
==== Front
IUCrdata
IUCrdata
IUCrData
IUCrData
2414-3146
International Union of Crystallography

zl4073
10.1107/S2414314624008101
IUCRBK
S2414314624008101
Data Reports
Bis[μ-3-(pyridin-2-yl)pyrazolato]bis­[acetato­(3,5-dimethyl-1H-pyrazole)­nickel(II)]
[Ni2(C8H6N3)2(C2H3O2)2(C5H8N2)2]
Pilavadi Thangamuniyandi a
https://orcid.org/0000-0003-4167-6931
Krishnan Soundararajan b
Loganathan Nagarajan a*‡
a https://ror.org/02w7vnb60 School of Chemistry Bharathidasan University, Tiruchirappalli 620 024 Tamilnadu India
b Department of Chemistry, Periyar Maniammai Institute of Science and Technology, Vallam-613403, Thanjavur, Tamil Nadu, India
Zeller M. Editor
Purdue University, USA
Correspondence e-mail: l.nagarajan@bdu.ac.in
‡ UGC-Faculty Recharge Programme, New Delhi, India.

8 2024
30 8 2024
30 8 2024
9 Pt 8 x240800 x24081001 6 2024
16 8 2024
© Pilavadi et al. 2024
2024
https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
A full version of this article is available from Crystallography Journals Online.
The title compound is a dimeric nickel(II) coordination compound containing two different substituted pyrazoles ligands, namely 3,5-di­methyl­pyrazole and 3-(pyridin-2-yl) pyrazole along with acetate.

The title compound, [Ni2(C8H6N3)2(C2H3O2)2(C5H8N2)2] or [Ni(μ-OOCCH3)(2-PyPz)(Me2PzH)]2 (1) [2-PyPz = 3-(pyridin-2-yl) pyrazole; Me2PzH = 3,5-dimethyl pyrazole] was synthesized from Ni(OOCCH3)2·4H2O, 2-PyPzH, Me2PzH and tri­ethyl­amine as a base. Compound 1 {[Ni2(C30H34N10Ni2O4)]} at 100 K has monoclinic (P21/n) symmetry and the mol­ecules have crystallographic inversion symmetry. Mol­ecules of 1 comprise an almost planar dinuclear NiII core with an N4O2 coordination environment. The equatorial plane consists of N3,O coordination derived from one of the bidentate acetate O atoms and three of the N atoms of the chelating 2-PyPz ligand while the axial positions are occupied by neutral Me2PzH and the second O atom of the acetate unit. The Ni atoms are bridged by the nitro­gen atom of a deprotonated 2-PyPz ligand. Compound 1 exhibits various inter- and intra­molecular C—H⋯O and N—H⋯O hydrogen bonds.

coordination compound
nickel
3,5-di­methyl­pyrazole
3-(pyridin-2-yl) pyrazole
heteroleptic complex
crystal structure
Science and Engineering Research Board, India, Early Career Research Award ECR/2016/001966 Nagarajan Loganathan Science and Engineering Research Board, India, EMEQ Scheme EEQ2018/001373 Rashtriya Uchchatar Shiksha Abhiyan, Physical Sciences 2.0 (RUSA 2.0)
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pmcStructure description

Noble metals such as palladium, platinum or iridium are widely used in catalysis due to their desirable properties such as the ability to tolerate variable coordination states and oxidation states that predispose them towards catalysing two-electron redox processes, while at the same time also being sufficiently stable and thermally stable to be of practical use. A major drawback is, however, their high price and limited availability. As an alternative to scarce 4 and 5d metals, their more earth-abundant 3d congeners have been investigated, and in particular several nickel-catalysed organic transform­ation strategies were developed and established (Wilke, 1988 ▸; Keim, 1990 ▸; Montgomery, 2004 ▸; Tasker et al., 2014 ▸; Diccianni et al., 2020 ▸). These include C—C and C—X (X = heteroatom) cross-coupling (Rosen et al., 2011 ▸), cyclo­addition (Lautens et al., 1996 ▸; Komagawa et al., 2013 ▸), asymmetric hydrogenation (Vermaak et al., 2024 ▸), photo-redox catalysis (Milligan et al., 2019 ▸; Cuesta-Galisteo et al., 2024 ▸), reductive coupling (Day et al., 2023 ▸) and reductive cyclization reactions (Montgomery, 2004 ▸) to name just a few. The inability of nickel to catalyse two-electron transformations can be overcome by the placement of more than one metal atom at the catalytic centre, and dinuclear nickel complexes show an enhanced catalytic activity and a higher robustness that can be traced back to the synergistic inter­action between the two metals in the active site (Uyeda & Farley 2021 ▸; Xu et al., 2020 ▸). Nickel is also a micronutrient and essential for the biosynthesis of hydrogenase, carbon monoxide de­hydrogenase (CODH) and urease. These enzymes require more than one metal active site to catalyse the enzymatic process. This also substanti­ates the crucial role of the presence of more than one metal centre for 3d-metal-based catalysts.

We are inter­ested in synthesizing dimeric NiII complexes utilizing chelating ligands such as 2-PyPzH [3-(2-pyridyl)pyrazole, C8H7N3]. The use of pyrazole ligands in coordination and organometallic chemistry is well established (Trofimenko, 1972 ▸; Mukherjee, 2000 ▸; Halcrow, 2009 ▸; Viciano-Chumillas et al., 2010 ▸). 2-PyPzH usually forms planar dimeric [M(μ-2-PyPz)2]2 units that are thermally stable. Copper-based dimeric complexes with a {[Cu(μ-2-PyPz)2]2}n core have been described (Jeffery et al., 1997 ▸; Hu et al., 2006 ▸; Das et al., 2019 ▸). However, to the best of our knowledge, the analogous nickel complex with an [Ni(μ-2-PyPz)2]n core is unknown. Thus, a reaction was carried out between nickel(II)acetate tetra­hydrate, 2-PyPzH as the primary ligand and highly lipophilic 3,5-di­methyl­pyrazole (Me2PzH) as an ancillary ligand and a small excess of tri­ethyl­amine base in methanol solvent. This was done in a 1:1:5:3.5 ratio, which resulted in the formation of a green solid, which was then recrystallized from methanol solvent to obtain blue crystals of [Ni2(μ-OOCCH3)2(2-PyPz)2(Me2PzH)2] (1). Inter­estingly, the initial reaction between nickel(II)acetate tetra­hydrate, 2-PyPzH and tri­ethyl­amine base in a 1:1:1.5 stoichiometry failed and led to an intra­ctable mixture. However, the addition of a large excess of Me2PzH allowed us to isolate the soluble mol­ecular assembly of 1 (Fig. 1 ▸).

Compound 1 crystallizes in the monoclinic P21/n space group, in which the asymmetric unit contains half of the mol­ecule. Compound 1 is a dinuclear heteroleptic nickel(II) complex consisting of two each of anionic 2-PyPz, anionic CH3COO− and neutral Me2PzH ligands and the complex mol­ecules have crystallographic inversion symmetry. Overall, the two nickel atoms (Ni1 and Ni1i) are bridged through the 2-PyPz ligand and each Ni atom has an N4O2 octa­hedral coordination environment around it. The three N-donors (N1, N2 and N3i) are derived from the 2-PyPz unit, which forms the basal plane of the dimer while the fourth N-coordination (N4) is obtained from the axial neutral Me2PzH ligand. The acetate ligand (O1 and O2) exhibits a syn–syn symmetric binding mode (κ2 mode) in which O2 is in the equatorial position while the sixth axial position is occupied by O1.

The following is a summary of the bonding parameters found in compound 1 in which each Ni atom exhibits three different Ni—N distances and two different Ni—O distances. The Ni—N distance involving the anionic pyrazole unit is shorter [Ni1—N2 = 2.0245 (12); Ni1—N3i = 2.0409 (13) Å] compared to the pyridinic N of 2-PyPz [Ni1—N1 = 2.0964 (13) Å] and the neutral Me2PzH ligand [Ni1—N4 = 2.0884 (12) Å]. Additionally, the axial Ni—O distances are longer [Ni1—O1 = 2.1848 (11) Å] than the equatorial distance [Ni1— O2 = 2.1232 (11) Å]. Furthermore, the C—O distances are not equal [C14—O1 = 1.2576 (19); C14—O2 = 1.2641 (19) Å]. It is noteworthy that the dimeric [Ni(μ-2-PyPz)(COOCH3)]2 unit is almost planar, with the two basal trans angles being less than 180° [O1—Ni1—N4 = 170.18 (5); N1—Ni1—N3i = 177.68 (5)°]. The angle between the two apical positions is the most acute [O2—Ni1—N2 = 157.80 (5)°]. Finally, of the twelve right angles around Ni1, seven are closer to 90° [average O—Ni—N = 89.16 (4) and average N—Ni—N = 91.03 (6)°], and the remaining three are obtuse [N2—Ni1—N3i = 100.88 (5); O1—Ni1—N2 = 99.02 (5); O2—Ni1—N4 = 109.07 (5)°].

Compound 1 exhibits several intra- and inter­molecular hydrogen bonds (Table 1 ▸, Fig. 2 ▸), with atom N6 of Me2PzH forming intra­molecular hydrogen bonds with O1 of the acetate (N6—H6⋯O1i and the reciprocal N6i—H6i⋯O1 3.0800 (17) Å; symmetry code: (i) −x, −y, −z + 1), with N2 [N6—H6⋯N2 2.9931 (18) Å] and N3 [N6—H6⋯N3 3.3065 (18) Å] of 2-PyPz, while the two O atoms of acetate (O1 and O2) inter­act with the pyridine C—H of 2-PyPz and pyrazolyl C—H of Me2PzH. Thus, the hydrogen bonding between C2—H2⋯O2ii [3.2692 (19) Å; symmetry code: (ii) −x + , y + , −z + ] and C4—H4⋯O1iii [3.4696 (19) Å; symmetry code: (iii) −x, −y + 1, −z + 1] are inter­molecular in nature while the C9—H9C⋯O1i [3.426 (2) Å], C1—H1⋯O2 [3.1281 (19) Å] and C13—H13B⋯O2 [3.530 (2) Å] are of intra­molecular type.

Synthesis and crystallization

0.5 mmol of Ni(OOCCH3)2·4H2O (0.1244 g) was dissolved in 30 ml of methanol. Then, 0.5 mmol of 2-PyPzH (0.0726 g) and 0.79 mmol of tri­ethyl­amine (0.11 ml) were added to the solution. Upon addition of these, the solution became milky white and insoluble. It was stirred for 2 h. After every 30 minutes of stirring, 0.5 mmol of lipophilic Me2PzH (0.2402 g, 2.5 mmol) and equal portions of tri­ethyl­amine (0.11 ml, 0.79 mmol) were added. The solution slowly turned green and was further stirred for 12 h. It was then filtered and solvents were evaporated in vacuo to obtain a pale-green solid. Finally, the solid was recrystallized from methanol solution, which afforded blue crystals of 1. Crystal yield 45% [based on Ni(OOCCH3)2·4H2O], m.p. 212°C. ESI–MS: [M − 2H]+ 713.479; [M1 + Li]+ where [M1 = M-2(Me2PzH)-CH3CO] 487.309. FT–IR (KBr, ν, cm−1): 3122 (s), 3114 (s), 3000 (m), 2937 (s), 2738 (m), 2677 (s), 2015 (m, br), 1470 (m), 1307 (m), 1268 (m), 1407 (m), 1094 (s, br), 1032 (m), 941 (s), 898 (s), 855 (m), 811 (s), 624 (s), 554 (m).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸.

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2414314624008101/zl4073sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2414314624008101/zl4073Isup2.hkl

CCDC reference: 2346359

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

Dr Orbett Alexander, Department of Chemistry, University of Western Cape, South Africa, is thanked for crystallographic software assistance

full crystallographic data

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] Crystal data

[Ni2(C8H6N3)2(C2H3O2)2(C5H8N2)2]	F(000) = 744	
Mr = 716.09	Dx = 1.482 Mg m−3	
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å	
a = 11.1045 (7) Å	Cell parameters from 5987 reflections	
b = 9.1489 (6) Å	θ = 2.6–28.3°	
c = 15.8088 (11) Å	µ = 1.23 mm−1	
β = 92.210 (1)°	T = 100 K	
V = 1604.88 (18) Å3	Prism, blue	
Z = 2	0.12 × 0.10 × 0.10 mm	

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] Data collection

Bruker APEX diffractometer	Rint = 0.025	
Radiation source: sealed tube	θmax = 28.3°, θmin = 2.2°	
φ and ω scans	h = −14→14	
Absorption correction: multi-scan (SADABS; Krause et al., 2015	k = −12→12	
Tmin = 0.875, Tmax = 0.905	l = −21→14	
10468 measured reflections	4 standard reflections every 22 reflections	
3946 independent reflections	intensity decay: none	
3617 reflections with I > 2σ(I)		

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] Refinement

Refinement on F2	Primary atom site location: difference Fourier map	
Least-squares matrix: full	Secondary atom site location: inferred from neighbouring sites	
R[F2 > 2σ(F2)] = 0.030	Hydrogen site location: mixed	
wR(F2) = 0.079	H atoms treated by a mixture of independent and constrained refinement	
S = 1.04	w = 1/[σ2(Fo2) + (0.0457P)2 + 0.5264P] where P = (Fo2 + 2Fc2)/3	
3946 reflections	(Δ/σ)max < 0.001	
214 parameters	Δρmax = 0.44 e Å−3	
0 restraints	Δρmin = −0.27 e Å−3	

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] 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. All the non-hydrogen atoms were refined anisotropically using full-matrix least-square procedures while carbon bound hydrogen atoms were included in idealized positions and the methyl CH3 were allowed to rotate using a riding model. C—H bonds were constrained to 0.95 Å for aromatic C—H (Uiso(H) = 1.2 Ueq(C)) and 0.98 Å for CH3 [Uiso(H) = 1.5 Ueq(C)] units, respectively. The N—H proton was added from the difference Fourier map and refined with Uiso(H) = 1.2 Ueq(N).	

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

	x	y	z	Uiso*/Ueq		
C1	0.11107 (14)	0.40306 (17)	0.31691 (10)	0.0189 (3)		
H1	0.177134	0.357829	0.290855	0.023*		
C2	0.08185 (14)	0.54516 (18)	0.29476 (10)	0.0212 (3)		
H2	0.125431	0.595694	0.253272	0.025*		
C3	−0.01268 (15)	0.61225 (16)	0.33456 (11)	0.0213 (3)		
H3	−0.033162	0.710881	0.321898	0.026*		
C4	−0.07701 (13)	0.53426 (17)	0.39297 (9)	0.0184 (3)		
H4	−0.142463	0.578183	0.420430	0.022*		
C5	−0.04392 (13)	0.39056 (15)	0.41058 (9)	0.0152 (3)		
C6	−0.10578 (12)	0.29590 (16)	0.46928 (9)	0.0154 (3)		
C7	−0.21072 (13)	0.31154 (17)	0.51418 (10)	0.0192 (3)		
H7	−0.263572	0.393132	0.515024	0.023*		
C8	−0.21990 (13)	0.18053 (17)	0.55720 (10)	0.0191 (3)		
H8	−0.282715	0.156611	0.593911	0.023*		
C9	−0.31184 (15)	−0.1728 (2)	0.28848 (11)	0.0268 (4)		
H9A	−0.325502	−0.242347	0.241949	0.040*		
H9B	−0.377717	−0.101487	0.288064	0.040*		
H9C	−0.308875	−0.225503	0.342481	0.040*		
C10	−0.19552 (14)	−0.09537 (16)	0.27774 (10)	0.0195 (3)		
C11	−0.12922 (14)	−0.06840 (18)	0.20783 (10)	0.0206 (3)		
H11	−0.149648	−0.094806	0.150952	0.025*		
C12	−0.02518 (13)	0.00603 (17)	0.23726 (9)	0.0189 (3)		
C13	0.07636 (15)	0.0650 (2)	0.18861 (11)	0.0272 (4)		
H13A	0.101087	−0.008066	0.147390	0.041*		
H13B	0.144532	0.087654	0.227618	0.041*		
H13C	0.050240	0.154119	0.158824	0.041*		
C14	0.30155 (13)	0.17584 (17)	0.44170 (10)	0.0207 (3)		
C15	0.43466 (15)	0.2066 (2)	0.45627 (13)	0.0363 (4)		
H15A	0.473384	0.211363	0.401669	0.054*		
H15B	0.471550	0.128286	0.490694	0.054*		
H15C	0.445230	0.300123	0.485868	0.054*		
N1	0.05042 (11)	0.32623 (14)	0.37348 (8)	0.0158 (2)		
N2	−0.05658 (10)	0.16361 (14)	0.48562 (7)	0.0143 (2)		
N3	−0.12709 (11)	0.09133 (14)	0.53973 (8)	0.0157 (2)		
N4	−0.02724 (11)	0.02391 (14)	0.32099 (8)	0.0161 (2)		
N6	−0.13244 (11)	−0.03814 (14)	0.34435 (8)	0.0179 (3)		
O1	0.23062 (10)	0.19619 (12)	0.50069 (7)	0.0213 (2)		
O2	0.26366 (10)	0.12852 (12)	0.37041 (7)	0.0204 (2)		
Ni1	0.08662 (2)	0.11295 (2)	0.41577 (2)	0.01351 (7)		
H6	−0.1496 (16)	−0.046 (2)	0.3967 (12)	0.016*		

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] Atomic displacement parameters (Å2)

	U11	U22	U33	U12	U13	U23	
C1	0.0153 (7)	0.0217 (8)	0.0195 (7)	−0.0015 (5)	0.0013 (6)	0.0017 (6)	
C2	0.0190 (7)	0.0229 (8)	0.0218 (8)	−0.0039 (6)	0.0009 (6)	0.0061 (6)	
C3	0.0223 (8)	0.0164 (7)	0.0249 (8)	0.0001 (6)	−0.0022 (6)	0.0037 (6)	
C4	0.0164 (7)	0.0188 (7)	0.0198 (7)	0.0007 (5)	−0.0014 (6)	−0.0008 (6)	
C5	0.0139 (6)	0.0180 (7)	0.0136 (6)	−0.0012 (5)	−0.0024 (5)	−0.0015 (5)	
C6	0.0146 (6)	0.0171 (7)	0.0143 (6)	−0.0001 (5)	−0.0008 (5)	−0.0009 (5)	
C7	0.0171 (7)	0.0205 (8)	0.0200 (7)	0.0040 (6)	0.0022 (6)	0.0005 (6)	
C8	0.0152 (7)	0.0234 (8)	0.0189 (7)	0.0029 (6)	0.0037 (5)	0.0013 (6)	
C9	0.0225 (8)	0.0303 (9)	0.0271 (8)	−0.0091 (7)	−0.0076 (6)	0.0063 (7)	
C10	0.0183 (7)	0.0166 (7)	0.0229 (8)	−0.0001 (5)	−0.0054 (6)	0.0023 (6)	
C11	0.0212 (7)	0.0217 (7)	0.0183 (7)	0.0017 (6)	−0.0044 (6)	−0.0010 (6)	
C12	0.0180 (7)	0.0200 (7)	0.0186 (7)	0.0032 (6)	−0.0006 (6)	0.0015 (6)	
C13	0.0226 (8)	0.0396 (10)	0.0197 (8)	−0.0009 (7)	0.0034 (6)	−0.0011 (7)	
C14	0.0144 (7)	0.0201 (7)	0.0275 (8)	−0.0013 (5)	−0.0002 (6)	0.0065 (6)	
C15	0.0161 (8)	0.0456 (11)	0.0467 (11)	−0.0063 (7)	−0.0028 (7)	0.0064 (9)	
N1	0.0134 (6)	0.0186 (6)	0.0154 (6)	−0.0008 (5)	−0.0005 (4)	0.0009 (5)	
N2	0.0126 (5)	0.0166 (6)	0.0136 (6)	−0.0005 (5)	0.0013 (4)	0.0009 (5)	
N3	0.0129 (6)	0.0196 (6)	0.0147 (6)	0.0006 (5)	0.0023 (4)	0.0016 (5)	
N4	0.0134 (6)	0.0165 (6)	0.0183 (6)	0.0001 (4)	0.0011 (5)	0.0012 (5)	
N6	0.0162 (6)	0.0204 (6)	0.0172 (6)	−0.0022 (5)	−0.0003 (5)	0.0016 (5)	
O1	0.0176 (5)	0.0256 (6)	0.0205 (5)	−0.0023 (4)	−0.0009 (4)	0.0005 (4)	
O2	0.0164 (5)	0.0240 (6)	0.0210 (6)	0.0005 (4)	0.0043 (4)	0.0027 (4)	
Ni1	0.01067 (11)	0.01613 (12)	0.01377 (11)	−0.00014 (6)	0.00125 (7)	0.00074 (6)	

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] Geometric parameters (Å, º)

C1—N1	1.3393 (19)	C11—C12	1.405 (2)	
C1—C2	1.382 (2)	C11—H11	0.9500	
C1—H1	0.9500	C12—N4	1.3348 (19)	
C2—C3	1.388 (2)	C12—C13	1.490 (2)	
C2—H2	0.9500	C13—H13A	0.9800	
C3—C4	1.387 (2)	C13—H13B	0.9800	
C3—H3	0.9500	C13—H13C	0.9800	
C4—C5	1.390 (2)	C14—O1	1.2576 (19)	
C4—H4	0.9500	C14—O2	1.2641 (19)	
C5—N1	1.3547 (19)	C14—C15	1.514 (2)	
C5—C6	1.460 (2)	C14—Ni1	2.4738 (15)	
C6—N2	1.3488 (19)	C15—H15A	0.9800	
C6—C7	1.395 (2)	C15—H15B	0.9800	
C7—C8	1.384 (2)	C15—H15C	0.9800	
C7—H7	0.9500	N1—Ni1	2.0964 (13)	
C8—N3	1.3514 (19)	N2—N3	1.3541 (17)	
C8—H8	0.9500	N2—Ni1	2.0245 (12)	
C9—C10	1.489 (2)	N3—Ni1i	2.0409 (13)	
C9—H9A	0.9800	N4—N6	1.3626 (17)	
C9—H9B	0.9800	N4—Ni1	2.0884 (12)	
C9—H9C	0.9800	N6—H6	0.859 (18)	
C10—N6	1.3479 (19)	O1—Ni1	2.1848 (11)	
C10—C11	1.374 (2)	O2—Ni1	2.1232 (11)	
				
N1—C1—C2	122.95 (15)	O1—C14—Ni1	61.93 (8)	
N1—C1—H1	118.5	O2—C14—Ni1	59.12 (8)	
C2—C1—H1	118.5	C15—C14—Ni1	177.13 (13)	
C1—C2—C3	118.39 (14)	C14—C15—H15A	109.5	
C1—C2—H2	120.8	C14—C15—H15B	109.5	
C3—C2—H2	120.8	H15A—C15—H15B	109.5	
C4—C3—C2	119.50 (14)	C14—C15—H15C	109.5	
C4—C3—H3	120.2	H15A—C15—H15C	109.5	
C2—C3—H3	120.2	H15B—C15—H15C	109.5	
C3—C4—C5	118.75 (14)	C1—N1—C5	118.57 (13)	
C3—C4—H4	120.6	C1—N1—Ni1	127.31 (10)	
C5—C4—H4	120.6	C5—N1—Ni1	114.10 (10)	
N1—C5—C4	121.80 (14)	C6—N2—N3	108.63 (12)	
N1—C5—C6	114.08 (13)	C6—N2—Ni1	114.95 (10)	
C4—C5—C6	124.12 (14)	N3—N2—Ni1	135.91 (10)	
N2—C6—C7	109.55 (13)	C8—N3—N2	107.36 (12)	
N2—C6—C5	117.19 (13)	C8—N3—Ni1i	129.94 (10)	
C7—C6—C5	133.25 (14)	N2—N3—Ni1i	122.68 (9)	
C8—C7—C6	103.89 (13)	C12—N4—N6	105.39 (12)	
C8—C7—H7	128.1	C12—N4—Ni1	136.57 (11)	
C6—C7—H7	128.1	N6—N4—Ni1	118.01 (9)	
N3—C8—C7	110.57 (13)	C10—N6—N4	112.04 (13)	
N3—C8—H8	124.7	C10—N6—H6	126.3 (12)	
C7—C8—H8	124.7	N4—N6—H6	121.3 (12)	
C10—C9—H9A	109.5	C14—O1—Ni1	87.55 (9)	
C10—C9—H9B	109.5	C14—O2—Ni1	90.15 (9)	
H9A—C9—H9B	109.5	N2—Ni1—N3i	100.88 (5)	
C10—C9—H9C	109.5	N2—Ni1—N4	90.81 (5)	
H9A—C9—H9C	109.5	N3i—Ni1—N4	90.53 (5)	
H9B—C9—H9C	109.5	N2—Ni1—N1	79.39 (5)	
N6—C10—C11	106.28 (14)	N3i—Ni1—N1	177.68 (5)	
N6—C10—C9	121.53 (15)	N4—Ni1—N1	91.77 (5)	
C11—C10—C9	132.18 (15)	N2—Ni1—O2	157.80 (5)	
C10—C11—C12	106.26 (13)	N3i—Ni1—O2	89.05 (5)	
C10—C11—H11	126.9	N4—Ni1—O2	109.07 (5)	
C12—C11—H11	126.9	N1—Ni1—O2	89.92 (4)	
N4—C12—C11	110.03 (14)	N2—Ni1—O1	99.02 (5)	
N4—C12—C13	120.64 (14)	N3i—Ni1—O1	87.78 (5)	
C11—C12—C13	129.31 (14)	N4—Ni1—O1	170.18 (5)	
C12—C13—H13A	109.5	N1—Ni1—O1	89.91 (4)	
C12—C13—H13B	109.5	O2—Ni1—O1	61.24 (4)	
H13A—C13—H13B	109.5	N2—Ni1—C14	129.01 (5)	
C12—C13—H13C	109.5	N3i—Ni1—C14	87.58 (5)	
H13A—C13—H13C	109.5	N4—Ni1—C14	139.74 (5)	
H13B—C13—H13C	109.5	N1—Ni1—C14	90.48 (5)	
O1—C14—O2	121.02 (14)	O2—Ni1—C14	30.73 (5)	
O1—C14—C15	119.71 (15)	O1—Ni1—C14	30.52 (5)	
O2—C14—C15	119.27 (15)			
				
N1—C1—C2—C3	1.7 (2)	C7—C6—N2—N3	0.44 (16)	
C1—C2—C3—C4	−2.0 (2)	C5—C6—N2—N3	−178.96 (12)	
C2—C3—C4—C5	0.6 (2)	C7—C6—N2—Ni1	173.56 (10)	
C3—C4—C5—N1	1.2 (2)	C5—C6—N2—Ni1	−5.84 (16)	
C3—C4—C5—C6	−178.64 (14)	C7—C8—N3—N2	0.27 (17)	
N1—C5—C6—N2	5.98 (19)	C7—C8—N3—Ni1i	178.58 (10)	
C4—C5—C6—N2	−174.14 (13)	C6—N2—N3—C8	−0.43 (15)	
N1—C5—C6—C7	−173.25 (15)	Ni1—N2—N3—C8	−171.45 (11)	
C4—C5—C6—C7	6.6 (3)	C6—N2—N3—Ni1i	−178.89 (9)	
N2—C6—C7—C8	−0.27 (17)	Ni1—N2—N3—Ni1i	10.09 (18)	
C5—C6—C7—C8	179.01 (15)	C11—C12—N4—N6	−0.36 (17)	
C6—C7—C8—N3	0.00 (17)	C13—C12—N4—N6	178.19 (14)	
N6—C10—C11—C12	0.30 (17)	C11—C12—N4—Ni1	177.84 (11)	
C9—C10—C11—C12	−178.23 (17)	C13—C12—N4—Ni1	−3.6 (2)	
C10—C11—C12—N4	0.04 (18)	C11—C10—N6—N4	−0.55 (17)	
C10—C11—C12—C13	−178.35 (16)	C9—C10—N6—N4	178.17 (14)	
C2—C1—N1—C5	0.1 (2)	C12—N4—N6—C10	0.57 (16)	
C2—C1—N1—Ni1	−178.23 (11)	Ni1—N4—N6—C10	−178.03 (10)	
C4—C5—N1—C1	−1.6 (2)	O2—C14—O1—Ni1	1.96 (15)	
C6—C5—N1—C1	178.30 (13)	C15—C14—O1—Ni1	−177.31 (14)	
C4—C5—N1—Ni1	176.96 (11)	O1—C14—O2—Ni1	−2.01 (15)	
C6—C5—N1—Ni1	−3.15 (15)	C15—C14—O2—Ni1	177.26 (14)	

Symmetry code: (i) −x, −y, −z+1.

Bis[µ-3-(pyridin-2-yl)pyrazolato]bis[acetato(3,5-dimethyl-1H-pyrazole)nickel(II)] Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A	
N6—H6···N2	0.859 (18)	2.571 (18)	2.9931 (18)	111.4 (14)	
N6—H6···N3	0.859 (18)	2.591 (19)	3.3065 (18)	141.4 (16)	
N6—H6···O1i	0.859 (18)	2.332 (19)	3.0800 (17)	145.6 (16)	
C1—H1···O2	0.95	2.61	3.1281 (19)	115	
C2—H2···O2ii	0.95	2.37	3.2692 (19)	158	
C4—H4···O1iii	0.95	2.62	3.4696 (19)	149	
C9—H9C···O1i	0.98	2.61	3.426 (2)	141	
C13—H13B···O2	0.98	2.60	3.530 (2)	159	

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

Figure 1 The mol­ecule of 1 (with 50% displacement ellipsoids) with the unlabelled atoms related by crystallographic inversion symmetry (−x, −y, 1 − z). Intra­molecular C—H⋯O, N—H⋯O and N—H⋯N hydrogen bonds are shown as dashed lines.

Figure 2 Perspective view of 1 showing the intra- (red and black dotted lines) and inter­molecular C—H⋯O (pink dotted lines) and intra­molecular N—H⋯N (blue and black dotted lines) inter­actions with bond distances (several atoms were removed for clarity).

Table 1 Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A	
N6—H6⋯N2	0.859 (18)	2.571 (18)	2.9931 (18)	111.4 (14)	
N6—H6⋯N3	0.859 (18)	2.591 (19)	3.3065 (18)	141.4 (16)	
N6—H6⋯O1i	0.859 (18)	2.332 (19)	3.0800 (17)	145.6 (16)	
C1—H1⋯O2	0.95	2.61	3.1281 (19)	115	
C2—H2⋯O2ii	0.95	2.37	3.2692 (19)	158	
C4—H4⋯O1iii	0.95	2.62	3.4696 (19)	149	
C9—H9C⋯O1i	0.98	2.61	3.426 (2)	141	
C13—H13B⋯O2	0.98	2.60	3.530 (2)	159	
Symmetry codes: (i) ; (ii) ; (iii) .

Table 2 Experimental details

Crystal data	
Chemical formula	[Ni2(C8H6N3)2(C2H3O2)2(C5H8N2)2]	
M r	716.09	
Crystal system, space group	Monoclinic, P21/n	
Temperature (K)	100	
a, b, c (Å)	11.1045 (7), 9.1489 (6), 15.8088 (11)	
β (°)	92.210 (1)	
V (Å3)	1604.88 (18)	
Z	2	
Radiation type	Mo Kα	
μ (mm−1)	1.23	
Crystal size (mm)	0.12 × 0.10 × 0.10	
 	
Data collection	
Diffractometer	Bruker APEX	
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 ▸	
Tmin, Tmax	0.875, 0.905	
No. of measured, independent and observed [I > 2σ(I)] reflections	10468, 3946, 3617	
R int	0.025	
(sin θ/λ)max (Å−1)	0.667	
 	
Refinement	
R[F2 > 2σ(F2)], wR(F2), S	0.030, 0.079, 1.04	
No. of reflections	3946	
No. of parameters	214	
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement	
Δρmax, Δρmin (e Å−3)	0.44, −0.27	
Computer programs: SMART and SAINT (Bruker, 2012 ▸), SHELXT (Sheldrick, 2015a ▸), SHELXL2019/2 (Sheldrick, 2015b ▸), ORTEP-3 for Windows (Farrugia, 2012 ▸), DIAMOND (Brandenburg et al., 2014 ▸) and publCIF (Westrip, 2010 ▸).
==== Refs
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