Crystal structure of a nickel compound comprising two nickel(II) complexes with different ligand environments: [Ni(tren)(H2O)2][Ni(H2O)6](SO4)2

González Nieves, K.; Piñero Cruz, D.M.

doi:10.1107/S2056989020001358

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 76| Part 3| March 2020| Pages 314-317

https://doi.org/10.1107/S2056989020001358

Open

access

Crystal structure of a nickel compound comprising two nickel(II) complexes with different ligand environments: [Ni(tren)(H₂O)₂][Ni(H₂O)₆](SO₄)₂

Karilys González Nieves ^a ^* and Dalice M. Piñero Cruz ^b

^aDepartment of Natural Sciences, University of Puerto Rico, Carolina Campus, 2100 Avenida Sur, Carolina, PR 00987, Puerto Rico, and ^bDepartment of Chemistry, University of Puerto Rico, Rio Piedras Campus, Ponce de Leon Avenue, San Juan, PR 00931, Puerto Rico
^*Correspondence e-mail: karilys.gonzalez@upr.edu

Edited by C. Massera, Università di Parma, Italy (Received 24 May 2019; accepted 30 January 2020; online 6 February 2020)

The title compound, diaqua[tris(2-aminoethyl)amine]nickel(II) hexaaquanickel(II) bis(sulfate), [Ni(C₆H₁₈N₄)(H₂O)₂][Ni(H₂O)₆](SO₄)₂ or [Ni(tren)(H₂O)₂][Ni(H₂O)₆](SO₄)₂, consists of two octahedral nickel complexes within the same unit cell. These metal complexes are formed from the reaction of [Ni(H₂O)₆](SO₄) and the ligand tris(2-aminoethyl)amine (tren). The crystals of the title compound are purple, different from those of the starting complex [Ni(H₂O)₆](SO₄), which are turquoise. The reaction was performed both in a 1:1 and 1:2 metal–ligand molar ratio, always yielding the co-precipitation of the two types of crystals. The asymmetric unit of the title compound, which crystallizes in the space group Pnma, consists of two half Ni^II complexes and a sulfate counter-anion. The mononuclear cationic complex [Ni(tren)(H₂O)₂]²⁺ comprises an Ni ion, the tren ligand and two water molecules, while the mononuclear complex [Ni(H₂O)₆]²⁺ consists of another Ni ion surrounded by six coordinated water molecules. The [Ni(tren)(H₂O)₂] and [Ni(H₂O)₆] subunits are connected to the SO₄²⁻ counter-anions through hydrogen bonding, thus consolidating the crystal structure.

Keywords: crystal structure; nickel complexes; tren; tripodal ligand; hydrogen bonding.

CCDC reference: 1911584

1. Chemical context

Tris(2-aminoethyl)amine (tren) has been used extensively as an ancillary tripodal ligand for capping transition metals to form mononuclear and polynuclear complexes. The tren ligand has the capacity to chelate metal ions through its central tertiary amine and through its three terminal amine groups in a spider-like conformation, leaving one or two positions available for additional ligand coordination (Marzotto et al., 1993 ; Albertin et al., 1975 ; Blackman, 2005 ; Brines et al., 2007 ). Metal complexes with a variety of ligands in which also tren is coordinating to the metal center have been proposed for applications in catalysis (Ruffin et al., 2017 ), sensors, and as precursors of bioinorganic reactions (Sakai et al., 1996 ). For instance, Ni(tren) complexes have been proposed for applications in biological systems (Salam & Aoki, 2001 ) or as a model to study enantioselective synthesis or asymmetric catalysis (Rao et al., 2009 ), and as coordination polymers in magnetism, electrical conductivity and ion exchange (Park et al., 2001 ; Tanase et al., 1996 ). [Ni(tren)(H₂O)₂] was reported previously (Chen et al., 2001 ; Pedersen et al., 2014 ); however, to our knowledge, this is the first report of it co-crystallizing with the hexaaquo nickel complex [Ni(H₂O)₆](SO₄).

2. Structural commentary

Fig. 1 shows the molecular structure of the title compound, which crystallizes in the space group Pnma. Its asymmetric unit comprises two half Ni^II complexes and a sulfate counter-anion. Each Ni complex shows a different ligand environment: (i) the mononuclear cationic complex [Ni(tren)(H₂O)₂]²⁺ includes Ni1, the tren ligand and two water molecules; (ii) the mononuclear complex [Ni(H₂O)₆]²⁺ consists of Ni2 surrounded by six coordinated water molecules.

Figure 1
View of the molecular structure of the title compound with displacement ellipsoids drawn at the 20% probability level and labeling scheme for the symmetry-independent atoms. The CH₂ hydrogen atoms have been omitted for clarity. The symmetry operations generating the equivalent atoms are 1 − x, 1 − y, 2 − z and x, $[{1\over 2}]$ − y, z for [Ni(H₂O)₆]²⁺ and [Ni(tren)(H₂O)₂]²⁺, respectively.

Ni1 exhibits an octahedral geometry of the type N₄O₂, with the central N1 atom of the tren ligand occupying one of the axial positions and atoms N2, N3 and N2ⁱ occupying three of the equatorial positions [symmetry code: (i) x, −y + $[{1\over 2}]$ , z]. The remaining two positions, one axial (O2) and one equatorial (O1), are occupied by two oxygen atoms from the two water molecules. The bond lengths are similar for the Ni1—N bonds that are trans to oxygen atoms; for instance, Ni1—N1_ax is 2.064 (2) Å and Ni1—N3_eq is 2.069 (2) Å; a longer bond distance is observed between Ni1—N2_eq, 2.122 (2), which is trans by symmetry to another nitrogen atom, N2ⁱ. The nickel–oxygen bond length is shorter for Ni1—O2_ax at 2.094 (2) Å, in comparison to Ni1—O1_eq, which is 2.140 (2) Å. The N3 and C3 atoms of the tren ligand lie on a mirror plane perpendicular to [010]. This results in a symmetry-induced disorder of the N3/C4/C3 fragment. The octahedral geometry around the Ni1 ion is reflected by the angles N1—Ni1—O2 = 178.42 (8)°, N2—Ni1—N2ⁱ = 164.74 (9)°, and N3—Ni1—O1 = 177.27 (8)°.

The Ni2 ion of the mononuclear complex [Ni(H₂O)₆]²⁺ also shows an octahedral geometry. In the asymmetric unit, the atom Ni2 sits on an inversion center on a screw axis along the b-axis direction. The Ni2—O_water bond lengths with O3, O4 and O5 range between 2.051 (1) and 2.074 (1) Å, respectively, with angles of 180° due to symmetry.

3. Supramolecular features

The crystal structure of the title compound is consolidated through intermolecular hydrogen bonding between the water molecules from the [Ni(tren)(H₂O)₂] complex, the sulfate oxygen atoms and the water molecules from the [Ni(H₂O)₆] complex (Fig. 2 and Table 1). In particular, the two water molecules of [Ni(tren)(H₂O)₂] form O1—H1⋯O8ⁱ and O2—H2⋯O6 hydrogen bonds of 2.05 (2) and 1.96 (2) Å respectively, involving two neighboring SO₄²⁻ anions [symmetry code: (i) x + $[{1\over 2}]$ , y, −z + $[{3\over 2}]$ ). The [Ni(H₂O)₆] complex is hydrogen bonded to adjacent SO₄²⁻ anions through O3—H3E⋯O9ⁱⁱ, O3—H3F⋯O7ⁱ, O4—H4C⋯O6, O4—H4D⋯O8ⁱ, O5—H5B⋯O7, O5—H5A⋯O7ⁱⁱⁱ contacts [symmetry codes: (ii) −x + $[{1\over 2}]$ , −y + 1, z − $[{1\over 2}]$ ; (iii) −x + $[{1\over 2}]$ , −y + 1, z + $[{1\over 2}]$ ]. These hydrogen-bond distances range from 1.905 (15) to 2.047 (18) Å. Additional weak hydrogen bonds are formed between the hydrogen atoms from the primary amine groups of the tren ligand and the sulfate oxygen atoms.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O8ⁱ	0.78 (2)	2.05 (2)	2.8212 (16)	172 (2)
O2—H2⋯O6	0.81 (2)	1.96 (2)	2.7342 (15)	162 (3)
O3—H3E⋯O9ⁱⁱ	0.81 (2)	1.94 (2)	2.731 (2)	167 (2)
O3—H3F⋯O7ⁱ	0.85 (2)	2.05 (2)	2.8403 (18)	155 (2)
O4—H4C⋯O6	0.83 (2)	1.91 (2)	2.7249 (18)	171 (2)
O4—H4D⋯O8ⁱ	0.83 (2)	1.95 (2)	2.7810 (18)	179 (2)
O5—H5A⋯O7ⁱⁱⁱ	0.88	2.02	2.8125 (19)	150
O5—H5B⋯O7	0.88	1.95	2.7826 (17)	160
Symmetry codes: (i) $[x+{\script{1\over 2}}, y, -z+{\script{3\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, -y+1, z-{\script{1\over 2}}]$ ; (iii) $[-x+{\script{1\over 2}}, -y+1, z+{\script{1\over 2}}]$ .

Figure 2
The hydrogen-bonding network (cyan dotted lines) in the title compound. Symmetry codes: (i) x + $[{1\over 2}]$ , y, −z + $[{3\over 2}]$ ; (ii) −x + $[{1\over 2}]$ , −y + 1, z − $[{1\over 2}]$ ; (iii) −x + $[{1\over 2}]$ , −y + 1, z + $[{1\over 2}]$ .

4. Database survey

A search for tris(2-aminoethyl)aminenickel complexes in the Cambridge Structural Database (CSD version 5.38, updated February 2019; Groom et al., 2016 ) yielded 222 hits. Among these results, 124 hits contained the ligand tris(2-aminoethyl)amine capping the nickel ion, along with other types of ligands on the remaining coordination sites. Only two hits contain the diaqua[tris(2-aminoethyl)amine]nickel(II) complex, [Ni(tren)(H₂O)₂] (LUMVIY; Chen et al., 2001; TIYQAT; Tanase et al., 1996). More precisely, the asymmetric unit in LUMVIY comprises the [Ni(tren)(H₂O)₂]²⁺ cation with two independent halves of a 1,5-naphthalenedisulfonate (1,5nds) ligand as counter-anion. A common feature of this structure with the title compound is the hydrogen bond network formed between the water molecules on the Ni(tren) motif with the counter anions. However, in the title compound, also the hydrogen atoms on the primary amine groups form hydrogen bonds with the sulfate anions, albeit quite weak. In TIYQAT, sulfate anions act as counter-ions for the [Ni(tren)(H₂O)₂]²⁺ complex, and uncoordinated water molecules are included in the crystal lattice. The angle between the Ni center and the two oxygen atoms from the coordinated water molecules are 86.52 (5)° (O7—Ni1—O8) and 86.9 (4)° (O5—Ni1—O6) for LUMVIY and TIYQAT, respectively. The corresponding angle O2—Ni—O1 in the tittle compound has a value of 88.70 (8)°, which is in good agreement with the reported values. The title compound is the first example of a crystal structure of [Ni(tren)(H₂O)₂]²⁺ co-crystallizing with the [Ni(H₂O)₆]²⁺ complex.

5. Synthesis and crystallization

The synthesis of the title compound is summarized in the reaction scheme shown in Fig. 3. NiSO₄·6H₂O and tris(2-aminoethyl)amine (tren) were used without further purification. A methanolic solution of NiSO₄·6H₂O (0.0265 g, 0.1 mmol) was added slowly to a tren (0.0146 g, 0.1 mmol) solution (4 mL MeOH) at room temperature. The resulting solution was stirred for two h and it changed color from light green to purple. The solution was then filtered through celite and evaporated under reduced pressure. Single crystals of the title compound were obtained by vapor diffusion of methanol into 2-propanol. In the crystallization process, two types of crystal were formed: the starting reagent hexahydrate nickel (II) complex (turquoise crystals) and the nickel(II) tren complex (purple crystals, Fig. 4). The reaction was performed both in a 1:1 and 1:2 metal–ligand molar ratio, always yielding the title compound. IR data: 3265 (m), 3171 (m), 2937 (w), 2891 (w), 1607 (m), 1472 (w) 1338 (w), 1054 (s), 984 (m), 885 (m), 750 (w), 685 (w).

Figure 3
Reaction scheme for the synthesis of [Ni(tren)(H₂O)₂][Ni(H₂O)₆](SO₄)_2.

Figure 4
Crystallization of [Ni(tren)(H₂O)₂][Ni(H₂O)₆](SO₄)₂ and [Ni(H₂O)₆]SO₄ in the same reaction vial.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. H atoms were included in geometrically calculated positions for the alkyl and amine groups using a riding model: C—H = 0.97 Å and N—H = 0.89 Å with U_iso(H) =1.2U_eq(C, N). The hydrogen atoms of the water molecules were located from the difference-Fourier map; they were refined freely in the case of O1 and O2, with a DFIX of 0.85 (2) Å and U_iso(H) =1.5U_eq(O) in the case of O3 and O4, and riding with O—H = 0.88 Å and U_iso(H) =1.5U_eq(O) in the case of O5.

Table 2
Experimental details

Crystal data
Chemical formula	[Ni(C₆H₁₈N₄)(H₂O)₂][Ni(H₂O)₆](SO₄)₂
M_r	599.91
Crystal system, space group	Orthorhombic, Pnma
Temperature (K)	293
a, b, c (Å)	11.8937 (1), 21.3933 (2), 8.4468 (1)
V (Å³)	2149.25 (4)
Z	4
Radiation type	Cu Kα
μ (mm⁻¹)	4.76
Crystal size (mm)	0.28 × 0.21 × 0.09

Data collection
Diffractometer	Rigaku Oxford Diffraction SuperNova, Single source at offset/far, HyPix3000
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2015 $[Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ )
T_min, T_max	0.353, 0.661
No. of measured, independent and observed [I > 2σ(I)] reflections	17858, 2044, 1996
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.605

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.023, 0.063, 1.12
No. of reflections	2044
No. of parameters	173
No. of restraints	8
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.37, −0.35
Computer programs: CrysAlis PRO (Rigaku OD, 2015 $[Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ ), olex2.solve (Bourhis et al., 2015 ), SHELXL2016 (Sheldrick, 2015 ) and OLEX2 (Dolomanov et al., 2009 ).

The N3 and C3 atoms of the tren ligand lie on a mirror plane perpendicular to [010]. This results in a symmetry-induced disorder of the N3/C4/C3 fragment.

Supporting information

CCDC reference: 1911584

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989020001358/xi2016sup1.cif

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Rigaku OD, 2015); cell refinement: CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: olex2.solve (Bourhis et al., 2015); program(s) used to refine structure: SHELXL2016 (Sheldrick, 20156); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Diaqua[tris(2-aminoethyl)amine]nickel(II) hexaaquanickel(II) bis(sulfate) top

Crystal data top

[Ni(C₆H₁₈N₄)(H₂O)₂][Ni(H₂O)₆](SO₄)₂	D_x = 1.854 Mg m⁻³
M_r = 599.91	Cu Kα radiation, λ = 1.54184 Å
Orthorhombic, Pnma	Cell parameters from 14387 reflections
a = 11.8937 (1) Å	θ = 3.7–68.8°
b = 21.3933 (2) Å	µ = 4.76 mm⁻¹
c = 8.4468 (1) Å	T = 293 K
V = 2149.25 (4) Å³	Block, clear violet
Z = 4	0.28 × 0.21 × 0.09 mm
F(000) = 1256

Data collection top

Rigaku Oxford Diffraction SuperNova, Single source at offset/far, HyPix3000 diffractometer	1996 reflections with I > 2σ(I)
ω scans	R_int = 0.023
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015)	θ_max = 68.9°, θ_min = 4.1°
T_min = 0.353, T_max = 0.661	h = −14→14
17858 measured reflections	k = −25→25
2044 independent reflections	l = −10→10

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.023	All H-atom parameters refined
wR(F²) = 0.063	w = 1/[σ²(F_o²) + (0.0312P)² + 1.2986P] where P = (F_o² + 2F_c²)/3
S = 1.12	(Δ/σ)_max < 0.001
2044 reflections	Δρ_max = 0.37 e Å⁻³
173 parameters	Δρ_min = −0.35 e Å⁻³
8 restraints	Extinction correction: SHELXL2016 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: dual	Extinction coefficient: 0.00044 (5)

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ni1	0.31517 (3)	0.250000	0.58049 (4)	0.01987 (12)
O1	0.49430 (15)	0.250000	0.5573 (2)	0.0285 (4)
H1	0.523 (2)	0.2795 (11)	0.592 (3)	0.042 (7)*
O2	0.33527 (17)	0.250000	0.8268 (2)	0.0315 (4)
H2	0.304 (2)	0.2795 (11)	0.867 (3)	0.056 (8)*
N1	0.29062 (16)	0.250000	0.3386 (2)	0.0237 (4)
N2	0.32729 (13)	0.34830 (7)	0.55183 (18)	0.0291 (3)
H2A	0.275056	0.367313	0.609911	0.035*
H2B	0.394537	0.361563	0.583583	0.035*
N3	0.14137 (18)	0.250000	0.5913 (3)	0.0330 (5)
H3A	0.116429	0.211740	0.613150	0.040*	0.5
H3B	0.118127	0.275722	0.667351	0.040*	0.5
C1	0.34686 (17)	0.30780 (9)	0.2826 (2)	0.0336 (4)
H1A	0.327506	0.315269	0.172689	0.040*
H1B	0.427761	0.302752	0.289509	0.040*
C2	0.31074 (17)	0.36314 (9)	0.3821 (2)	0.0362 (4)
H2C	0.354856	0.399608	0.353854	0.043*
H2D	0.232177	0.372476	0.362353	0.043*
C3	0.1684 (2)	0.250000	0.3008 (3)	0.0344 (6)
H3C	0.145952	0.208172	0.269741	0.041*	0.5
H3D	0.154994	0.277594	0.211689	0.041*	0.5
C4	0.0975 (3)	0.27067 (19)	0.4375 (5)	0.0384 (10)	0.5
H4A	0.092804	0.315934	0.437065	0.046*	0.5
H4B	0.022018	0.254369	0.424014	0.046*	0.5
Ni2	0.500000	0.500000	1.000000	0.02058 (12)
O3	0.46413 (12)	0.51163 (6)	0.76229 (15)	0.0337 (3)
H3E	0.4398 (19)	0.5433 (9)	0.723 (2)	0.051*
H3F	0.5103 (18)	0.4984 (11)	0.693 (2)	0.051*
O4	0.47512 (11)	0.40611 (6)	0.96546 (16)	0.0291 (3)
H4C	0.4079 (14)	0.3972 (9)	0.956 (3)	0.044*
H4D	0.5051 (17)	0.3935 (9)	0.883 (2)	0.044*
O5	0.33269 (10)	0.51618 (6)	1.05567 (15)	0.0309 (3)
H5A	0.320545	0.510448	1.156884	0.046*
H5B	0.288625	0.490680	1.003402	0.046*
S1	0.14894 (3)	0.39419 (2)	0.92733 (4)	0.02016 (12)
O6	0.26060 (10)	0.36508 (6)	0.92041 (16)	0.0339 (3)
O7	0.15935 (10)	0.46130 (5)	0.88353 (15)	0.0297 (3)
O8	0.07525 (11)	0.36247 (6)	0.81077 (16)	0.0341 (3)
O9	0.10124 (13)	0.38801 (6)	1.08500 (15)	0.0408 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.0238 (2)	0.0199 (2)	0.0160 (2)	0.000	−0.00128 (15)	0.000
O1	0.0262 (9)	0.0235 (9)	0.0357 (10)	0.000	−0.0058 (8)	0.000
O2	0.0465 (11)	0.0277 (10)	0.0203 (9)	0.000	−0.0002 (8)	0.000
N1	0.0257 (10)	0.0280 (10)	0.0172 (9)	0.000	−0.0027 (8)	0.000
N2	0.0326 (8)	0.0234 (7)	0.0313 (8)	0.0027 (6)	−0.0018 (6)	−0.0024 (6)
N3	0.0275 (11)	0.0381 (12)	0.0335 (12)	0.000	0.0076 (9)	0.000
C1	0.0396 (10)	0.0397 (11)	0.0214 (9)	−0.0057 (8)	0.0016 (8)	0.0098 (8)
C2	0.0439 (10)	0.0254 (9)	0.0392 (11)	−0.0015 (8)	−0.0059 (9)	0.0115 (8)
C3	0.0316 (13)	0.0423 (15)	0.0292 (13)	0.000	−0.0114 (11)	0.000
C4	0.0252 (16)	0.046 (2)	0.044 (2)	0.0077 (14)	−0.0074 (15)	−0.0045 (16)
Ni2	0.0226 (2)	0.0206 (2)	0.0185 (2)	−0.00029 (15)	−0.00085 (15)	−0.00050 (15)
O3	0.0442 (8)	0.0364 (7)	0.0206 (6)	0.0102 (6)	−0.0007 (6)	0.0031 (5)
O4	0.0297 (6)	0.0264 (6)	0.0312 (7)	−0.0037 (5)	0.0030 (6)	−0.0036 (5)
O5	0.0258 (6)	0.0392 (7)	0.0279 (6)	−0.0029 (5)	0.0000 (5)	−0.0073 (6)
S1	0.0224 (2)	0.0187 (2)	0.0193 (2)	−0.00018 (14)	−0.00065 (14)	0.00073 (14)
O6	0.0255 (6)	0.0294 (7)	0.0468 (8)	0.0032 (5)	−0.0021 (6)	−0.0059 (6)
O7	0.0369 (7)	0.0207 (6)	0.0316 (7)	−0.0039 (5)	−0.0083 (5)	0.0049 (5)
O8	0.0378 (7)	0.0280 (6)	0.0364 (7)	−0.0079 (5)	−0.0130 (6)	0.0017 (5)
O9	0.0594 (9)	0.0344 (7)	0.0284 (7)	0.0040 (7)	0.0168 (6)	0.0024 (6)

Geometric parameters (Å, º) top

Ni1—O1	2.1395 (18)	C2—H2D	0.9700
Ni1—O2	2.0940 (19)	C3—H3C	0.9700
Ni1—N1	2.0640 (19)	C3—H3Cⁱ	0.9700
Ni1—N2	2.1217 (15)	C3—H3D	0.9700
Ni1—N2ⁱ	2.1217 (15)	C3—H3Dⁱ	0.9700
Ni1—N3	2.069 (2)	C3—C4	1.496 (4)
O1—H1	0.78 (2)	C4—H4A	0.9700
O1—H1ⁱ	0.78 (2)	C4—H4B	0.9700
O2—H2	0.81 (2)	Ni2—O3ⁱⁱ	2.0678 (13)
O2—H2ⁱ	0.81 (2)	Ni2—O3	2.0678 (13)
N1—C1	1.483 (2)	Ni2—O4ⁱⁱ	2.0511 (13)
N1—C1ⁱ	1.483 (2)	Ni2—O4	2.0511 (13)
N1—C3	1.488 (3)	Ni2—O5	2.0739 (12)
N2—H2A	0.8900	Ni2—O5ⁱⁱ	2.0739 (12)
N2—H2B	0.8900	O3—H3E	0.808 (15)
N2—C2	1.481 (2)	O3—H3F	0.851 (15)
N3—H3Aⁱ	0.8900	O4—H4C	0.826 (15)
N3—H3A	0.8900	O4—H4D	0.830 (15)
N3—H3B	0.8900	O5—H5A	0.8756
N3—H3Bⁱ	0.8900	O5—H5B	0.8759
N3—C4	1.468 (4)	S1—O6	1.4679 (13)
C1—H1A	0.9700	S1—O7	1.4878 (12)
C1—H1B	0.9700	S1—O8	1.4826 (12)
C1—C2	1.514 (3)	S1—O9	1.4537 (13)
C2—H2C	0.9700

O2—Ni1—O1	88.70 (8)	C1—C2—H2D	109.8
O2—Ni1—N2	96.06 (4)	H2C—C2—H2D	108.2
O2—Ni1—N2ⁱ	96.06 (4)	N1—C3—H3Cⁱ	109.06 (3)
N1—Ni1—O1	92.87 (8)	N1—C3—H3C	109.1
N1—Ni1—O2	178.42 (8)	N1—C3—H3Dⁱ	109.07 (10)
N1—Ni1—N2ⁱ	84.07 (4)	N1—C3—H3D	109.1
N1—Ni1—N2	84.07 (4)	N1—C3—C4	112.6 (2)
N1—Ni1—N3	84.39 (9)	H3C—C3—H3Cⁱ	134.6
N2ⁱ—Ni1—O1	85.52 (4)	H3Cⁱ—C3—H3Dⁱ	107.8
N2—Ni1—O1	85.52 (4)	H3C—C3—H3D	107.8
N2ⁱ—Ni1—N2	164.74 (9)	H3C—C3—H3Dⁱ	35.2
N3—Ni1—O1	177.27 (8)	H3D—C3—H3Cⁱ	35.2
N3—Ni1—O2	94.03 (9)	H3D—C3—H3Dⁱ	75.0
N3—Ni1—N2ⁱ	94.18 (4)	C4—C3—H3C	109.1
N3—Ni1—N2	94.18 (4)	C4—C3—H3Cⁱ	77.37 (16)
Ni1—O1—H1ⁱ	113.6 (18)	C4—C3—H3Dⁱ	133.34 (17)
Ni1—O1—H1	113.6 (18)	C4—C3—H3D	109.1
H1—O1—H1ⁱ	109 (3)	N3—C4—H3Aⁱ	34.21 (10)
Ni1—O2—H2	111.3 (19)	N3—C4—C3	113.2 (3)
Ni1—O2—H2ⁱ	111.3 (19)	N3—C4—H4A	108.9
H2—O2—H2ⁱ	103 (4)	N3—C4—H4B	108.9
C1ⁱ—N1—Ni1	104.58 (11)	C3—C4—H3Aⁱ	136.9 (3)
C1—N1—Ni1	104.58 (11)	C3—C4—H4A	108.9
C1—N1—C1ⁱ	113.0 (2)	C3—C4—H4B	108.9
C1—N1—C3	111.85 (12)	H4A—C4—H3Aⁱ	76.7
C1ⁱ—N1—C3	111.85 (12)	H4A—C4—H4B	107.8
C3—N1—Ni1	110.50 (15)	H4B—C4—H3Aⁱ	109.6
Ni1—N2—H2A	110.0	O3ⁱⁱ—Ni2—O3	180.0
Ni1—N2—H2B	110.0	O3ⁱⁱ—Ni2—O5	89.88 (5)
H2A—N2—H2B	108.4	O3—Ni2—O5	90.12 (5)
C2—N2—Ni1	108.29 (11)	O3ⁱⁱ—Ni2—O5ⁱⁱ	90.12 (5)
C2—N2—H2A	110.0	O3—Ni2—O5ⁱⁱ	89.88 (5)
C2—N2—H2B	110.0	O4—Ni2—O3ⁱⁱ	92.87 (5)
Ni1—N3—H3A	110.0	O4ⁱⁱ—Ni2—O3	92.87 (5)
Ni1—N3—H3Aⁱ	110.008 (12)	O4—Ni2—O3	87.13 (5)
Ni1—N3—H3Bⁱ	110.01 (5)	O4ⁱⁱ—Ni2—O3ⁱⁱ	87.13 (5)
Ni1—N3—H3B	110.0	O4ⁱⁱ—Ni2—O4	180.0
H3A—N3—H3Aⁱ	133.8	O4ⁱⁱ—Ni2—O5ⁱⁱ	93.28 (5)
H3A—N3—H3B	108.4	O4ⁱⁱ—Ni2—O5	86.72 (5)
H3A—N3—H3Bⁱ	34.7	O4—Ni2—O5ⁱⁱ	86.72 (5)
H3Aⁱ—N3—H3Bⁱ	108.4	O4—Ni2—O5	93.28 (5)
H3B—N3—H3Aⁱ	34.7	O5—Ni2—O5ⁱⁱ	180.00 (7)
H3B—N3—H3Bⁱ	76.4	Ni2—O3—H3E	124.9 (15)
C4—N3—Ni1	108.42 (19)	Ni2—O3—H3F	119.7 (15)
C4—N3—H3A	110.0	H3E—O3—H3F	103 (2)
C4—N3—H3Aⁱ	77.77 (16)	Ni2—O4—H4C	112.3 (14)
C4—N3—H3B	110.0	Ni2—O4—H4D	112.1 (14)
C4—N3—H3Bⁱ	135.62 (17)	H4C—O4—H4D	105 (2)
N1—C1—H1A	109.6	Ni2—O5—H5A	110.9
N1—C1—H1B	109.6	Ni2—O5—H5B	110.8
N1—C1—C2	110.31 (15)	H5A—O5—H5B	107.8
H1A—C1—H1B	108.1	O6—S1—O7	108.92 (8)
C2—C1—H1A	109.6	O6—S1—O8	108.32 (8)
C2—C1—H1B	109.6	O8—S1—O7	109.01 (7)
N2—C2—C1	109.38 (14)	O9—S1—O6	110.55 (9)
N2—C2—H2C	109.8	O9—S1—O7	110.37 (8)
N2—C2—H2D	109.8	O9—S1—O8	109.63 (8)
C1—C2—H2C	109.8

Ni1—N1—C1—C2	−48.90 (17)	N1—C3—C4—N3	−35.8 (3)
Ni1—N1—C3—C4	18.68 (18)	C1ⁱ—N1—C1—C2	−162.01 (12)
Ni1—N2—C2—C1	−27.22 (18)	C1—N1—C3—C4	−97.4 (2)
Ni1—N3—C4—C3	34.2 (3)	C1ⁱ—N1—C3—C4	134.7 (2)
N1—C1—C2—N2	52.2 (2)	C3—N1—C1—C2	70.7 (2)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O8ⁱⁱⁱ	0.78 (2)	2.05 (2)	2.8212 (16)	172 (2)
O2—H2···O6	0.81 (2)	1.96 (2)	2.7342 (15)	162 (3)
O3—H3E···O9^iv	0.81 (2)	1.94 (2)	2.731 (2)	167 (2)
O3—H3F···O7ⁱⁱⁱ	0.85 (2)	2.05 (2)	2.8403 (18)	155 (2)
O4—H4C···O6	0.83 (2)	1.91 (2)	2.7249 (18)	171 (2)
O4—H4D···O8ⁱⁱⁱ	0.83 (2)	1.95 (2)	2.7810 (18)	179 (2)
O5—H5A···O7^v	0.88	2.02	2.8125 (19)	150
O5—H5B···O7	0.88	1.95	2.7826 (17)	160

Symmetry codes: (iii) x+1/2, y, −z+3/2; (iv) −x+1/2, −y+1, z−1/2; (v) −x+1/2, −y+1, z+1/2.

Acknowledgements

We are grateful to the Department of Natural Science at UPR Carolina Campus (Department of Education, grant No. PO31S130068; however, those contents do not necessarily represent the policy of the Department of Education, and you should not assume endorsement by the Federal Government) and the University of Puerto Rico's Molecular Sciences Research Center for the use of the Rigaku XTLab SuperNova diffractometer. Special thanks to Dr Indranil Chakraborty for consultation on the final refinement of the structure.

Funding information

This material is based upon work supported by the National Science Foundation under grant No. 1626103. This study was supported by an Institutional Development Award (IDeA) INBRE grant No. P20GM103475 from the National Institute of General Medical Sciences (NIGMS), a component of the National Institutes of Health (NIH), and the Bioinformatics Research Core of the INBRE. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of NIGMS or NIH.

References

Albertin, G., Bordignon, E. & Orio, A. A. (1975). Inorg. Chem. 14, 1411–1413. CrossRef CAS Web of Science Google Scholar
Blackman, A. G. (2005). Polyhedron, 24, 1–39. Web of Science CrossRef CAS Google Scholar
Bourhis, L. J., Dolomanov, O. V., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2015). Acta Cryst. A71, 59–75. Web of Science CrossRef IUCr Journals Google Scholar
Brines, L. M., Shearer, J., Fender, J. K., Schweitzer, D., Shoner, S. C., Barnhart, D., Kaminsky, W., Lovell, S. & Kovacs, J. A. (2007). Inorg. Chem. 46, 9267–9277. Web of Science CSD CrossRef PubMed CAS Google Scholar
Chen, C., Cai, J., Feng, X. & Chen, X. (2001). J. Chem. Crystallogr. 31, 271–280. Web of Science CSD CrossRef CAS Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Marzotto, A., Clemente, D. A., Ciccarese, A. & Valle, G. (1993). J. Crystallogr. Spectrosc. Res. 23, 119–131. CSD CrossRef CAS Web of Science Google Scholar
Park, H. W., Sung, S. M., Min, K. S., Bang, H. & Suh, M. P. (2001). Eur. J. Inorg. Chem. pp. 2857–2863. CrossRef Google Scholar
Pedersen, K. S., Bendix, J. & Clérac, R. (2014). Chem. Commun. 50, 4396–4415. Web of Science CrossRef CAS Google Scholar
Rao, S. A., Pal, A., Ghosh, R. & Das, S. K. (2009). Inorg. Chem. 48, 10476. Web of Science CrossRef Google Scholar
Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England. Google Scholar
Ruffin, H., Boussambe, G. N. M., Roisnel, T., Dorcet, V., Boitrel, B. & Le Gac, S. (2017). J. Am. Chem. Soc. 139, 13847–13857. Web of Science CSD CrossRef CAS PubMed Google Scholar
Sakai, K., Yamada, Y. & Tsubomura, T. (1996). Inorg. Chem. 35, 3163–3172. CSD CrossRef PubMed CAS Web of Science Google Scholar
Salam, A. Md. & Aoki, K. (2001). Inorg. Chim. Acta, 314, 71–82. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Tanase, T., Doi, M., Nouchi, R., Kato, M., Sato, Y., Ishida, K., Kobayashi, K., Sakurai, T., Yamamoto, Y. & Yano, S. (1996). Inorg. Chem. 35, 4848–4857. CSD CrossRef PubMed CAS Web of Science Google Scholar

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.