Tetra­aqua­bis­(pyridine-3-carbo­nitrile-κN ¹)nickel(II) benzene-1,4-di­carboxyl­ate tetra­hydrate

The structure of a nickel(II) terephthalate complex, viz. tetra­aqua­bis­(pyridine-3-carbo­nitrile)­nickel(II) benzene-1,4-di­carboxyl­ate tetra­hydrate is described.

Abstract

A nickel(II) terephthalate complex, viz. [Ni(C₆H₄N₂)₂(H₂O)₄](O₂CC₆H₄CO₂)·4H₂O, has been synthesized and studied by single-crystal X-ray diffraction. It crystallizes in the triclinic space group P . The crystal structure shows an approximately octa­hedral coordination environment of the complex with the [Ni(H₂O)₄(3-NCpy)₂]²⁺ (3-NCpy is pyridine-3-carbo­nitrile) cation associated with four free water mol­ecules and hydrogen bonded to a terephthalate dianion [graph set R ² ₂(8)]. The supra­molecular structure of the compound is stabilized by a three-dimensional array of O—H⋯O and O—H⋯N hydrogen bonds, along with π–π stacked pyridine-3-carbo­nitrile rings and C—H⋯O inter­actions.

Chemical context  

Multi-carboxyl­ate ligands with suitable spacers, especially benzene-multi­carboxyl­ate ligands, are frequent choices for coordination chemistry as they feature a broad range of coordination modes and can result in the formation of systems with variable complexity ranging from mol­ecular complexes to metal–organic frameworks of different dimensionality (Janiak & Vieth, 2010 ▸; Kim et al., 2001 ▸). Benzene-1,4-di­carboxyl­ate (terephthalate) ligands have received increased attention in the field of coordination chemistry, especially as building blocks for coordination polymers, mainly with porous networks with varied metal ions (Kim et al., 2003 ▸). As a result of the presence of conjugation, the terephthalate anion can provide an electronic pathway for delocalization of electrons belonging to the d-orbitals of the metal ion, thus changing its magnetic properties. The most important factor that affects magnetic exchange pathways between two metal centres is the proper choice of bridging ligands since they influence the magnetic strength and behaviour of the mol­ecule (Massoud et al., 2006 ▸; Mukherjee et al., 2003 ▸; Rogan et al., 2000 ▸). Coordinated ligand systems containing electron-donor as well as acceptor sites also give rise to metallo­supra­molecular assemblies. Hence, pyridine-3-carbo­nitrile (3-NCpy) with the electron-withdrawing nitrile group as the acceptor along with the pyridyl nitro­gen atom as the donor stands as a suitable ligand in this regard. Despite the availability of two potentially coordinating sites, not many compounds having pyridine-3-carbo­nitrile as a bidentate bridging ligand are known (Heine et al., 2018 ▸). The nitrile group may also be expected to take part in hydrogen bonding and π–π inter­actions. In this work, we describe our results on the synthesis and crystal structure of a pyridine-3-carbo­nitrile-based Ni^II–terephthalate complex, viz. [Ni(H₂O)₄(3-NCpy)₂][O₂CC₆H₄CO₂]·4H₂O.

Structural commentary  

The title compound, [Ni(H₂O)₄(3-NCpy)₂][O₂CC₆H₄CO₂]·4H₂O is a discrete coordination complex and it crystallizes in the triclinic system with space group P . An ORTEP view is shown in Fig. 1 ▸. The compound consists of a complex dication, which is in association with four free water mol­ecules and an uncoordinated terephthalate dianion, where the asymmetric unit contains half of these qu­anti­ties. The Ni²⁺ centre is situated on an inversion centre and coordinates to two axial pyridine-3-carbo­nitrile ligands and four equatorial water mol­ecules forming the cationic complex [Ni(H₂O)₄(3-CNpy)₂]²⁺. The bond angles in the cationic part suggest that the complex contains an Ni²⁺ ion in an approximately octa­hedral coordination environment [cis angles in the range of 88.66 (4)–91.33 (4)°]. The free terephthalate anion is also located on an inversion centre and has an angle of 14.54 (7)° between the planes of the aromatic ring and of the carboxyl­ate group. Furthermore, it does not coordinate to the Ni²⁺ ion and remains fully deprotonated for charge balance. It also acts as a secondary acceptor to the cationic complex unit. The Ni—O bond lengths are 2.0381 (11) and 2.0519 (9) Å and are in agreement with similar complexes reported (Xiao et al., 2003 ▸; Ma & Xu, 2010 ▸; Ju et al., 2016 ▸). The Ni—N bond length of 2.1481 (11) Å is slightly longer than those in the similar complexes reported by Zukerman-Schpector et al. (2000 ▸) and Heine et al. (2018 ▸).

Figure 1.

ORTEP diagram of [Ni(H₂O)₄(3-NCpy)₂][O₂CC₆H₄CO₂]·4H₂O showing the atom-labelling scheme (ellipsoids drawn at the 50% probability level; unlabelled atoms generated by the symmetry operations 2 − x, 2 − y, −z for the cation and 1 − x, 1 − y, 1 − z for the anion).

Supra­molecular features  

The supra­molecular structure of the title compound is consolidated by several O—H⋯O and O—H⋯N hydrogen bonds that involve all the possible hydrogen-bond acceptors and donors, which result in the formation of a three-dimensional hydrogen-bonded array in the crystal (Table 1 ▸, Figs. 2 ▸–4 ▸ ▸). The two-dimensional hydrogen-bonded layers featured in Fig. 2 ▸ are connected together via hydrogen bonds described by the (8) graph set depicted in Fig. 3 ▸. The cationic complex and the terephthalate dianion are hydrogen bonded via the O1—H1B⋯O4 and O2—H2A⋯O3 inter­actions within the (8) graph set and form infinite chains (Fig. 3 ▸). Neighbouring chains are inter­connected by O1—H1A⋯O5 and O5—H5B⋯N2 hydrogen bonds described by an (20) graph set, π–π inter­actions arising from stacking of the 3-NCpy rings [centroid–centroid distance of 3.727 (8) Å, with a slippage of 1.067 Å, Fig. 4 ▸]. The cavity formed is filled by the four solvent water mol­ecules (O5, O6) inter­connecting two neighbouring terephthalate dianions by a cooperative O—H⋯O ring network with an (12) motif, forming infinite chains in a zigzag fashion along the a-axis direction (Fig. 3 ▸). Finally, the three-dimensional network is further accomplished among others by the (7) O2—H2B⋯O6 hydrogen bonds and C2—H2⋯O3 and C5—H5⋯O3 inter­actions (Table 1 ▸, Fig. 2 ▸). A comprehensive list of first and second level graph sets can be found in Table 2 ▸.

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2A⋯O3i	0.84 (1)	1.80 (1)	2.6301 (14)	171 (2)
C5—H5⋯O3i	0.93	2.46	3.1832 (17)	135
O1—H1A⋯O5ii	0.83 (1)	1.94 (1)	2.7591 (17)	171 (2)
O2—H2B⋯O6iii	0.83 (1)	1.86 (1)	2.6710 (17)	168 (2)
O1—H1B⋯O4iv	0.84 (1)	1.87 (1)	2.7050 (14)	176 (2)
O6—H6A⋯O4v	0.82 (1)	2.01 (1)	2.8240 (17)	174 (2)
O6—H6B⋯O5vi	0.84 (1)	2.07 (1)	2.855 (2)	156 (2)
O5—H5A⋯O4v	0.83 (1)	1.95 (1)	2.7645 (17)	167 (2)
O5—H5B⋯N2vii	0.83 (1)	2.12 (1)	2.950 (2)	176 (2)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

Figure 2.

Packing structure of the complex showing the hydrogen bonds and C—H⋯O and π–π inter­actions.

Figure 3.

Hydrogen-bonding pattern associated with the (8), (8) and (12) graph sets.

Figure 4.

Hydrogen-bonded pattern associated with the (20) graph set and π–π inter­actions between two 3-NCpy rings.

Table 2. Graph-set descriptions.

Graph set	Level	Period	No. of Mol­ecules
(2) a	1		2
(7) <a>a	1		3
(2) b	1		2
(13) >b<b	1	2	3
(2) c	1		2
(13) >c<c	1	2	3
(2) d	1		2
(7) <d>d	1		3
(2) e	1		2
(10) >e<e	1		3
(2) f	1		2
(13) >f<f	1		3
(2) g	1		2
(10) >g<g	1		3
(2) h	1		2
(10) >a>f	2	2	3
(8) >b<c	2	2	2
(20) >a>f>a>f	2	2	4

a = H1A⋯O5, b = H1B⋯O4, c = H2A⋯O3, d = H2B⋯O6, e = H5A⋯O4, f = H5B⋯N2, g = H6A⋯O4 and h = H6B⋯O5.

Database survey  

A survey of the Cambridge Structural Database (CSD version 2020.2; Groom et al., 2016 ▸) for Ni^II complexes involving an uncoordinated terephthalate dianion led us to a few results, some of which are as follows. In the complex [Ni(2,2′-bipy)(H₂O)₄](C₈H₄O₄) (2,2′-bipy = 2,2′-bipyrid­yl) (CSD refcode: WUWZET) reported by Xiao et al. (2003 ▸), the terephthalate anion acts as a synthon to generate a supra­molecular network. The hydrogen bonds between the terephthalate anions and the [Ni(2,2′-bipy)(H₂O)₄]²⁺ cations produce a two-dimensional hydrogen-bonded architecture with double sheets. A similar compound, tetra­aqua­bis­(di­methyl­formamide)­nickel(II) tetra­chloro­terephthalate, (QAMDUF; Ma & Xu, 2010 ▸) has a nearly ideal octa­hedral structure with the metal ion lying on an inversion center along with an uncomplexed and fully deprotonated terephthalate dianion. Another Ni^II–terephthalate complex (AJUPEC; Ju et al., 2016 ▸) with 4,7-di(4-pyrid­yl)-2,1,3-benzo­thia­diazole as auxiliary ligand crystallizes in the monoclinic P2₁/c space group. The terephthalate dianion remains uncoordinated and the Ni^II ion sits in the centre of an octa­hedron constituted by two pyridyl N atoms in the apical positions and four water oxygen atoms constructing the equatorial plane. The independent cationic units are held together by π–π stacking inter­actions and O—H⋯O hydrogen bonding, generating a compact packing structure. A pyrazine-based Ni^II–terephthalate complex (AGIWOC; Groeneman & Atwood, 2000 ▸) is a one-dimensional zigzag coordination polymer, where each nickel centre has two cis μ-pyrazine ligands along with four coordinated water mol­ecules, giving rise to a distorted octa­hedral coordination environment. A survey of Ni^II complexes involving pyridine-3-carbo­nitrile as ligand led us to some other related structures. Heine et al. (2018 ▸) investigated the ability of pyridine-3-carbo­nitrile to act as a mono- or bidentate ligand in complexes of the type [M ^IIBr₂(3-CNpy)_x]_n with M ^II = Mn, Fe, Co, Ni and x = 1, 2 and 4, (CSD refcodes XOSNUR, XOSPAZ, XOSPAZ02) and found that the pyridine-3-carbo­nitrile ligand acted as bridging ligand in complexes with a metal:ligand ratio of 1:1 and as a terminal ligand with ratios of 1:2 and 1:4. In an adduct of Ni^II acetyl­acetonate chelating with pyridine-3-carbo­nitrile (MASTUV; Zukerman-Schpector et al., 2000 ▸), the Ni^II atom is situated on a centre of symmetry and is octa­hedrally bonded to two equatorial AcAc groups and two pyridine-3-carbo­nitrile groups, which are axially coordinated in a trans configuration.

Synthesis and crystallization  

All reagents were purchased from E. Merck and used without further purification. A mixture of nickel(II) sulfate hepta­hydrate, NiSO₄·7H₂O (1.120 g, 4 mmol) and disodium terephthalate, Na₂C₈H₄O₄ (0.840 g, 4 mmol) was dissolved in 20 mL of water in a 100 mL round-bottomed flask. To this, 0.832 g (8 mmol) of pyridine-3-carbo­nitrile was added and the resulting reaction mixture was stirred mechanically for 2 h. A light-green precipitate was formed. It was filtered, washed with water under suction and dried in a vacuum desiccator over fused CaCl₂. Green prism-shaped single crystals of the title compound suitable for X-ray diffraction studies were obtained from the undisturbed aqueous reaction solutions after 24 h, yield 73% (1.675 g). The compound is air stable and insoluble in common organic solvents. The crystals remained indefinitely stable against dehydration under ambient conditions. IR spectroscopic data (KBr disc, cm⁻¹): ν _asym(OCO⁻) 1568, ν _sym(OCO⁻) 1365, ν(C=N) 1602, ν(CN_py) 2243, δ _asym(OCO⁻) 810, δ _sym(OCO⁻) 748. Decomposition point 270°C.

Refinement  

Crystal data, data collection and structure refinement details are summarized in Table 3 ▸. The non-hydrogen atoms were refined with anisotropic displacement parameters. C-bound hydrogen atoms were placed in idealized positions with C—H = 0.95–0.99 Å, and refined as riding with U _iso(H) = 1.2U _eq(C) or 1.5U _eq(C-meth­yl).

Table 3. Experimental details.

Crystal data
Chemical formula	[Ni(C6H4N2)2(H2O)4](C8H4O4)·4H2O
M r	575.17
Crystal system, space group	Triclinic, P
Temperature (K)	293
a, b, c (Å)	8.5709 (17), 8.6760 (17), 9.2644 (19)
α, β, γ (°)	77.26 (3), 81.99 (3), 77.34 (3)
V (Å3)	652.6 (3)
Z	1
Radiation type	Mo Kα
μ (mm−1)	0.81
Crystal size (mm)	0.34 × 0.32 × 0.19
Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 2016 ▸)
T min, T max	0.752, 0.826
No. of measured, independent and observed [I > 2σ(I)] reflections	12067, 3762, 3635
R int	0.026
(sin θ/λ)max (Å−1)	0.704
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.026, 0.074, 1.05
No. of reflections	3762
No. of parameters	194
No. of restraints	14
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.33, −0.40

Computer programs: APEX and SAINT (Bruker, 2004 ▸), SHELXT2014/5 (Sheldrick, 2015a ▸), SHELXL2017/1 (Sheldrick, 2015b ▸), ORTEP-3 for Windows (Farrugia, 2012 ▸), Mercury (Macrae et al., 2020 ▸) and publCIF (Westrip, 2010 ▸).

Supplementary Material

CCDC reference: 1538307

Additional supporting information: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Crystal data

[Ni(C6H4N2)2(H2O)4](C8H4O4)·4H2O	Z = 1
Mr = 575.17	F(000) = 300
Triclinic, P1	Dx = 1.463 Mg m−3
a = 8.5709 (17) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.6760 (17) Å	Cell parameters from 4157 reflections
c = 9.2644 (19) Å	θ = 3.4–28.3°
α = 77.26 (3)°	µ = 0.81 mm−1
β = 81.99 (3)°	T = 293 K
γ = 77.34 (3)°	Prism, green
V = 652.6 (3) Å3	0.34 × 0.32 × 0.19 mm

Data collection

Bruker APEXII CCD diffractometer	3762 independent reflections
Radiation source: fine-focus sealed tube	3635 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
Detector resolution: 8.333 pixels mm-1	θmax = 30.0°, θmin = 2.3°
phi and ω scans	h = −11→12
Absorption correction: multi-scan (SADABS; Sheldrick, 2016)	k = −12→12
Tmin = 0.752, Tmax = 0.826	l = −12→12
12067 measured reflections

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.026	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.074	w = 1/[σ2(Fo2) + (0.0422P)2 + 0.1177P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max < 0.001
3762 reflections	Δρmax = 0.33 e Å−3
194 parameters	Δρmin = −0.40 e Å−3
14 restraints	Extinction correction: SHELXL2017/1 (Sheldrick 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.213 (7)

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.

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

	x	y	z	Uiso*/Ueq
Ni1	1.000000	1.000000	0.000000	0.02537 (8)
O1	0.98267 (11)	0.96951 (11)	−0.21023 (9)	0.03464 (18)
H1A	0.990 (2)	1.0424 (15)	−0.2842 (15)	0.052*
H1B	1.025 (2)	0.8825 (13)	−0.2376 (19)	0.052*
O2	0.85605 (10)	1.22212 (10)	−0.04411 (9)	0.03425 (17)
H2A	0.8004 (19)	1.262 (2)	0.0256 (14)	0.051*
H2B	0.894 (2)	1.2951 (17)	−0.1021 (16)	0.051*
O3	0.66032 (11)	0.32360 (13)	0.17543 (10)	0.0441 (2)
O4	0.86703 (10)	0.30492 (11)	0.30301 (10)	0.0407 (2)
O5	0.03827 (14)	0.21002 (14)	0.54999 (11)	0.0508 (2)
H5A	−0.026 (2)	0.237 (3)	0.4851 (19)	0.076*
H5B	0.1233 (16)	0.160 (3)	0.514 (2)	0.076*
O6	0.03774 (18)	0.55747 (17)	0.26293 (14)	0.0633 (3)
H6A	−0.011 (3)	0.484 (2)	0.268 (3)	0.095*
H6B	−0.006 (3)	0.610 (3)	0.328 (2)	0.095*
N1	0.78988 (11)	0.89668 (11)	0.07505 (11)	0.03167 (19)
N2	0.33024 (18)	1.0277 (3)	0.4103 (2)	0.0778 (5)
C1	0.75634 (16)	0.78588 (15)	0.00979 (14)	0.0390 (2)
H1	0.832785	0.744160	−0.060450	0.047*
C2	0.61331 (19)	0.73082 (19)	0.04213 (17)	0.0493 (3)
H2	0.594395	0.654339	−0.006152	0.059*
C3	0.49961 (17)	0.79021 (19)	0.14618 (17)	0.0483 (3)
H3	0.401786	0.756363	0.168663	0.058*
C4	0.53433 (14)	0.90164 (16)	0.21666 (14)	0.0394 (3)
C5	0.68038 (13)	0.95226 (15)	0.17811 (13)	0.0350 (2)
H5	0.702508	1.027604	0.225918	0.042*
C6	0.42063 (16)	0.9712 (2)	0.32545 (18)	0.0533 (4)
C7	0.44154 (14)	0.43845 (16)	0.39715 (14)	0.0383 (3)
H7	0.401890	0.397181	0.328307	0.046*
C8	0.60607 (13)	0.42491 (13)	0.39660 (12)	0.0322 (2)
C9	0.66387 (14)	0.48662 (16)	0.49989 (14)	0.0388 (3)
H9	0.773958	0.477732	0.500156	0.047*
C10	0.71845 (14)	0.34553 (13)	0.28278 (13)	0.0334 (2)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Ni1	0.02417 (11)	0.02844 (11)	0.02502 (11)	−0.00512 (7)	0.00326 (6)	−0.01197 (7)
O1	0.0414 (4)	0.0360 (4)	0.0276 (4)	−0.0048 (3)	0.0005 (3)	−0.0138 (3)
O2	0.0352 (4)	0.0318 (4)	0.0329 (4)	−0.0020 (3)	0.0064 (3)	−0.0108 (3)
O3	0.0389 (5)	0.0569 (6)	0.0407 (5)	−0.0020 (4)	0.0028 (3)	−0.0297 (4)
O4	0.0332 (4)	0.0468 (5)	0.0435 (5)	0.0005 (3)	0.0029 (3)	−0.0242 (4)
O5	0.0513 (6)	0.0591 (6)	0.0366 (5)	−0.0033 (5)	−0.0014 (4)	−0.0071 (4)
O6	0.0782 (8)	0.0595 (7)	0.0548 (7)	−0.0331 (6)	0.0061 (6)	−0.0049 (5)
N1	0.0283 (4)	0.0326 (4)	0.0354 (5)	−0.0073 (3)	0.0000 (3)	−0.0097 (4)
N2	0.0392 (7)	0.1149 (15)	0.0757 (10)	−0.0070 (8)	0.0116 (7)	−0.0295 (10)
C1	0.0431 (6)	0.0373 (6)	0.0400 (6)	−0.0124 (5)	−0.0033 (5)	−0.0110 (5)
C2	0.0564 (8)	0.0489 (7)	0.0515 (8)	−0.0271 (6)	−0.0113 (6)	−0.0084 (6)
C3	0.0382 (6)	0.0576 (8)	0.0513 (7)	−0.0239 (6)	−0.0087 (5)	0.0017 (6)
C4	0.0263 (5)	0.0468 (6)	0.0406 (6)	−0.0077 (4)	−0.0013 (4)	0.0004 (5)
C5	0.0281 (5)	0.0376 (5)	0.0397 (6)	−0.0077 (4)	0.0019 (4)	−0.0105 (4)
C6	0.0286 (6)	0.0724 (10)	0.0542 (8)	−0.0096 (6)	0.0030 (5)	−0.0075 (7)
C7	0.0347 (6)	0.0467 (6)	0.0391 (6)	−0.0053 (5)	0.0019 (4)	−0.0262 (5)
C8	0.0324 (5)	0.0323 (5)	0.0323 (5)	−0.0020 (4)	0.0044 (4)	−0.0162 (4)
C9	0.0297 (5)	0.0487 (7)	0.0414 (6)	−0.0035 (5)	0.0031 (4)	−0.0245 (5)
C10	0.0348 (5)	0.0312 (5)	0.0341 (5)	−0.0033 (4)	0.0071 (4)	−0.0160 (4)

Geometric parameters (Å, º)

Ni1—O2i	2.0381 (11)	N1—C1	1.3409 (15)
Ni1—O2	2.0381 (11)	N2—C6	1.136 (2)
Ni1—O1i	2.0519 (9)	C1—C2	1.3828 (19)
Ni1—O1	2.0519 (9)	C1—H1	0.9300
Ni1—N1i	2.1481 (11)	C2—C3	1.372 (2)
Ni1—N1	2.1481 (11)	C2—H2	0.9300
O1—H1A	0.829 (9)	C3—C4	1.381 (2)
O1—H1B	0.839 (9)	C3—H3	0.9300
O2—H2A	0.838 (9)	C4—C5	1.3909 (16)
O2—H2B	0.828 (9)	C4—C6	1.438 (2)
O3—C10	1.2396 (15)	C5—H5	0.9300
O4—C10	1.2735 (15)	C7—C9ii	1.3873 (16)
O5—H5A	0.830 (9)	C7—C8	1.3885 (17)
O5—H5B	0.830 (9)	C7—H7	0.9300
O6—H6A	0.822 (9)	C8—C9	1.3864 (17)
O6—H6B	0.837 (9)	C8—C10	1.5035 (15)
N1—C5	1.3342 (15)	C9—H9	0.9300
O2i—Ni1—O2	180.00 (5)	N1—C1—H1	118.5
O2i—Ni1—O1i	89.76 (5)	C2—C1—H1	118.5
O2—Ni1—O1i	90.24 (5)	C3—C2—C1	119.30 (13)
O2i—Ni1—O1	90.24 (5)	C3—C2—H2	120.4
O2—Ni1—O1	89.76 (5)	C1—C2—H2	120.4
O1i—Ni1—O1	180.0	C2—C3—C4	118.21 (12)
O2i—Ni1—N1i	89.33 (4)	C2—C3—H3	120.9
O2—Ni1—N1i	90.67 (4)	C4—C3—H3	120.9
O1i—Ni1—N1i	88.66 (4)	C3—C4—C5	119.42 (12)
O1—Ni1—N1i	91.33 (4)	C3—C4—C6	121.56 (12)
O2i—Ni1—N1	90.67 (4)	C5—C4—C6	118.98 (13)
O2—Ni1—N1	89.33 (4)	N1—C5—C4	122.40 (12)
O1i—Ni1—N1	91.33 (4)	N1—C5—H5	118.8
O1—Ni1—N1	88.67 (4)	C4—C5—H5	118.8
N1i—Ni1—N1	180.0	N2—C6—C4	179.2 (2)
Ni1—O1—H1A	122.0 (12)	C9ii—C7—C8	120.18 (11)
Ni1—O1—H1B	121.0 (12)	C9ii—C7—H7	119.9
H1A—O1—H1B	106.7 (15)	C8—C7—H7	119.9
Ni1—O2—H2A	120.0 (12)	C9—C8—C7	119.43 (10)
Ni1—O2—H2B	118.1 (12)	C9—C8—C10	121.09 (10)
H2A—O2—H2B	107.6 (15)	C7—C8—C10	119.47 (10)
H5A—O5—H5B	107.4 (17)	C8—C9—C7ii	120.39 (11)
H6A—O6—H6B	107.9 (18)	C8—C9—H9	119.8
C5—N1—C1	117.63 (10)	C7ii—C9—H9	119.8
C5—N1—Ni1	120.87 (8)	O3—C10—O4	124.25 (10)
C1—N1—Ni1	121.17 (8)	O3—C10—C8	117.83 (11)
N1—C1—C2	123.01 (13)	O4—C10—C8	117.92 (10)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O3iii	0.84 (1)	1.80 (1)	2.6301 (14)	171 (2)
C5—H5···O3iii	0.93	2.46	3.1832 (17)	135
O1—H1A···O5iv	0.83 (1)	1.94 (1)	2.7591 (17)	171 (2)
O2—H2B···O6v	0.83 (1)	1.86 (1)	2.6710 (17)	168 (2)
O1—H1B···O4vi	0.84 (1)	1.87 (1)	2.7050 (14)	176 (2)
O6—H6A···O4vii	0.82 (1)	2.01 (1)	2.8240 (17)	174 (2)
O6—H6B···O5viii	0.84 (1)	2.07 (1)	2.855 (2)	156 (2)
O5—H5A···O4vii	0.83 (1)	1.95 (1)	2.7645 (17)	167 (2)
O5—H5B···N2ix	0.83 (1)	2.12 (1)	2.950 (2)	176 (2)

Symmetry codes: (iii) x, y+1, z; (iv) x+1, y+1, z−1; (v) −x+1, −y+2, −z; (vi) −x+2, −y+1, −z; (vii) x−1, y, z; (viii) −x, −y+1, −z+1; (ix) x, y−1, z.

Funding Statement

This work was funded by UGC, India grant .