mer-Di­aqua­bis(1H-imidazole-[kappa]N³)(orotato-[kappa]²N³,O⁴)­nickel(II)

The title mononuclear complex, [Ni(C₅H₂N₂O₄)(C₃H₄N₂)₂(H₂O)₂] or [Ni(HOr)(im)₂(H₂O)₂] (im is imidazole and H₃Or is orotic acid, or 2,6-dioxo-1,2,3,6-tetra­hydro­pyrimidine-4-carboxylic acid), has been synthesized and the crystal structure determination is reported. The Ni^II ion in the complex has a distorted octahedral coordination geometry comprised of one deprotonated pyrimidine N atom and the adjacent carboxyl­ate O atom of the orotate ligand, two tertiary imidazole N atoms and two aqua ligands. An extensive three-dimensional network of OW-H...O and N-H...O hydrogen bonds, and [pi]-[pi] and [pi]-ring interactions are responsible for crystal stabilization.

S1. Comment

Orotic acid (H₃Or, vitamin B₁₃) and its metal complexes continue to attract attention because of its multidentate functionality and its great significance in living organisms as a precursor of pyrimidine nucleosides (Genchev, 1970; Rawn, 1989; Lalioti et al., 1998). For these reasons, metal orotates have recently attracted growing attention in medicine. Furthermore, nickel, magnesium, palladium and platinum orotate complexes have been screened as therapeutic agents for cancer treatment (Sabat et al., 1980; Karipides & Thomas, 1986; Castan et al., 1990; Kumberger et al., 1993). Orotic acid and its anions, H₂Or⁻, HOr²⁻ and Or³⁻, besides being biologically important, are also potentially interesting multidentate ligands, especially above the deprotonation pH values, coordinating to metal ions through the N atoms, the two carbonyl O atoms and the carboxylate O atoms. H₃Or can act as a dibasic acid, depending on the pH range. In the pH range 3–9, orotic acid exists mainly as the readily coordinating monodeprotonated HOr²⁻ anion (the carboxylic group has a pK of 2.07; Bach et al., 1990; Lutz, 2001). In basic solutions (pH > 9), both carboxyl H and heterocylic N atoms are deprotonated, so the anion acts as a bidentate ligand. Existing studies of its coordination complexes demonstrate that it occurs as a dianion, often coordinating via the N atom and carboxylic acid group, so forming a five-membered chelate ring (Mutikainen, 1987; Mutikainen et al., 1996; Maistralis et al., 2000; Wysokinski et al., 2002; Icbudak et al., 2003; Ölmez et al., 2004). In polymeric orotic acid complexes, the orotate anion bridges the metal ions through the carboxylate and N and O atoms, forming one-dimensional polymeric chains (Castan et al., 1998; Ha et al., 1999; Sun et al., 2002). Imidazole is of considerable interest as a ligand because its presence in many biological systems (Valle & Wacker, 1970; Tamura et al., 1987), for example, in the histidyl residue of proteins, provides a potential binding site for metal ions. Imidazole is a monodentate ligand and forms complexes with metal ions through its tertiary N atom (Brooks & Davidson, 1960; Inoue et al., 1966; Davis & Smith, 1971; Wang et al., 2000; Hao et al., 2000). In this paper, we report the preparation and crystal structure of the title complex, (I), incorporating both oratate and imidazole ligands. This compound might be of interest in pharmacological studies. \sch

The crystal structure of (I) is presented in Fig. 1. The Ni^II ion has a distorted octahedral coordination geometry comprised of atom N1 and a carboxylate O atom from a bis-deprotonated bidentate orotate ligand, two aqua O atoms and two tertiary N atoms from imidazole molecules. Atoms N1 and O3 are bonded to Ni1 to form a five-membered chelate ring [N1—Ni1 2.0719 (15) and O3—Ni1 2.0635 (12) Å], water atom O1 [Ni—O1 2.0716 (13) Å] and imidazole atom N5 [Ni—N5 2.0721 (16) Å] form the equatorial plane, and the other water atom, O2 [Ni—O2 2.162 (14) Å], and imidazole atom N3 [Ni—N3 2.0745 (16) Å] are in the apical positions of the Ni^II coordination octahedron. The equatorial plane is approximately planar, with an r.m.s. deviation of 0.0432 Å, and the largest deviation from the mean plane is 0.0805 (6) Å for atom Ni1. For the two symmetry-unrelated Ni—OW (aqua ligands) bond lengths, we might expect to observe two similar values; in fact, they are quite different (see above). This is apparently due to the strong intramolecular hydrogen-bonding interaction between atom H1A of the aqua ligand and the exocyclic atom O6 [Fig. 2; O1···O6 2.712 (19) Å]. This interaction is also the reason that the molecule forms the mer-isomer instead of the fac-isomer. All the N—Ni—N, N—Ni—O and O—Ni—O bond angles deviate significantly from 90 and 180°, which is presumably a result of the steric constraints arising from the shape of the ligands. The angle subtended at the Ni atom by the orotate ligand is 80.12 (5)°, which is in agreement with values previously reported for other orotate-containing Ni^II complexes (Sabat et al., 1980; Wysokinski et al., 2002). This `bite' angle is far from the ideal value of 90°, because of the constrained geometry of the orotate ligands.

The orotate ligand in (I) is essentially planar (r.m.s. deviation 0.0444 Å), with a slight deviation from planarity arising from the non-zero torsion angle between the carboxylate group and the ring [N1—C2—C1—O3 2.5 (2)°]. This torsion angle indicates that distortion of the orotate ligand caused by coordination to the Ni^II ion is even less than in uncoordinated orotic acid [5.9 (4)° (Falvello et al., 2003) and 5.0 (2)° (Bulut et al., 2003)]. Of all the N—C bonds in the uracyclic ring of the orotate ligand, N1—C5 and N1—C2 are the shortest, at 1.346 (2) and 1.355 (2) Å, respectively. This indicates a considerabe π-electron delocalization within the C3—C2—N1—C5 skeleton. The C═O bond lengths for the exocylclic atoms O5 and O6 are 1.257 (2) and 1.252 (2) Å, respectively. These values are slightly longer than those in typical orotate complexes, and this can be attributed to the intermolecular hydrogen bonding (Table 2).

The orotate molecule seems to have a degree of elasticity involving coordination to metal centres. In complexes of HOr²⁻ with Ni (this work; Sabat et al., 1980; Wysonkinski et al., 2002), Cu (Mutikainen & Lumme, 1980) and Zn (Mutikainen, 1987), the C5—N1—C2 angle is smaller [118.25 (15), 118.3 (3), 118.9 (11), 117.9 (2) and 118.1 (4)°, respectively] than that found in orotic acid [122.8 (3) (Takusagawa & Shimada, 1973), 123.07 (14) (Bulut et al., 2003) and 122.8 (3)° (Falvello et al., 2003)]. This shrinking of the C5—N1—N2 angle is due to the metal coordination at N1, which causes widening of the adjacent N1—C2—C3 and N1—C–N2 angles to 124.79 (16) and 118.01 (15)°, respectively [120.82 (16) and 115.15 (14)°, respectively, in Bulut et al. (2003)].

The carboxylate C—O distances in the orotate anion also display some variability, depending on their environment. The C—O distances are practically equal in the uncoordinated HOr²⁻ anion and its Ni^II and Li complexes (Lutz, 2001). In (I), the C—O bond lengths are in the range 1.248 (2)–1.253 (2) Å, which is comparable with those in similar nickel^II complexes (Sabat et al., 1980; Wysokinski et al., 2002). However, in the Co^II, Cu^II (Icbudak et al., 2003) and Mg^II (Mutikainen et al., 1996) complexes of HOr²⁻, the carboxylate group [C—O 1.278 (2)–1.223 (3), 1.270 (4)–1.240 (4) and 1.262 (2)–1.243 (2) Å, respectively] is asymmetric.

The two imidazole rings in (I) are individually planar, with r.m.s. deviations of 0.0028 and 0.0007 Å, and the maximum deviations from these planes are 0.0039 (15) Å for atom N4 and 0.0010 (13) Å for atom C7. These planes are approximately perpendicular, with a dihedral angle of 88.17 (8)°. The dihedral angles between the orotate ligand and the imidazole groups are 81.43 (6) and 10.98 (11)°. The internal geometries are as expected, with the N3—C11 [1.306 (3) Å], N5—C8 [1.321 (2) Å], C9—C10 [1.346 (3) Å] and C6—C7[1.348 (3) Å] bond lengths corresponding exactly to typical double-bond lengths. These values are comparable with those in mixed-ligand imidazole Ni^II complexes (Wang et al., 1999; Hao et al., 2000; Gao et al., 2004).

The crystal packing of (I) is formed by intermolecular hydrogen-bonding, and π–π and π-ring interactions. It is seen from Fig. 2 that the two orotate molecules are joined by two N2—H4···O5 hydrogen bonds (Table 2), which leads to the formation of a centrosymmetric dimer of (I) in the crystal unit cell. Similar behaviour was also reported in the work of Wysokinski et al. (2002). Two aqua ligands and the imidazole atoms N4 and N6 also form intermolecular hydrogen-bonding interactions, through carboxylate atom O4 and exocylic carbonyl atoms O5 and O6 (see Table 2 for details). In the extended structure of (I), shown in Fig. 2, there are also weak π–π and π-ring interactions. An intermolecular π–π contact occurs between the two symmetry-related imidazole rings (N3-coordinated, hereinafter ring A) of neighbouring molecules. Ring A is oriented in such a way that the perpendicular distance from A to A^vii is 3.351 Å, the closest interatomic distance being C10···C11^vii [3.438 (4) Å; symmetry code: (vii) 1 − x, −y, 1 − z]. The distance between the ring centroids is 3.6610 (14) Å. The other imidazole ring (N5-coordinated, ring B) also forms an intermolecular π–π contact, with the uracilate ring (C) of the orotate ligand. Rings B and C are oriented in such a way that the perpendicular distance from B to C is 3.578 Å, the closest interatomic distance is C6···C4ⁱⁱⁱ [3.443 (3) Å; symmetry code: (iii) x − 1, y, z], and the dihedral angle between the planes of the rings is 10.8°. The distance between the ring centroids is 3.9717 (12) Å. Rings A and B are also involved in intermolecular N—H···π and C—H···π interactions with the imidazole N and C atoms. For the N—H···π contact, for two neighbouring A rings, the distance between atom H11 and the centre of ring A (CgA) is 3.35 (3) Å, the distance between atom H11 and the plane of ring A is 3.311 Å and the N4—H11···CgA angle is 84.0 (18)°. In addition, there are also two C—H···π interactions between rings A and B. For the C10—H10···π contact, the distance between atom H10 and the centre of ring B (CgB) is 2.9048 Å, the distance between atom H10 and the plane of ring B is 2.807 Å and the C10—H10···CgB angle is 137.18°. For the C7—H7···π contact, the distance between atom H7 and the centre of ring A is 3.0057 Å, the distance between atom H7 and the plane of ring A is 2.988 Å and the C7—H7···CgA angle is 173.17°.

S2. Experimental

To prepare [Ni(HOr)(H₂O)₄]·H₂O, a mixture of a solution of NiCl₂·6H₂O (1.19 g, 5 mmol) in distilled water (25 ml) and a solution of NaHCO₃ (0.42 g, 5 mmol) in distilled water (25 ml) was added dropwise with stirring at 353 K to a suspension of orotic acid (0.87 g, 5 mmol) in distilled water (25 ml). The mixture was refluxed with stirring for 24 h at 353 K in a temperature-controlled bath and, after evolution of CO₂, the clear solution was cooled to room temperature. The green crystals which formed were filtered and washed with 10 ml of cold distilled water and acetone and dried in vacuo. To prepare [Ni(HOr)(H₂O)₂(im)₂], (I), a solution of imidazole (0.55 g, 4 mmol) in ethanol (10 ml) was added dropwise with stirring to a solution of [Ni(HOr)(H₂O)₄]·H₂O (0.62 g, 2 mmol) in distilled water (50 ml). The mixture was heated to 333 K in a temperature-controlled bath and refluxed with stirring for 12 h at 333 K. The reaction mixture was then cooled to room temperature. The blue crystals of (I) which formed were filtered and washed with 10 ml of cold distilled water and ethanol and dried in vacuo.

S3. Refinement

H bound to C atoms were placed in calculated positions, with C—H = 0.93 Å, and were allowed to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C). The remaining H atoms were located in the difference map and refined, with O—H distances restrained to 0.85 (2) Å and N—H distances restrained to 0.87 (2) Å.

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. The three-dimensional structure of (I). Dashed lines illustrate the hydrogen bonds, and π–π and π-ring interactions. [Symmetry codes: (iii) x − 1, y, z; (vii) 1 − x, −y, 1 − z.]

mer-Diaquabis(1H-imidazole-κN³)(orotato-κ²N,O)nickel(II)

Crystal data

[Ni(C5H2N2O4)(C3H4N2)2(H2O)2]	F(000) = 792
Mr = 384.97	Dx = 1.642 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 20639 reflections
a = 8.6201 (6) Å	θ = 1.5–28.5°
b = 13.5104 (7) Å	µ = 1.29 mm^−1
c = 13.5612 (10) Å	T = 293 K
β = 99.627 (6)°	Prism, blue
V = 1557.11 (18) Å^3	0.3 × 0.27 × 0.24 mm
Z = 4

Data collection

Stoe IPDS-2 diffractometer	3068 independent reflections
Radiation source: fine-focus sealed tube	2658 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
Detector resolution: 6.67 pixels mm^-1	θmax = 26.0°, θmin = 2.1°
ω scans	h = −10→10
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)	k = −16→16
Tmin = 0.701, Tmax = 0.755	l = −16→16
21831 measured reflections

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)] = 0.027	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.072	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0482P)^2] where P = (Fo^2 + 2Fc^2)/3
3068 reflections	(Δ/σ)max < 0.001
245 parameters	Δρmax = 0.20 e Å^−3
7 restraints	Δρmin = −0.52 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Ni1	0.44933 (3)	0.117996 (15)	0.211852 (16)	0.02582 (9)
O1	0.36419 (16)	−0.01940 (10)	0.16094 (10)	0.0319 (3)
O2	0.33851 (17)	0.17949 (10)	0.07031 (10)	0.0342 (3)
O3	0.54553 (15)	0.25640 (9)	0.24457 (10)	0.0323 (3)
O4	0.71821 (17)	0.36158 (9)	0.19782 (10)	0.0360 (3)
O5	1.02248 (16)	0.13439 (10)	0.00127 (11)	0.0360 (3)
O6	0.63738 (16)	−0.05377 (9)	0.09246 (10)	0.0352 (3)
N1	0.64454 (17)	0.10825 (10)	0.14159 (11)	0.0260 (3)
N2	0.83128 (19)	0.04361 (11)	0.05326 (12)	0.0288 (3)
N3	0.57200 (19)	0.06166 (12)	0.34464 (11)	0.0332 (3)
N4	0.6839 (2)	0.05159 (15)	0.50100 (13)	0.0455 (4)
N5	0.24833 (19)	0.14822 (12)	0.27156 (11)	0.0319 (3)
N6	0.0868 (2)	0.22473 (14)	0.35392 (14)	0.0433 (4)
C1	0.6548 (2)	0.27821 (12)	0.19861 (13)	0.0280 (4)
C2	0.7197 (2)	0.19620 (12)	0.13982 (12)	0.0256 (3)
C3	0.8451 (2)	0.21256 (13)	0.09316 (14)	0.0304 (4)
H3	0.8894	0.2752	0.0923	0.036*
C4	0.9061 (2)	0.13141 (13)	0.04597 (13)	0.0281 (4)
C5	0.6995 (2)	0.03016 (12)	0.09634 (13)	0.0262 (4)
C6	0.1232 (2)	0.08763 (15)	0.27890 (15)	0.0351 (4)
H8	0.1099	0.0239	0.2529	0.042*
C7	0.0225 (2)	0.13410 (16)	0.32948 (16)	0.0410 (5)
H7	−0.0715	0.1094	0.3445	0.049*
C8	0.2217 (3)	0.23082 (15)	0.31805 (16)	0.0404 (5)
H5	0.2877	0.2857	0.3249	0.048*
C9	0.6455 (3)	−0.02825 (16)	0.36090 (16)	0.0432 (5)
H9	0.6476	−0.0771	0.3128	0.052*
C10	0.7142 (3)	−0.03486 (18)	0.45737 (17)	0.0496 (6)
H10	0.7711	−0.0882	0.4880	0.059*
C11	0.5976 (3)	0.10680 (16)	0.43099 (16)	0.0424 (5)
H12	0.5602	0.1697	0.4422	0.051*
H1A	0.441 (3)	−0.041 (2)	0.1334 (19)	0.061 (8)*
H1B	0.342 (3)	−0.0585 (19)	0.2058 (17)	0.067 (9)*
H2A	0.358 (3)	0.1394 (17)	0.0270 (17)	0.053 (8)*
H2B	0.244 (2)	0.177 (2)	0.0670 (19)	0.051 (7)*
H4	0.863 (3)	−0.0075 (14)	0.0273 (15)	0.037 (6)*
H6	0.056 (3)	0.2692 (17)	0.3895 (19)	0.060 (8)*
H11	0.710 (3)	0.065 (2)	0.5625 (14)	0.068 (9)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.02910 (14)	0.02366 (13)	0.02690 (14)	−0.00066 (9)	0.01112 (9)	−0.00097 (8)
O1	0.0375 (7)	0.0269 (6)	0.0332 (7)	−0.0026 (6)	0.0118 (6)	0.0004 (5)
O2	0.0349 (8)	0.0342 (7)	0.0340 (7)	0.0030 (6)	0.0072 (6)	−0.0002 (6)
O3	0.0372 (7)	0.0267 (6)	0.0374 (7)	−0.0027 (5)	0.0187 (6)	−0.0054 (5)
O4	0.0454 (8)	0.0227 (6)	0.0445 (8)	−0.0056 (6)	0.0209 (6)	−0.0064 (5)
O5	0.0334 (7)	0.0322 (7)	0.0482 (8)	−0.0004 (6)	0.0236 (6)	−0.0011 (6)
O6	0.0428 (8)	0.0239 (6)	0.0442 (7)	−0.0049 (6)	0.0230 (6)	−0.0064 (5)
N1	0.0291 (8)	0.0225 (7)	0.0286 (7)	−0.0002 (6)	0.0109 (6)	−0.0011 (5)
N2	0.0307 (8)	0.0237 (7)	0.0355 (8)	0.0009 (6)	0.0153 (6)	−0.0046 (6)
N3	0.0375 (8)	0.0344 (8)	0.0286 (8)	−0.0015 (7)	0.0083 (7)	0.0003 (6)
N4	0.0541 (11)	0.0541 (11)	0.0270 (9)	−0.0011 (9)	0.0028 (8)	−0.0017 (8)
N5	0.0352 (8)	0.0306 (8)	0.0325 (8)	0.0009 (7)	0.0130 (7)	−0.0020 (6)
N6	0.0421 (10)	0.0462 (10)	0.0453 (10)	0.0087 (8)	0.0185 (8)	−0.0083 (8)
C1	0.0329 (9)	0.0236 (8)	0.0280 (8)	0.0014 (7)	0.0068 (7)	−0.0017 (6)
C2	0.0282 (8)	0.0228 (8)	0.0270 (8)	0.0008 (7)	0.0078 (7)	0.0001 (7)
C3	0.0326 (10)	0.0231 (8)	0.0377 (9)	−0.0008 (7)	0.0128 (8)	−0.0002 (7)
C4	0.0281 (9)	0.0282 (9)	0.0301 (9)	0.0018 (7)	0.0115 (7)	0.0014 (7)
C5	0.0307 (9)	0.0238 (8)	0.0265 (8)	0.0015 (7)	0.0118 (7)	−0.0006 (6)
C6	0.0339 (10)	0.0340 (9)	0.0385 (10)	−0.0009 (8)	0.0095 (8)	−0.0006 (8)
C7	0.0338 (10)	0.0492 (12)	0.0420 (11)	−0.0001 (9)	0.0124 (9)	0.0029 (9)
C8	0.0440 (12)	0.0357 (10)	0.0453 (11)	−0.0015 (9)	0.0187 (9)	−0.0079 (9)
C9	0.0509 (13)	0.0385 (11)	0.0393 (11)	0.0067 (10)	0.0045 (9)	−0.0016 (9)
C10	0.0558 (14)	0.0485 (12)	0.0420 (12)	0.0099 (11)	0.0010 (10)	0.0062 (10)
C11	0.0534 (13)	0.0398 (11)	0.0336 (10)	0.0017 (9)	0.0060 (9)	−0.0039 (8)

Geometric parameters (Å, º)

Ni1—O3	2.0635 (12)	N4—C11	1.332 (3)
Ni1—O1	2.0716 (13)	N4—C10	1.354 (3)
Ni1—N1	2.0719 (15)	N4—H11	0.847 (17)
Ni1—N5	2.0721 (16)	N5—C8	1.321 (2)
Ni1—N3	2.0745 (16)	N5—C6	1.371 (3)
Ni1—O2	2.1620 (14)	N6—C8	1.335 (3)
O1—H1A	0.866 (17)	N6—C7	1.362 (3)
O1—H1B	0.852 (17)	N6—H6	0.842 (17)
O2—H2A	0.836 (17)	C1—C2	1.525 (2)
O2—H2B	0.811 (17)	C2—C3	1.359 (3)
O3—C1	1.248 (2)	C3—C4	1.415 (2)
O4—C1	1.253 (2)	C3—H3	0.9300
O5—C4	1.257 (2)	C6—C7	1.348 (3)
O6—C5	1.252 (2)	C6—H8	0.9300
N1—C5	1.346 (2)	C7—H7	0.9300
N1—C2	1.355 (2)	C8—H5	0.9300
N2—C4	1.362 (2)	C9—C10	1.346 (3)
N2—C5	1.373 (2)	C9—H9	0.9300
N2—H4	0.842 (16)	C10—H10	0.9300
N3—C11	1.306 (3)	C11—H12	0.9300
N3—C9	1.371 (3)
O3—Ni1—O1	172.26 (5)	C8—N6—C7	108.09 (18)
O3—Ni1—N1	80.12 (5)	C8—N6—H6	123.1 (19)
O1—Ni1—N1	93.41 (6)	C7—N6—H6	128.6 (19)
O3—Ni1—N5	93.99 (6)	O3—C1—O4	125.67 (16)
O1—Ni1—N5	91.95 (6)	O3—C1—C2	117.57 (15)
N1—Ni1—N5	171.37 (6)	O4—C1—C2	116.74 (16)
O3—Ni1—N3	91.01 (6)	N1—C2—C3	124.79 (16)
O1—Ni1—N3	93.51 (6)	N1—C2—C1	114.18 (15)
N1—Ni1—N3	92.33 (6)	C3—C2—C1	121.01 (16)
N5—Ni1—N3	94.09 (6)	C2—C3—C4	118.01 (16)
O3—Ni1—O2	86.83 (5)	C2—C3—H3	121.0
O1—Ni1—O2	88.23 (5)	C4—C3—H3	121.0
N1—Ni1—O2	83.59 (6)	O5—C4—N2	119.27 (16)
N5—Ni1—O2	89.83 (6)	O5—C4—C3	125.50 (16)
N3—Ni1—O2	175.66 (6)	N2—C4—C3	115.20 (16)
Ni1—O1—H1A	101.3 (18)	O6—C5—N1	123.26 (16)
Ni1—O1—H1B	115.3 (19)	O6—C5—N2	118.73 (15)
H1A—O1—H1B	112 (3)	N1—C5—N2	118.01 (15)
Ni1—O2—H2A	105.3 (18)	C7—C6—N5	109.89 (18)
Ni1—O2—H2B	109.0 (18)	C7—C6—H8	125.1
H2A—O2—H2B	105 (3)	N5—C6—H8	125.1
C1—O3—Ni1	114.59 (11)	C6—C7—N6	105.76 (19)
C5—N1—C2	118.25 (15)	C6—C7—H7	127.1
C5—N1—Ni1	129.39 (12)	N6—C7—H7	127.1
C2—N1—Ni1	112.31 (11)	N5—C8—N6	110.70 (19)
C4—N2—C5	125.56 (15)	N5—C8—H5	124.7
C4—N2—H4	119.5 (16)	N6—C8—H5	124.7
C5—N2—H4	114.8 (15)	C10—C9—N3	109.37 (19)
C11—N3—C9	105.39 (17)	C10—C9—H9	125.3
C11—N3—Ni1	126.31 (14)	N3—C9—H9	125.3
C9—N3—Ni1	128.29 (13)	C9—C10—N4	106.37 (19)
C11—N4—C10	107.27 (18)	C9—C10—H10	126.8
C11—N4—H11	127 (2)	N4—C10—H10	126.8
C10—N4—H11	125 (2)	N3—C11—N4	111.59 (19)
C8—N5—C6	105.56 (17)	N3—C11—H12	124.2
C8—N5—Ni1	125.22 (14)	N4—C11—H12	124.2
C6—N5—Ni1	129.05 (13)
N1—Ni1—O3—C1	10.21 (12)	C5—N1—C2—C1	−176.36 (14)
N5—Ni1—O3—C1	−163.44 (13)	Ni1—N1—C2—C1	6.08 (18)
N3—Ni1—O3—C1	102.39 (13)	O3—C1—C2—N1	2.5 (2)
O2—Ni1—O3—C1	−73.83 (13)	O4—C1—C2—N1	−178.70 (15)
O3—Ni1—N1—C5	174.32 (16)	O3—C1—C2—C3	−175.77 (17)
O1—Ni1—N1—C5	−9.97 (15)	O4—C1—C2—C3	3.0 (2)
N3—Ni1—N1—C5	83.69 (16)	N1—C2—C3—C4	−2.5 (3)
O2—Ni1—N1—C5	−97.80 (15)	C1—C2—C3—C4	175.59 (16)
O3—Ni1—N1—C2	−8.46 (12)	C5—N2—C4—O5	−177.32 (17)
O1—Ni1—N1—C2	167.25 (12)	C5—N2—C4—C3	4.1 (3)
N3—Ni1—N1—C2	−99.09 (12)	C2—C3—C4—O5	−178.88 (17)
O2—Ni1—N1—C2	79.42 (12)	C2—C3—C4—N2	−0.4 (2)
O3—Ni1—N3—C11	38.79 (18)	C2—N1—C5—O6	−178.92 (17)
O1—Ni1—N3—C11	−147.50 (18)	Ni1—N1—C5—O6	−1.8 (3)
N1—Ni1—N3—C11	118.94 (18)	C2—N1—C5—N2	1.7 (2)
N5—Ni1—N3—C11	−55.29 (19)	Ni1—N1—C5—N2	178.78 (12)
O3—Ni1—N3—C9	−139.77 (18)	C4—N2—C5—O6	175.73 (17)
O1—Ni1—N3—C9	33.95 (18)	C4—N2—C5—N1	−4.9 (3)
N1—Ni1—N3—C9	−59.61 (18)	C8—N5—C6—C7	0.1 (2)
N5—Ni1—N3—C9	126.16 (18)	Ni1—N5—C6—C7	175.47 (13)
O3—Ni1—N5—C8	−4.21 (17)	N5—C6—C7—N6	−0.2 (2)
O1—Ni1—N5—C8	−179.25 (17)	C8—N6—C7—C6	0.2 (2)
N3—Ni1—N5—C8	87.09 (17)	C6—N5—C8—N6	0.0 (2)
O2—Ni1—N5—C8	−91.02 (17)	Ni1—N5—C8—N6	−175.57 (14)
O3—Ni1—N5—C6	−178.78 (16)	C7—N6—C8—N5	−0.2 (3)
O1—Ni1—N5—C6	6.19 (16)	C11—N3—C9—C10	−0.1 (3)
N3—Ni1—N5—C6	−87.48 (17)	Ni1—N3—C9—C10	178.70 (16)
O2—Ni1—N5—C6	94.41 (16)	N3—C9—C10—N4	−0.4 (3)
Ni1—O3—C1—O4	171.44 (15)	C11—N4—C10—C9	0.7 (3)
Ni1—O3—C1—C2	−9.9 (2)	C9—N3—C11—N4	0.5 (3)
C5—N1—C2—C3	1.8 (3)	Ni1—N3—C11—N4	−178.29 (14)
Ni1—N1—C2—C3	−175.72 (14)	C10—N4—C11—N3	−0.8 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O6	0.86 (3)	1.88 (3)	2.712 (2)	163 (2)
O1—H1B···O4^i	0.85 (2)	1.84 (2)	2.686 (2)	176 (2)
O2—H2A···O6^ii	0.84 (2)	2.00 (2)	2.820 (2)	168 (2)
O2—H2B···O5^iii	0.81 (2)	2.05 (2)	2.796 (2)	153 (3)
N2—H4···O5^iv	0.84 (2)	2.05 (2)	2.869 (2)	165 (2)
N6—H6···O5^v	0.84 (2)	2.06 (2)	2.880 (2)	167 (2)
N4—H11···O4^vi	0.85 (2)	2.08 (2)	2.885 (2)	160 (3)

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