11)	0.2866 (6)	0.2266 (3)	0.0331 (14)
C3	0.8147 (11)	0.3459 (6)	0.1589 (3)	0.0328 (14)
C4	0.5996 (13)	0.4078 (7)	0.1185 (4)	0.0416 (16)
H4	0.5264	0.4972	0.1154	0.050*
C5	0.4981 (14)	0.3328 (8)	0.0831 (4)	0.0512 (19)
H5	0.3554	0.3725	0.0553	0.061*
C6	0.6057 (14)	0.1984 (8)	0.0884 (4)	0.0522 (19)
H6	0.5312	0.1504	0.0641	0.063*
C7	0.8173 (14)	0.1340 (7)	0.1279 (4)	0.0456 (17)
H7	0.8874	0.0440	0.1314	0.055*
C8	0.9204 (11)	0.2111 (6)	0.1624 (3)	0.0317 (13)
C9	0.5649 (11)	0.8315 (5)	0.2267 (3)	0.0306 (10)
C10	0.7642 (11)	0.8349 (5)	0.2746 (3)	0.0306 (10)
C11	0.9695 (12)	0.9084 (6)	0.3467 (3)	0.0362 (14)
C12	1.0590 (15)	0.9781 (8)	0.3879 (4)	0.0528 (19)
H12	0.9762	1.0633	0.3904	0.063*
C13	1.2764 (16)	0.9149 (9)	0.4251 (4)	0.064 (2)
H13	1.3421	0.9586	0.4536	0.077*
C14	1.4025 (14)	0.7869 (9)	0.4217 (4)	0.055 (2)
H14	1.5510	0.7481	0.4471	0.066*
C15	1.3104 (13)	0.7175 (7)	0.3814 (4)	0.0451 (17)
H15	1.3931	0.6321	0.3792	0.054*
C16	1.0885 (11)	0.7799 (6)	0.3437 (3)	0.0320 (13)
C17	1.114 (2)	0.7606 (15)	0.0884 (5)	0.106 (3)
H17A	1.2627	0.7592	0.0610	0.127*
H17B	1.0551	0.8525	0.0916	0.127*
C18	0.933 (2)	0.7243 (14)	0.0534 (5)	0.106 (3)
H18A	0.8211	0.6842	0.0863	0.158*
H18B	1.0107	0.6608	0.0283	0.158*
H18C	0.8405	0.8030	0.0214	0.158*
C19	0.803 (2)	0.3672 (13)	0.4042 (5)	0.102 (4)
H19A	0.6588	0.3763	0.4331	0.122*
H19B	0.8334	0.2764	0.3982	0.122*
C20	1.002 (2)	0.3785 (16)	0.4404 (5)	0.121 (4)
H20A	1.0637	0.2944	0.4734	0.181*
H20B	0.9516	0.4478	0.4644	0.181*
H20C	1.1310	0.4014	0.4088	0.181*
Cd1	0.96009 (8)	0.56762 (4)	0.24707 (2)	0.0340 (2)
N1	0.9573 (9)	0.3935 (5)	0.2001 (3)	0.0306 (11)
N2	1.1252 (10)	0.1804 (5)	0.2066 (3)	0.0338 (12)
H2	1.2255	0.1036	0.2189	0.041*
N3	0.9557 (9)	0.7379 (4)	0.2984 (2)	0.0276 (11)
N4	0.7641 (10)	0.9422 (5)	0.3027 (3)	0.0372 (12)
H4A	0.6558	1.0164	0.2943	0.045*
O1	1.3254 (7)	0.4140 (4)	0.2869 (2)	0.0389 (11)
O2	1.5031 (9)	0.1989 (4)	0.2973 (3)	0.0449 (12)
O3	0.5918 (8)	0.7217 (4)	0.2081 (2)	0.0367 (10)
O4	0.3923 (8)	0.9285 (5)	0.2086 (3)	0.0488 (12)
O5	1.1789 (9)	0.6796 (5)	0.1549 (2)	0.0505 (13)
H5A	1.2842	0.6807	0.1853	0.076*
O6	0.7399 (9)	0.4546 (5)	0.3399 (2)	0.0466 (12)
H6A	0.6272	0.4348	0.3183	0.070*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.034 (3)	0.027 (3)	0.043 (4)	−0.005 (3)	−0.001 (3)	−0.017 (3)
C2	0.038 (3)	0.035 (3)	0.032 (3)	−0.003 (3)	0.004 (3)	−0.023 (3)
C3	0.032 (3)	0.029 (3)	0.040 (4)	−0.005 (3)	−0.002 (3)	−0.014 (3)
C4	0.039 (4)	0.037 (4)	0.050 (4)	−0.003 (3)	−0.005 (3)	−0.016 (3)
C5	0.042 (4)	0.067 (5)	0.049 (4)	−0.013 (4)	−0.011 (3)	−0.020 (4)
C6	0.051 (4)	0.060 (5)	0.060 (5)	−0.021 (4)	−0.006 (4)	−0.033 (4)
C7	0.050 (4)	0.042 (4)	0.054 (4)	−0.013 (3)	0.000 (3)	−0.024 (3)
C8	0.029 (3)	0.030 (3)	0.039 (3)	−0.007 (3)	0.001 (3)	−0.013 (3)
C9	0.029 (2)	0.015 (2)	0.047 (3)	−0.0009 (17)	−0.0031 (19)	−0.0070 (18)
C10	0.029 (2)	0.015 (2)	0.047 (3)	−0.0009 (17)	−0.0031 (19)	−0.0070 (18)
C11	0.035 (3)	0.033 (3)	0.043 (4)	−0.007 (3)	−0.001 (3)	−0.015 (3)
C12	0.056 (5)	0.040 (4)	0.070 (5)	−0.010 (3)	−0.011 (4)	−0.027 (4)
C13	0.067 (6)	0.070 (6)	0.070 (6)	−0.027 (5)	−0.012 (4)	−0.033 (5)
C14	0.038 (4)	0.068 (5)	0.058 (5)	−0.016 (4)	−0.010 (3)	−0.010 (4)
C15	0.040 (4)	0.044 (4)	0.046 (4)	0.003 (3)	−0.007 (3)	−0.012 (3)
C16	0.027 (3)	0.029 (3)	0.041 (4)	−0.007 (3)	−0.002 (3)	−0.009 (3)
C17	0.093 (6)	0.155 (8)	0.063 (5)	−0.052 (5)	−0.019 (4)	0.004 (5)
C18	0.093 (6)	0.155 (8)	0.063 (5)	−0.052 (5)	−0.019 (4)	0.004 (5)
C19	0.085 (7)	0.129 (9)	0.078 (7)	−0.048 (7)	−0.035 (6)	0.023 (6)
C20	0.104 (8)	0.198 (12)	0.060 (6)	−0.073 (8)	−0.026 (6)	0.003 (7)
Cd1	0.0293 (3)	0.0239 (3)	0.0508 (3)	0.00079 (18)	−0.00493 (19)	−0.0173 (2)
N1	0.027 (3)	0.025 (3)	0.042 (3)	−0.001 (2)	−0.003 (2)	−0.015 (2)
N2	0.037 (3)	0.015 (2)	0.050 (3)	0.000 (2)	−0.005 (2)	−0.013 (2)
N3	0.028 (3)	0.018 (2)	0.037 (3)	0.000 (2)	−0.004 (2)	−0.010 (2)
N4	0.035 (3)	0.028 (3)	0.050 (3)	−0.001 (2)	−0.009 (2)	−0.016 (2)
O1	0.025 (2)	0.037 (3)	0.058 (3)	−0.0013 (18)	−0.0109 (19)	−0.019 (2)
O2	0.047 (3)	0.015 (2)	0.071 (3)	0.009 (2)	−0.020 (2)	−0.016 (2)
O3	0.034 (2)	0.018 (2)	0.059 (3)	0.0038 (17)	−0.012 (2)	−0.018 (2)
O4	0.034 (3)	0.041 (3)	0.070 (3)	0.006 (2)	−0.017 (2)	−0.020 (2)
O5	0.049 (3)	0.067 (3)	0.040 (3)	−0.026 (3)	−0.006 (2)	−0.011 (2)
O6	0.043 (3)	0.054 (3)	0.045 (3)	−0.020 (2)	−0.008 (2)	−0.010 (2)

Geometric parameters (Å, º)

C1—O2	1.235 (7)	C14—C15	1.374 (10)
C1—O1	1.265 (7)	C14—H14	0.9300
C1—C2	1.515 (8)	C15—C16	1.394 (9)
C2—N2	1.291 (7)	C15—H15	0.9300
C2—N1	1.350 (8)	C16—N3	1.376 (7)
C3—N1	1.386 (8)	C17—O5	1.388 (11)
C3—C4	1.389 (9)	C17—C18	1.391 (14)
C3—C8	1.400 (8)	C17—H17A	0.9700
C4—C5	1.376 (10)	C17—H17B	0.9700
C4—H4	0.9300	C18—H18A	0.9600
C5—C6	1.393 (11)	C18—H18B	0.9600
C5—H5	0.9300	C18—H18C	0.9600
C6—C7	1.371 (10)	C19—C20	1.359 (12)
C6—H6	0.9300	C19—O6	1.377 (10)
C7—C8	1.387 (9)	C19—H19A	0.9700
C7—H7	0.9300	C19—H19B	0.9700
C8—N2	1.376 (8)	C20—H20A	0.9600
C9—O4	1.226 (7)	C20—H20B	0.9600
C9—O3	1.276 (7)	C20—H20C	0.9600
C9—C10	1.477 (8)	Cd1—N1	2.254 (5)
C10—N3	1.309 (7)	Cd1—N3	2.265 (5)
C10—N4	1.376 (8)	Cd1—O1	2.317 (4)
C11—N4	1.374 (8)	Cd1—O3	2.327 (4)
C11—C12	1.383 (9)	Cd1—O5	2.354 (5)
C11—C16	1.390 (8)	Cd1—O6	2.372 (5)
C12—C13	1.372 (11)	N2—H2	0.8600
C12—H12	0.9300	N4—H4A	0.8600
C13—C14	1.399 (11)	O5—H5A	0.8483
C13—H13	0.9300	O6—H6A	0.8475
O2—C1—O1	126.1 (6)	C17—C18—H18A	109.5
O2—C1—C2	116.7 (5)	C17—C18—H18B	109.5
O1—C1—C2	117.1 (5)	H18A—C18—H18B	109.5
N2—C2—N1	113.6 (5)	C17—C18—H18C	109.5
N2—C2—C1	126.7 (6)	H18A—C18—H18C	109.5
N1—C2—C1	119.6 (5)	H18B—C18—H18C	109.5
N1—C3—C4	131.5 (6)	C20—C19—O6	119.0 (9)
N1—C3—C8	108.9 (5)	C20—C19—H19A	107.6
C4—C3—C8	119.7 (6)	O6—C19—H19A	107.6
C5—C4—C3	118.0 (6)	C20—C19—H19B	107.6
C5—C4—H4	121.0	O6—C19—H19B	107.6
C3—C4—H4	121.0	H19A—C19—H19B	107.0
C4—C5—C6	121.0 (7)	C19—C20—H20A	109.5
C4—C5—H5	119.5	C19—C20—H20B	109.5
C6—C5—H5	119.5	H20A—C20—H20B	109.5
C7—C6—C5	122.5 (7)	C19—C20—H20C	109.5
C7—C6—H6	118.7	H20A—C20—H20C	109.5
C5—C6—H6	118.7	H20B—C20—H20C	109.5
C6—C7—C8	116.0 (7)	N1—Cd1—N3	177.57 (17)
C6—C7—H7	122.0	N1—Cd1—O1	74.26 (16)
C8—C7—H7	122.0	N3—Cd1—O1	105.53 (16)
N2—C8—C7	131.9 (6)	N1—Cd1—O3	105.98 (16)
N2—C8—C3	105.3 (5)	N3—Cd1—O3	74.21 (15)
C7—C8—C3	122.8 (6)	O1—Cd1—O3	179.45 (15)
O4—C9—O3	125.7 (6)	N1—Cd1—O5	93.64 (18)
O4—C9—C10	120.3 (5)	N3—Cd1—O5	88.78 (18)
O3—C9—C10	114.1 (5)	O1—Cd1—O5	89.37 (17)
N3—C10—N4	110.8 (5)	O3—Cd1—O5	91.10 (17)
N3—C10—C9	126.1 (5)	N1—Cd1—O6	86.32 (18)
N4—C10—C9	123.0 (5)	N3—Cd1—O6	91.26 (17)
N4—C11—C12	131.5 (6)	O1—Cd1—O6	90.58 (17)
N4—C11—C16	106.1 (5)	O3—Cd1—O6	88.95 (17)
C12—C11—C16	122.4 (6)	O5—Cd1—O6	179.94 (19)
C13—C12—C11	116.5 (7)	C2—N1—C3	103.9 (5)
C13—C12—H12	121.8	C2—N1—Cd1	112.6 (4)
C11—C12—H12	121.8	C3—N1—Cd1	142.7 (4)
C12—C13—C14	122.1 (7)	C2—N2—C8	108.4 (5)
C12—C13—H13	118.9	C2—N2—H2	125.8
C14—C13—H13	118.9	C8—N2—H2	125.8
C15—C14—C13	121.0 (7)	C10—N3—C16	107.4 (5)
C15—C14—H14	119.5	C10—N3—Cd1	109.8 (4)
C13—C14—H14	119.5	C16—N3—Cd1	142.8 (4)
C14—C15—C16	117.6 (7)	C11—N4—C10	107.1 (5)
C14—C15—H15	121.2	C11—N4—H4A	126.5
C16—C15—H15	121.2	C10—N4—H4A	126.5
N3—C16—C11	108.6 (5)	C1—O1—Cd1	115.0 (4)
N3—C16—C15	130.9 (6)	C9—O3—Cd1	115.3 (4)
C11—C16—C15	120.4 (6)	C17—O5—Cd1	134.8 (6)
O5—C17—C18	115.3 (10)	C17—O5—H5A	132.4
O5—C17—H17A	108.4	Cd1—O5—H5A	87.1
C18—C17—H17A	108.4	C19—O6—Cd1	135.6 (5)
O5—C17—H17B	108.4	C19—O6—H6A	113.5
C18—C17—H17B	108.4	Cd1—O6—H6A	101.7
H17A—C17—H17B	107.5
O2—C1—C2—N2	−1.3 (10)	N1—C2—N2—C8	0.7 (7)
O1—C1—C2—N2	179.1 (6)	C1—C2—N2—C8	−178.6 (6)
O2—C1—C2—N1	179.4 (6)	C7—C8—N2—C2	−178.5 (7)
O1—C1—C2—N1	−0.2 (9)	C3—C8—N2—C2	−0.7 (7)
N1—C3—C4—C5	−179.6 (7)	N4—C10—N3—C16	0.1 (7)
C8—C3—C4—C5	0.0 (10)	C9—C10—N3—C16	−177.2 (6)
C3—C4—C5—C6	0.9 (11)	N4—C10—N3—Cd1	−177.2 (4)
C4—C5—C6—C7	−0.7 (12)	C9—C10—N3—Cd1	5.5 (8)
C5—C6—C7—C8	−0.4 (11)	C11—C16—N3—C10	−0.1 (7)
C6—C7—C8—N2	178.8 (7)	C15—C16—N3—C10	−177.8 (7)
C6—C7—C8—C3	1.3 (10)	C11—C16—N3—Cd1	175.7 (5)
N1—C3—C8—N2	0.5 (7)	C15—C16—N3—Cd1	−2.0 (12)
C4—C3—C8—N2	−179.2 (6)	O1—Cd1—N3—C10	175.1 (4)
N1—C3—C8—C7	178.5 (6)	O3—Cd1—N3—C10	−5.4 (4)
C4—C3—C8—C7	−1.1 (10)	O5—Cd1—N3—C10	86.1 (4)
O4—C9—C10—N3	179.1 (6)	O6—Cd1—N3—C10	−94.0 (4)
O3—C9—C10—N3	−0.5 (9)	O1—Cd1—N3—C16	−0.6 (7)
O4—C9—C10—N4	2.1 (10)	O3—Cd1—N3—C16	178.9 (7)
O3—C9—C10—N4	−177.4 (6)	O5—Cd1—N3—C16	−89.7 (7)
N4—C11—C12—C13	−178.6 (7)	O6—Cd1—N3—C16	90.3 (7)
C16—C11—C12—C13	1.4 (11)	C12—C11—N4—C10	180.0 (8)
C11—C12—C13—C14	0.1 (13)	C16—C11—N4—C10	0.0 (7)
C12—C13—C14—C15	−1.1 (13)	N3—C10—N4—C11	0.0 (7)
C13—C14—C15—C16	0.5 (12)	C9—C10—N4—C11	177.3 (6)
N4—C11—C16—N3	0.1 (7)	O2—C1—O1—Cd1	−170.9 (5)
C12—C11—C16—N3	−179.9 (6)	C2—C1—O1—Cd1	8.7 (7)
N4—C11—C16—C15	178.0 (6)	N1—Cd1—O1—C1	−9.8 (4)
C12—C11—C16—C15	−2.0 (11)	N3—Cd1—O1—C1	167.7 (4)
C14—C15—C16—N3	178.4 (7)	O5—Cd1—O1—C1	−103.8 (5)
C14—C15—C16—C11	0.9 (10)	O6—Cd1—O1—C1	76.2 (5)
N2—C2—N1—C3	−0.4 (7)	O4—C9—O3—Cd1	175.5 (5)
C1—C2—N1—C3	179.0 (5)	C10—C9—O3—Cd1	−4.9 (7)
N2—C2—N1—Cd1	172.2 (4)	N1—Cd1—O3—C9	−176.7 (4)
C1—C2—N1—Cd1	−8.5 (7)	N3—Cd1—O3—C9	5.8 (4)
C4—C3—N1—C2	179.5 (7)	O5—Cd1—O3—C9	−82.6 (4)
C8—C3—N1—C2	−0.1 (7)	O6—Cd1—O3—C9	97.4 (4)
C4—C3—N1—Cd1	10.9 (12)	C18—C17—O5—Cd1	−37.1 (18)
C8—C3—N1—Cd1	−168.7 (5)	N1—Cd1—O5—C17	80.2 (10)
O1—Cd1—N1—C2	9.1 (4)	N3—Cd1—O5—C17	−100.1 (10)
O3—Cd1—N1—C2	−170.4 (4)	O1—Cd1—O5—C17	154.4 (10)
O5—Cd1—N1—C2	97.4 (4)	O3—Cd1—O5—C17	−25.9 (10)
O6—Cd1—N1—C2	−82.5 (4)	C20—C19—O6—Cd1	32.6 (19)
O1—Cd1—N1—C3	177.2 (7)	N1—Cd1—O6—C19	94.7 (10)
O3—Cd1—N1—C3	−2.3 (7)	N3—Cd1—O6—C19	−85.0 (10)
O5—Cd1—N1—C3	−94.5 (7)	O1—Cd1—O6—C19	20.5 (10)
O6—Cd1—N1—C3	85.5 (7)	O3—Cd1—O6—C19	−159.2 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O4^i	0.86	1.94	2.743 (6)	155
N4—H4A···O2^ii	0.86	1.94	2.761 (6)	158
O5—H5A···O3^iii	0.85	1.91	2.678 (6)	150
O6—H6A···O1^iv	0.85	1.85	2.678 (6)	164

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

(II) trans-bis(1H-benzimidazole-κN³)bis(1H- benzimidazole-2-carboxylato-κ²N³,O)nickel(II)

Crystal data

[Ni(C8H5N2O2)2(C7H6N2)2]	F(000) = 636
Mr = 617.27	Dx = 1.444 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3310 reflections
a = 10.321 (2) Å	θ = 2.1–28.1°
b = 12.923 (3) Å	µ = 0.74 mm^−1
c = 11.495 (2) Å	T = 298 K
β = 112.21 (3)°	Block, pale-purple
V = 1419.5 (5) Å^3	0.42 × 0.35 × 0.26 mm
Z = 2

Data collection

Bruker SMART APEXII CCD area-detector diffractometer	2787 independent reflections
Radiation source: fine-focus sealed tube	2374 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ϕ and ω scans	θmax = 26.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −12→12
Tmin = 0.748, Tmax = 0.832	k = −15→15
7496 measured reflections	l = −14→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.096	H-atom parameters constrained
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0465P)^2 + 0.7528P] where P = (Fo^2 + 2Fc^2)/3
2787 reflections	(Δ/σ)max < 0.001
184 parameters	Δρmax = 0.79 e Å^−3
6 restraints	Δρmin = −0.48 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.7526 (2)	−0.04615 (16)	0.04493 (19)	0.0273 (4)
C2	0.7228 (2)	0.04756 (16)	−0.03733 (19)	0.0271 (4)
C3	0.6268 (2)	0.18568 (17)	−0.1464 (2)	0.0327 (5)
C4	0.5430 (3)	0.2680 (2)	−0.2108 (2)	0.0458 (6)
H4	0.4508	0.2746	−0.2172	0.055*
C5	0.6027 (3)	0.3386 (2)	−0.2643 (2)	0.0513 (7)
H5	0.5493	0.3941	−0.3086	0.062*
C6	0.7409 (3)	0.3298 (2)	−0.2542 (2)	0.0479 (6)
H6	0.7775	0.3797	−0.2915	0.057*
C7	0.8247 (3)	0.24921 (19)	−0.1907 (2)	0.0405 (5)
H7	0.9172	0.2439	−0.1836	0.049*
C8	0.7652 (2)	0.17588 (16)	−0.13728 (19)	0.0306 (4)
C9	1.1027 (3)	0.19649 (18)	0.1560 (2)	0.0436 (6)
H9	1.0744	0.2348	0.0820	0.052*
C10	1.1328 (3)	0.07230 (19)	0.2859 (2)	0.0435 (6)
C11	1.1320 (5)	−0.0205 (2)	0.3448 (3)	0.0761 (11)
H11	1.0867	−0.0785	0.2999	0.091*
C12	1.2015 (5)	−0.0230 (3)	0.4731 (3)	0.1030 (9)
H12	1.2062	−0.0851	0.5155	0.124*
C13	1.2650 (5)	0.0644 (3)	0.5413 (3)	0.1030 (9)
H13	1.3070	0.0600	0.6284	0.124*
C14	1.2677 (5)	0.1568 (3)	0.4843 (3)	0.1030 (9)
H14	1.3137	0.2145	0.5296	0.124*
C15	1.1979 (3)	0.1594 (2)	0.3554 (2)	0.0476 (6)
N1	0.82193 (17)	0.08804 (13)	−0.06899 (16)	0.0284 (4)
N2	0.60315 (17)	0.10275 (14)	−0.08198 (17)	0.0322 (4)
H2	0.5265	0.0888	−0.0720	0.039*
N3	1.07517 (18)	0.09767 (14)	0.15964 (17)	0.0344 (4)
N4	1.1758 (2)	0.23675 (16)	0.2697 (2)	0.0471 (5)
H4A	1.2035	0.2998	0.2854	0.057*
Ni1	1.0000	0.0000	0.0000	0.02517 (13)
O1	0.87434 (14)	−0.08174 (11)	0.07459 (14)	0.0315 (3)
O2	0.66174 (15)	−0.08014 (12)	0.08110 (16)	0.0405 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0256 (10)	0.0271 (10)	0.0298 (10)	−0.0018 (8)	0.0111 (8)	−0.0005 (8)
C2	0.0222 (9)	0.0286 (10)	0.0310 (10)	0.0017 (8)	0.0107 (8)	0.0011 (9)
C3	0.0293 (11)	0.0333 (11)	0.0334 (11)	0.0019 (9)	0.0094 (9)	0.0026 (9)
C4	0.0353 (12)	0.0476 (14)	0.0478 (14)	0.0117 (11)	0.0081 (10)	0.0084 (12)
C5	0.0567 (16)	0.0413 (14)	0.0477 (15)	0.0137 (12)	0.0105 (12)	0.0159 (12)
C6	0.0577 (16)	0.0403 (13)	0.0453 (14)	0.0003 (12)	0.0192 (12)	0.0153 (11)
C7	0.0403 (12)	0.0405 (13)	0.0445 (13)	0.0005 (10)	0.0203 (11)	0.0096 (11)
C8	0.0295 (10)	0.0310 (11)	0.0306 (10)	0.0020 (8)	0.0105 (9)	0.0023 (9)
C9	0.0521 (14)	0.0347 (12)	0.0431 (13)	−0.0022 (11)	0.0169 (11)	−0.0041 (11)
C10	0.0510 (14)	0.0396 (13)	0.0373 (13)	0.0006 (11)	0.0137 (11)	−0.0039 (10)
C11	0.125 (3)	0.0495 (17)	0.0438 (17)	−0.0114 (19)	0.0200 (18)	−0.0003 (13)
C12	0.166 (2)	0.0707 (13)	0.0426 (11)	0.0016 (15)	0.0051 (13)	−0.0036 (9)
C13	0.166 (2)	0.0707 (13)	0.0426 (11)	0.0016 (15)	0.0051 (13)	−0.0036 (9)
C14	0.166 (2)	0.0707 (13)	0.0426 (11)	0.0016 (15)	0.0051 (13)	−0.0036 (9)
C15	0.0519 (15)	0.0445 (14)	0.0427 (14)	0.0036 (12)	0.0137 (12)	−0.0105 (11)
N1	0.0246 (8)	0.0288 (9)	0.0336 (9)	0.0023 (7)	0.0130 (7)	0.0048 (7)
N2	0.0212 (8)	0.0361 (10)	0.0403 (10)	0.0023 (7)	0.0126 (7)	0.0053 (8)
N3	0.0344 (10)	0.0326 (10)	0.0365 (10)	−0.0014 (8)	0.0138 (8)	−0.0029 (8)
N4	0.0550 (13)	0.0348 (11)	0.0529 (13)	−0.0090 (10)	0.0219 (10)	−0.0128 (10)
Ni1	0.02038 (19)	0.0257 (2)	0.0310 (2)	0.00080 (14)	0.01162 (15)	0.00160 (15)
O1	0.0240 (7)	0.0309 (8)	0.0417 (8)	0.0025 (6)	0.0146 (6)	0.0074 (6)
O2	0.0311 (8)	0.0403 (9)	0.0572 (10)	0.0020 (7)	0.0246 (8)	0.0132 (8)

Geometric parameters (Å, º)

C1—O2	1.241 (2)	C10—C11	1.379 (4)
C1—O1	1.258 (2)	C10—N3	1.384 (3)
C1—C2	1.495 (3)	C10—C15	1.396 (3)
C2—N1	1.317 (3)	C11—C12	1.375 (5)
C2—N2	1.349 (3)	C11—H11	0.9300
C3—N2	1.376 (3)	C12—C13	1.391 (5)
C3—C4	1.394 (3)	C12—H12	0.9300
C3—C8	1.398 (3)	C13—C14	1.367 (5)
C4—C5	1.370 (4)	C13—H13	0.9300
C4—H4	0.9300	C14—C15	1.382 (4)
C5—C6	1.392 (4)	C14—H14	0.9300
C5—H5	0.9300	C15—N4	1.361 (3)
C6—C7	1.374 (3)	N1—Ni1	2.0492 (17)
C6—H6	0.9300	N2—H2	0.8600
C7—C8	1.391 (3)	N3—Ni1	2.1181 (18)
C7—H7	0.9300	N4—H4A	0.8600
C8—N1	1.378 (3)	Ni1—N1^i	2.0492 (17)
C9—N3	1.312 (3)	Ni1—O1^i	2.0915 (14)
C9—N4	1.342 (3)	Ni1—O1	2.0915 (14)
C9—H9	0.9300	Ni1—N3^i	2.1181 (18)
O2—C1—O1	125.71 (19)	C14—C13—H13	119.0
O2—C1—C2	119.85 (17)	C12—C13—H13	119.0
O1—C1—C2	114.40 (17)	C13—C14—C15	116.0 (3)
N1—C2—N2	112.34 (18)	C13—C14—H14	122.0
N1—C2—C1	120.07 (17)	C15—C14—H14	122.0
N2—C2—C1	127.51 (17)	N4—C15—C14	132.1 (3)
N2—C3—C4	132.8 (2)	N4—C15—C10	105.4 (2)
N2—C3—C8	105.86 (18)	C14—C15—C10	122.5 (3)
C4—C3—C8	121.4 (2)	C2—N1—C8	106.13 (16)
C5—C4—C3	116.9 (2)	C2—N1—Ni1	110.44 (13)
C5—C4—H4	121.5	C8—N1—Ni1	143.43 (14)
C3—C4—H4	121.5	C2—N2—C3	107.05 (17)
C4—C5—C6	121.9 (2)	C2—N2—H2	126.5
C4—C5—H5	119.0	C3—N2—H2	126.5
C6—C5—H5	119.0	C9—N3—C10	104.6 (2)
C7—C6—C5	121.7 (2)	C9—N3—Ni1	124.40 (17)
C7—C6—H6	119.1	C10—N3—Ni1	129.71 (15)
C5—C6—H6	119.1	C9—N4—C15	107.4 (2)
C6—C7—C8	117.2 (2)	C9—N4—H4A	126.3
C6—C7—H7	121.4	C15—N4—H4A	126.3
C8—C7—H7	121.4	N1—Ni1—N1^i	180
N1—C8—C7	130.5 (2)	N1—Ni1—O1^i	99.52 (6)
N1—C8—C3	108.61 (18)	N1^i—Ni1—O1^i	80.48 (6)
C7—C8—C3	120.9 (2)	N1—Ni1—O1	80.48 (6)
N3—C9—N4	113.2 (2)	N1^i—Ni1—O1	99.52 (6)
N3—C9—H9	123.4	O1^i—Ni1—O1	180
N4—C9—H9	123.4	N1—Ni1—N3	89.17 (7)
C11—C10—N3	129.9 (2)	N1^i—Ni1—N3	90.83 (7)
C11—C10—C15	120.7 (3)	O1^i—Ni1—N3	88.48 (7)
N3—C10—C15	109.4 (2)	O1—Ni1—N3	91.52 (7)
C12—C11—C10	116.8 (3)	N1—Ni1—N3^i	90.83 (7)
C12—C11—H11	121.6	N1^i—Ni1—N3^i	89.17 (7)
C10—C11—H11	121.6	O1^i—Ni1—N3^i	91.52 (7)
C11—C12—C13	121.9 (4)	O1—Ni1—N3^i	88.48 (7)
C11—C12—H12	119.0	N3—Ni1—N3^i	180
C13—C12—H12	119.0	C1—O1—Ni1	114.51 (13)
C14—C13—C12	122.0 (3)
O2—C1—C2—N1	175.41 (19)	C1—C2—N2—C3	176.2 (2)
O1—C1—C2—N1	−2.4 (3)	C4—C3—N2—C2	−179.5 (3)
O2—C1—C2—N2	−1.2 (3)	C8—C3—N2—C2	0.1 (2)
O1—C1—C2—N2	−178.92 (19)	N4—C9—N3—C10	1.1 (3)
N2—C3—C4—C5	179.4 (2)	N4—C9—N3—Ni1	−166.88 (16)
C8—C3—C4—C5	−0.1 (4)	C11—C10—N3—C9	178.1 (3)
C3—C4—C5—C6	−0.6 (4)	C15—C10—N3—C9	−1.4 (3)
C4—C5—C6—C7	0.4 (4)	C11—C10—N3—Ni1	−14.8 (4)
C5—C6—C7—C8	0.5 (4)	C15—C10—N3—Ni1	165.70 (16)
C6—C7—C8—N1	−179.9 (2)	N3—C9—N4—C15	−0.4 (3)
C6—C7—C8—C3	−1.2 (3)	C14—C15—N4—C9	179.1 (4)
N2—C3—C8—N1	0.4 (2)	C10—C15—N4—C9	−0.5 (3)
C4—C3—C8—N1	−180.0 (2)	C2—N1—Ni1—O1^i	177.35 (14)
N2—C3—C8—C7	−178.6 (2)	C8—N1—Ni1—O1^i	−3.0 (2)
C4—C3—C8—C7	1.1 (3)	C2—N1—Ni1—O1	−2.65 (14)
N3—C10—C11—C12	178.6 (3)	C8—N1—Ni1—O1	177.0 (2)
C15—C10—C11—C12	−2.0 (6)	C2—N1—Ni1—N3	−94.33 (15)
C10—C11—C12—C13	2.5 (7)	C8—N1—Ni1—N3	85.4 (2)
C11—C12—C13—C14	−3.1 (8)	C2—N1—Ni1—N3^i	85.67 (15)
C12—C13—C14—C15	2.9 (7)	C8—N1—Ni1—N3^i	−94.6 (2)
C13—C14—C15—N4	178.1 (4)	C9—N3—Ni1—N1	−63.25 (19)
C13—C14—C15—C10	−2.4 (6)	C10—N3—Ni1—N1	131.9 (2)
C11—C10—C15—N4	−178.3 (3)	C9—N3—Ni1—N1^i	116.75 (19)
N3—C10—C15—N4	1.2 (3)	C10—N3—Ni1—N1^i	−48.1 (2)
C11—C10—C15—C14	2.0 (5)	C9—N3—Ni1—O1^i	36.30 (19)
N3—C10—C15—C14	−178.4 (3)	C10—N3—Ni1—O1^i	−128.5 (2)
N2—C2—N1—C8	0.8 (2)	C9—N3—Ni1—O1	−143.70 (19)
C1—C2—N1—C8	−176.29 (18)	C10—N3—Ni1—O1	51.5 (2)
N2—C2—N1—Ni1	−179.43 (14)	O2—C1—O1—Ni1	−177.79 (18)
C1—C2—N1—Ni1	3.5 (2)	C2—C1—O1—Ni1	−0.2 (2)
C7—C8—N1—C2	178.2 (2)	N1—Ni1—O1—C1	1.54 (14)
C3—C8—N1—C2	−0.7 (2)	N1^i—Ni1—O1—C1	−178.46 (14)
C7—C8—N1—Ni1	−1.5 (4)	N3—Ni1—O1—C1	90.45 (15)
C3—C8—N1—Ni1	179.63 (18)	N3^i—Ni1—O1—C1	−89.55 (15)
N1—C2—N2—C3	−0.6 (2)

Symmetry code: (i) −x+2, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H4A···O1^ii	0.86	2.56	3.111 (2)	123
N4—H4A···O2^ii	0.86	2.25	3.030 (3)	150
N2—H2···O2^iii	0.86	1.91	2.753 (2)	167

Symmetry codes: (ii) −x+2, y+1/2, −z+1/2; (iii) −x+1, −y, −z.