Crystal structure of hexa­aqua­nickel(II) bis{2-[(5,6-di­hy­droxy-3-sul­fon­ato­quino­lin-1-ium-7-yl)oxy]acetate} dihydrate

Le Thi Hong, H.; Nguyen Thi Ngoc, V.; Tran Thi, D.; Nguyen Bich, N.; Van Meervelt, L.

doi:10.1107/S2056989015015662

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ISSN: 2056-9890

Volume 71| Part 9| September 2015| Pages 1105-1108

https://doi.org/10.1107/S2056989015015662

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Crystal structure of hexaaquanickel(II) bis{2-[(5,6-dihydroxy-3-sulfonatoquinolin-1-ium-7-yl)oxy]acetate} dihydrate

Hai Le Thi Hong,^a Vinh Nguyen Thi Ngoc,^a Da Tran Thi,^a Ngan Nguyen Bich ^a and Luc Van Meervelt ^b ^*

^aChemistry Department, Hanoi National University of Education, 136 - Xuan Thuy - Cau Giay, Hanoi, Vietnam, and ^bChemistry Department, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven (Heverlee), Belgium
^*Correspondence e-mail: luc.vanmeeervelt@chem.kuleuven.be

Edited by A. Van der Lee, Université de Montpellier II, France (Received 21 July 2015; accepted 20 August 2015; online 26 August 2015)

The asymmetric unit of the title compound, [Ni(H₂O)₆](C₁₁H₈NO₈S)₂·2H₂O, features a half-hexaaquanickel(II) complex cation with the Ni^II ion on an inversion center, one deprotonated 5,6-dihydroxy-3-sulfoquinolin-7-yloxyacetic acid (QOH) molecule appearing in its zwitterionic form and one lattice water molecule. The sulfonate group is disordered over two positions with occupancy factors of 0.655 (5) and 0.345 (5). The hexaaquanickel(II) cation interacts through hydrogen bonding with eight QOH molecules and two water molecules. The six-membered rings of quinoline show π–π stacking [centroid-to-centroid distances of 3.679 (2) Å and 3.714 (2) Å].

Keywords: crystal structure; quinoline; hydrogen bonding; π–π stacking; zwitterion.

CCDC reference: 1419884

1. Chemical context

Quinoline and its derivatives have been of great interest due to their interesting biochemical activities. Quinine, cinchonine, chloroquine, plasmoquine and acriquine, for instance, are known to be able to cure malaria (Foley & Tilley, 1998 ; Długosz & Duś, 1996 ; Nayyar et al., 2006 ). Complexes of quinoline-containing organic compounds with transition metals are also known for their wide variety of structures and profound biochemical activities which allow them to act as antibacterial and anti-Alzheimer agents (Deraeve et al., 2008 ) and as cures for many types of cancers such as cervical cancer, lung cancer and breast cancer (Yan et al., 2012 ; Daniel et al., 2004 ). These complexes, therefore, have been synthesized and investigated intensively (Kitanovic et al., 2014 ).

Recently, the new quinoline derivative 6-hydroxy-3-sulfoquinolin-7-yloxyacetic (Q) has been synthesized from eugenol and its antibacterial activities have been reported (Dinh et al., 2012 ). Here, we report the synthesis of 5,6-dihydroxy-3-sulfoquinolin-7-yloxyacetic acid (QOH). As quinoline rings are known to complex with metal ions, the formation of a complex between QOH and Ni^II was studied. The reaction product, however, could not be characterized unambiguously by IR or ¹H NMR spectroscopic methods. The spectroscopic data are different from those obtained for free QOH and in favour of a deprotonated carboxylic acid group, but give no indication about a possible complex formation. X-ray diffraction now shows that QOH is not complexing directly with Ni^II.

2. Structural commentary

The structure determination shows that the carboxyl group of QOH is deprotonated and the anion is present in its zwitterionic form (Fig. 1), which was also observed for Q (Dinh et al., 2012). The best plane through the quinoline ring (r.m.s. deviation = 0.009 Å) makes an angle of 15.29 (19)° with the carboxylate plane. The sulfonate group at the 3-position occurs in two orientations with occupancy factors of 0.655 (5) and 0.345 (5). QOH, however, is not acting as a ligand for Ni^II, which occurs as a hexaaqua complex. This [Ni(H₂O)₆]²⁺ is located about an inversion center and has an octahedral volume of 11.629 Å³ with Ni—O bond lengths between 2.034 (3) and 2.106 (2) Å.

Figure 1
The structures of the molecular components in the title compound with ellipsoids drawn at the 50% probability level. [Symmetry code: (iv) −x + 2, −y + 1, −z + 2.]

3. Supramolecular features

The hexaaquanickel(II) cation plays the role of glue in the crystal packing. In total, it interacts with eight QOH moieties and two water molecules through O—H⋯O and N—H⋯O hydrogen bonding (Table 1, Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2A⋯O27ⁱ	0.84	1.86	2.694 (3)	175
O2—H2B⋯O29ⁱⁱ	0.88 (4)	1.85 (4)	2.718 (5)	169 (4)
O3—H3A⋯O8ⁱⁱⁱ	0.84	2.14	2.829 (5)	139
O3—H3B⋯O6^iv	0.76 (5)	2.05 (5)	2.691 (5)	142 (5)
O4—H4A⋯O28ⁱ	0.84	1.73	2.569 (4)	173
O4—H4B⋯O6	0.81 (4)	1.95 (4)	2.709 (5)	156 (4)
N14—H14⋯O4^v	0.81 (4)	2.00 (4)	2.809 (4)	174 (3)
O22—H22⋯O8^vi	0.84	2.03	2.779 (5)	147
O23—H23⋯O29ⁱ	0.84	1.85	2.625 (5)	153
O29—H29A⋯O27ⁱ	0.83 (4)	1.82 (4)	2.630 (4)	165 (4)
O29—H29B⋯O7ⁱⁱⁱ	0.83 (4)	2.23 (4)	2.959 (6)	148 (5)
C13—H13⋯O7^vii	0.95	2.24	3.166 (6)	165
C17—H17⋯O22^vi	0.95	2.43	3.354 (4)	166
C18—H18⋯O28^viii	0.95	2.40	3.345 (5)	176
Symmetry codes: (i) -x+2, -y+2, -z+1; (ii) -x+2, -y+2, -z+2; (iii) x+1, y, z; (iv) -x+2, -y+1, -z+2; (v) x, y+1, z; (vi) -x+1, -y+1, -z+1; (vii) -x+1, -y+2, -z+2; (viii) -x+2, -y+3, -z+1.

Figure 2
Partial packing diagram of the title compound, showing the hydrogen-bonding interactions (red dotted lines, see Table 1

for details).

Furthermore, π–π stacking between the quinoline rings results in the formation of inversion dimers [Cg1⋯Cg1^ix = 3.679 (2) Å, Cg1⋯Cg2^ix = 3.714 (2) Å; Cg1 and Cg2 are the centroids of the rings C12/C13/N14/C15–C17 and C15/C16/C18–C21, respectively; symmetry code: (ix) −x + 1, −y + 2, −z + 1; Fig. 3].

Figure 3
Partial packing diagram of the title compound, showing π–π interactions between quinoline rings (grey dotted lines; Cg1 and Cg2 are the centroids of rings C12/C13/N14/C15–C17 and C15/C16/C18–C21, respectively). [Symmetry code: (ix) −x + 1, −y + 2, −z + 1.]

Lattice water molecule O29 interacts with the carboxylate (O27) and hydroxyl (O23) groups of a neighboring QOH molecule and furthermore with the sulfonate group (O7) of a second QOH molecule and the hexaaqua complex (O2). Whereas hydroxyl group O23—H23 only interacts with water molecule O29, the second hydroxyl group O22—H22 is involved in the formation of another type of inversion dimers through C—H⋯O hydrogen bonding and interacts with a sulfonate group (O8) (Table 1, Fig. 2).

4. Database survey

A search of the Cambridge Structural Database (Version 5.36; last update May 2015; Groom & Allen, 2014 ) for quinoline derivatives gives 3040 hits of which 529 are protonated at the nitrogen atom. Searching for quinoline derivatives bearing a sulfonate group results in 30 hits for substitution at the 5-position, 3 hits at the 8-position, 2 hits at the 7-position and two structures have a sulfonate group at the 3-position [CSD refcodes BAPBOK (Skrzypek & Suwinska, 2002 ) and HIVHUQ (Skrzypek & Suwinska, 2007 )]. As for the title compound, these two structures occur in the zwitterionic form, but do not show disorder in the sulfonate group.

5. Synthesis and crystallization

Starting from eugenol, a main constituent of Ocimum sanctum L. oil, the quinoline derivative 6-hydroxy-3-sulfoquinolin-7-yloxyacetic acid (Q) was synthesized and further transformed to 5,6-dihydroxy-3-sulfoquinolin-7-yloxyacetic acid (QOH) according to a procedure described by Dinh et al. (2012).

A solution containing NiCl₂·6H₂O (0.262 g, 1.1 mmol) in ethanol–water (10 mL; 1:1 v/v) was added dropwise to a solution of QOH (0.630 g, 2 mmol) in ethanol–water (15 mL, 1:1 v/v). The obtained solution was stirred for three hours, at 313–323 K, during reflux. A few days later, the green–yellow precipitate was collected by filtration, washed consecutively with ethanol and diethyl ether and dried in vacuo. The obtained crystals are soluble in water and DMSO, but only slightly soluble in ethanol, acetone and chloroform. The yield was 65%. Single crystals suitable for X-ray investigation were obtained by slow evaporation from a ethanol–water (1:1 v/v) solution at room temperature. IR (Impack-410 Nicolet spectrometer, KBr, cm⁻¹): 3420 (ν_OH); 3080, 2918 (ν_C-H); 1620 (ν_COOas); 1426(ν_COOs); 1528 (ν_C=Cring or ν_C=N); 466 (ν_Ni-O). ¹H NMR (Bruker Avance 500 MHz, d₆-DMSO): δ 8.74 (1H, s, Ar), 8.17 (1H, s, Ar), 7.2 (1H, s, Ar), 4.64 (2H, s, CH₂); (Bruker Avance 500 MHz, D₂O): δ 9.26 (1H, s, Ar), 9.01 (1H, s, Ar), 7.01 (1H, s, Ar), 4.80 (2H, s, CH₂).

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. H atoms H2B, H3B, H4B, H14, H29A and H29B were located in difference Fourier maps. All other H atoms were placed at idealized positions and refined in riding mode, with C—H distances of 0.95 (aromatic) and 0.99 Å (methylene), and O—H distances of 0.84 Å. The H atoms of water molecule O29 were refined with an O—H distance restraint of 0.85 Å and H⋯H distance restraint of 1.39 Å. For all H atoms, U_iso(H) values were assigned as 1.2U_eq of the parent atoms (1.5U_eq for H22 and H23). The SO₃ group is disordered over two positions, the occupancy ratio refines to 0.655 (5):0.345 (5) for part 1 (O6, O7, 08) and part 2 (O9, O10, O11), respectively.

Table 2
Experimental details

Crystal data
Chemical formula	[Ni(H₂O)₆](C₁₁H₈NO₈S)₂·2H₂O
M_r	831.31
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	100
a, b, c (Å)	8.1632 (5), 8.2829 (6), 11.8492 (8)
α, β, γ (°)	102.316 (6), 102.250 (6), 93.003 (6)
V (Å³)	760.91 (9)
Z	1
Radiation type	Mo Kα
μ (mm⁻¹)	0.88
Crystal size (mm)	0.3 × 0.2 × 0.15

Data collection
Diffractometer	Agilent SuperNova (single source at offset, Eos detector)
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2012 )
T_min, T_max	0.781, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	8135, 3071, 2513
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.625

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.047, 0.125, 1.09
No. of reflections	3071
No. of parameters	283
No. of restraints	213
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.48, −0.84
Computer programs: CrysAlis PRO (Agilent, 2012), XS and SHELXL (Sheldrick, 2008 ) and OLEX2 (Dolomanov et al., 2009 ).

Supporting information

CCDC reference: 1419884

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989015015662/vn2096sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989015015662/vn2096Isup2.hkl

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); program(s) used to solve structure: XS (Sheldrick, 2008); program(s) used to refine structure: SHELXL (Sheldrick, 2008); molecular graphics: Olex2 (Dolomanov et al., 2009); software used to prepare material for publication: Olex2 (Dolomanov et al., 2009).

Hexaaquanickel(II) bis(5,6-dihydroxy-3-sulfoquinolin-7-yloxyacetic acid) dihydrate top

Crystal data top

[Ni(H₂O)₆](C₁₁H₈NO₈S)₂·2H₂O	Z = 1
M_r = 831.31	F(000) = 430
Triclinic, P1	D_x = 1.814 Mg m⁻³
a = 8.1632 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.2829 (6) Å	Cell parameters from 2769 reflections
c = 11.8492 (8) Å	θ = 3.4–28.9°
α = 102.316 (6)°	µ = 0.88 mm⁻¹
β = 102.250 (6)°	T = 100 K
γ = 93.003 (6)°	Block, yellow
V = 760.91 (9) Å³	0.3 × 0.2 × 0.15 mm

Data collection top

Agilent SuperNova (single source at offset, Eos detector) diffractometer	3071 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	2513 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.025
Detector resolution: 15.9631 pixels mm^-1	θ_max = 26.4°, θ_min = 2.8°
ω scans	h = −10→10
Absorption correction: multi-scan (CrysAlisPro; Agilent, 2012)	k = −10→10
T_min = 0.781, T_max = 1.000	l = −14→14
8135 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.047	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.125	w = 1/[σ²(F_o²) + (0.0452P)² + 1.8778P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max < 0.001
3071 reflections	Δρ_max = 0.48 e Å⁻³
283 parameters	Δρ_min = −0.84 e Å⁻³
213 restraints

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ni1	1.0000	0.5000	1.0000	0.02176 (19)
O2	1.0198 (3)	0.7442 (3)	0.9941 (2)	0.0260 (6)
H2A	0.9996	0.7520	0.9230	0.031*
H2B	0.952 (5)	0.803 (5)	1.031 (4)	0.031*
O3	1.1954 (4)	0.4632 (3)	0.9188 (2)	0.0313 (6)
H3A	1.1967	0.5296	0.8744	0.038*
H3B	1.265 (6)	0.413 (6)	0.943 (4)	0.038*
O4	0.8307 (3)	0.4307 (3)	0.8328 (2)	0.0249 (5)
H4A	0.8770	0.4558	0.7811	0.030*
H4B	0.748 (5)	0.478 (5)	0.840 (4)	0.030*
S5	0.48964 (11)	0.73394 (10)	0.85461 (7)	0.0223 (2)
O6	0.6221 (5)	0.6546 (6)	0.9048 (4)	0.0389 (13)	0.655 (5)
O7	0.4212 (6)	0.8513 (5)	0.9337 (4)	0.0368 (12)	0.655 (5)
O8	0.3539 (5)	0.6107 (5)	0.7699 (3)	0.0321 (11)	0.655 (5)
O9	0.6135 (9)	0.7895 (10)	0.9785 (6)	0.029 (2)	0.345 (5)
O10	0.3282 (9)	0.7681 (11)	0.8587 (7)	0.031 (2)	0.345 (5)
O11	0.5153 (9)	0.5620 (9)	0.8093 (6)	0.0245 (18)	0.345 (5)
C12	0.5705 (4)	0.8478 (4)	0.7634 (3)	0.0213 (7)
C13	0.6412 (4)	1.0124 (4)	0.8098 (3)	0.0213 (7)
H13	0.6409	1.0658	0.8891	0.026*
N14	0.7090 (4)	1.0941 (4)	0.7428 (2)	0.0212 (6)
H14	0.744 (5)	1.190 (5)	0.774 (3)	0.025*
C15	0.7152 (4)	1.0268 (4)	0.6280 (3)	0.0196 (7)
C16	0.6429 (4)	0.8599 (4)	0.5784 (3)	0.0201 (7)
C17	0.5717 (4)	0.7727 (4)	0.6481 (3)	0.0208 (7)
H17	0.5240	0.6610	0.6158	0.025*
C18	0.7910 (4)	1.1199 (4)	0.5627 (3)	0.0210 (7)
H18	0.8376	1.2317	0.5962	0.025*
C19	0.7951 (4)	1.0426 (4)	0.4485 (3)	0.0209 (7)
C20	0.7240 (5)	0.8766 (4)	0.3960 (3)	0.0240 (7)
C21	0.6498 (4)	0.7865 (4)	0.4600 (3)	0.0231 (7)
O22	0.5812 (4)	0.6280 (3)	0.4145 (2)	0.0337 (6)
H22	0.6086	0.5913	0.3501	0.051*
O23	0.7252 (4)	0.7973 (3)	0.2843 (2)	0.0374 (7)
H23	0.7859	0.8556	0.2560	0.056*
O24	0.8641 (3)	1.1125 (3)	0.3741 (2)	0.0254 (5)
C25	0.9285 (4)	1.2848 (4)	0.4117 (3)	0.0242 (7)
H25A	1.0146	1.3044	0.4872	0.029*
H25B	0.8362	1.3544	0.4246	0.029*
C26	1.0064 (4)	1.3300 (5)	0.3152 (3)	0.0271 (8)
O27	1.0256 (3)	1.2204 (3)	0.2309 (2)	0.0341 (6)
O28	1.0496 (4)	1.4828 (4)	0.3317 (2)	0.0424 (8)
O29	1.1564 (6)	1.0664 (4)	0.8667 (3)	0.0543 (10)
H29A	1.088 (5)	0.986 (5)	0.829 (4)	0.065*
H29B	1.242 (4)	1.041 (6)	0.908 (4)	0.065*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.0296 (4)	0.0192 (3)	0.0192 (3)	−0.0028 (2)	0.0124 (3)	0.0049 (2)
O2	0.0364 (15)	0.0224 (12)	0.0229 (13)	0.0015 (11)	0.0139 (11)	0.0064 (10)
O3	0.0401 (16)	0.0279 (14)	0.0321 (15)	−0.0007 (11)	0.0206 (13)	0.0089 (11)
O4	0.0304 (14)	0.0262 (13)	0.0218 (12)	−0.0041 (10)	0.0120 (11)	0.0091 (10)
S5	0.0271 (5)	0.0246 (4)	0.0205 (4)	−0.0015 (3)	0.0129 (3)	0.0105 (3)
O6	0.030 (2)	0.059 (3)	0.043 (3)	0.008 (2)	0.0156 (19)	0.036 (2)
O7	0.061 (3)	0.030 (2)	0.031 (2)	0.004 (2)	0.034 (2)	0.0087 (18)
O8	0.037 (2)	0.039 (2)	0.0203 (19)	−0.0153 (18)	0.0114 (16)	0.0079 (16)
O9	0.030 (4)	0.039 (4)	0.020 (3)	−0.011 (3)	0.004 (3)	0.018 (3)
O10	0.021 (3)	0.048 (5)	0.036 (5)	0.004 (3)	0.012 (3)	0.027 (4)
O11	0.029 (4)	0.026 (3)	0.021 (4)	−0.007 (3)	0.007 (3)	0.011 (3)
C12	0.0217 (16)	0.0264 (16)	0.0218 (16)	0.0010 (13)	0.0103 (13)	0.0134 (13)
C13	0.0234 (17)	0.0279 (17)	0.0168 (15)	0.0005 (13)	0.0095 (13)	0.0100 (13)
N14	0.0248 (15)	0.0224 (14)	0.0181 (14)	−0.0035 (12)	0.0079 (11)	0.0065 (11)
C15	0.0195 (16)	0.0250 (16)	0.0176 (15)	0.0006 (13)	0.0072 (12)	0.0096 (12)
C16	0.0199 (16)	0.0255 (16)	0.0177 (15)	0.0013 (13)	0.0066 (12)	0.0090 (13)
C17	0.0203 (16)	0.0243 (16)	0.0206 (16)	−0.0007 (13)	0.0066 (13)	0.0100 (13)
C18	0.0208 (16)	0.0268 (17)	0.0193 (15)	−0.0012 (13)	0.0067 (13)	0.0125 (13)
C19	0.0218 (16)	0.0251 (16)	0.0227 (16)	0.0039 (13)	0.0110 (13)	0.0144 (13)
C20	0.0330 (19)	0.0274 (17)	0.0165 (15)	0.0046 (14)	0.0114 (14)	0.0093 (13)
C21	0.0301 (18)	0.0247 (16)	0.0173 (15)	−0.0015 (14)	0.0085 (13)	0.0086 (13)
O22	0.0572 (18)	0.0255 (13)	0.0210 (13)	−0.0090 (12)	0.0187 (12)	0.0044 (10)
O23	0.072 (2)	0.0257 (13)	0.0224 (13)	−0.0002 (13)	0.0269 (13)	0.0076 (11)
O24	0.0367 (14)	0.0249 (12)	0.0214 (12)	0.0000 (10)	0.0168 (10)	0.0108 (10)
C25	0.0257 (18)	0.0297 (18)	0.0201 (16)	−0.0045 (14)	0.0080 (14)	0.0110 (14)
C26	0.0219 (17)	0.041 (2)	0.0224 (17)	−0.0031 (15)	0.0059 (14)	0.0172 (15)
O27	0.0420 (16)	0.0423 (15)	0.0316 (14)	0.0108 (12)	0.0238 (12)	0.0211 (12)
O28	0.0592 (19)	0.0433 (16)	0.0254 (14)	−0.0226 (14)	0.0169 (13)	0.0088 (12)
O29	0.113 (3)	0.0303 (16)	0.0419 (19)	0.0166 (17)	0.057 (2)	0.0147 (14)

Geometric parameters (Å, º) top

Ni1—O2	2.038 (2)	N14—C15	1.368 (4)
Ni1—O2ⁱ	2.038 (2)	C15—C16	1.423 (5)
Ni1—O3ⁱ	2.034 (3)	C15—C18	1.409 (4)
Ni1—O3	2.034 (3)	C16—C17	1.399 (4)
Ni1—O4ⁱ	2.106 (2)	C16—C21	1.419 (5)
Ni1—O4	2.106 (2)	C17—H17	0.9500
O2—H2A	0.8400	C18—H18	0.9500
O2—H2B	0.88 (4)	C18—C19	1.375 (5)
O3—H3A	0.8400	C19—C20	1.419 (5)
O3—H3B	0.76 (5)	C19—O24	1.351 (4)
O4—H4A	0.8400	C20—C21	1.374 (4)
O4—H4B	0.81 (4)	C20—O23	1.348 (4)
S5—O6	1.387 (4)	C21—O22	1.350 (4)
S5—O7	1.423 (4)	O22—H22	0.8400
S5—O8	1.500 (4)	O23—H23	0.8400
S5—O9	1.556 (7)	O24—C25	1.436 (4)
S5—O10	1.371 (7)	C25—H25A	0.9900
S5—O11	1.454 (7)	C25—H25B	0.9900
S5—C12	1.779 (3)	C25—C26	1.522 (4)
C12—C13	1.399 (5)	C26—O27	1.242 (5)
C12—C17	1.377 (5)	C26—O28	1.258 (5)
C13—H13	0.9500	O29—H29A	0.827 (19)
C13—N14	1.331 (4)	O29—H29B	0.826 (19)
N14—H14	0.81 (4)

O2ⁱ—Ni1—O2	180.0	N14—C13—C12	119.9 (3)
O2—Ni1—O4	92.67 (10)	N14—C13—H13	120.0
O2ⁱ—Ni1—O4ⁱ	92.67 (10)	C13—N14—H14	115 (3)
O2ⁱ—Ni1—O4	87.33 (10)	C13—N14—C15	123.9 (3)
O2—Ni1—O4ⁱ	87.33 (10)	C15—N14—H14	121 (3)
O3ⁱ—Ni1—O2	90.14 (11)	N14—C15—C16	117.3 (3)
O3—Ni1—O2	89.86 (11)	N14—C15—C18	120.9 (3)
O3ⁱ—Ni1—O2ⁱ	89.86 (11)	C18—C15—C16	121.9 (3)
O3—Ni1—O2ⁱ	90.14 (11)	C17—C16—C15	119.3 (3)
O3ⁱ—Ni1—O3	180.0	C17—C16—C21	122.3 (3)
O3—Ni1—O4ⁱ	90.58 (11)	C21—C16—C15	118.3 (3)
O3ⁱ—Ni1—O4ⁱ	89.43 (11)	C12—C17—C16	120.4 (3)
O3—Ni1—O4	89.42 (11)	C12—C17—H17	119.8
O3ⁱ—Ni1—O4	90.57 (11)	C16—C17—H17	119.8
O4ⁱ—Ni1—O4	180.0	C15—C18—H18	121.3
Ni1—O2—H2A	109.5	C19—C18—C15	117.5 (3)
Ni1—O2—H2B	113 (3)	C19—C18—H18	121.3
H2A—O2—H2B	109.2	C18—C19—C20	122.2 (3)
Ni1—O3—H3A	109.5	O24—C19—C18	125.3 (3)
Ni1—O3—H3B	119 (4)	O24—C19—C20	112.4 (3)
H3A—O3—H3B	129.1	C21—C20—C19	120.0 (3)
Ni1—O4—H4A	109.5	O23—C20—C19	123.8 (3)
Ni1—O4—H4B	106 (3)	O23—C20—C21	116.2 (3)
H4A—O4—H4B	113.9	C20—C21—C16	120.1 (3)
O6—S5—O7	117.0 (3)	O22—C21—C16	117.5 (3)
O6—S5—O8	111.0 (3)	O22—C21—C20	122.4 (3)
O6—S5—C12	106.2 (2)	C21—O22—H22	109.5
O7—S5—O8	111.2 (3)	C20—O23—H23	109.5
O7—S5—C12	105.9 (2)	C19—O24—C25	118.6 (3)
O8—S5—C12	104.47 (18)	O24—C25—H25A	110.1
O9—S5—C12	104.9 (3)	O24—C25—H25B	110.1
O10—S5—O9	112.3 (5)	O24—C25—C26	108.1 (3)
O10—S5—O11	117.2 (5)	H25A—C25—H25B	108.4
O10—S5—C12	110.5 (3)	C26—C25—H25A	110.1
O11—S5—O9	105.7 (4)	C26—C25—H25B	110.1
O11—S5—C12	105.3 (3)	O27—C26—C25	120.6 (3)
C13—C12—S5	120.3 (2)	O27—C26—O28	125.5 (3)
C17—C12—S5	120.4 (3)	O28—C26—C25	113.9 (3)
C17—C12—C13	119.2 (3)	H29A—O29—H29B	114 (3)
C12—C13—H13	120.0

S5—C12—C13—N14	176.7 (3)	C15—C16—C21—O22	179.8 (3)
S5—C12—C17—C16	−176.8 (3)	C15—C18—C19—C20	1.0 (5)
O6—S5—C12—C13	−90.9 (4)	C15—C18—C19—O24	−179.3 (3)
O6—S5—C12—C17	85.9 (4)	C16—C15—C18—C19	−0.9 (5)
O7—S5—C12—C13	34.2 (4)	C17—C12—C13—N14	−0.2 (5)
O7—S5—C12—C17	−149.0 (3)	C17—C16—C21—C20	−178.7 (3)
O8—S5—C12—C13	151.7 (3)	C17—C16—C21—O22	1.5 (5)
O8—S5—C12—C17	−31.5 (4)	C18—C15—C16—C17	179.0 (3)
O9—S5—C12—C13	−37.7 (4)	C18—C15—C16—C21	0.6 (5)
O9—S5—C12—C17	139.1 (4)	C18—C19—C20—C21	−0.9 (5)
O10—S5—C12—C13	83.5 (5)	C18—C19—C20—O23	179.7 (3)
O10—S5—C12—C17	−99.7 (5)	C18—C19—O24—C25	−4.8 (5)
O11—S5—C12—C13	−149.1 (4)	C19—C20—C21—C16	0.6 (5)
O11—S5—C12—C17	27.7 (4)	C19—C20—C21—O22	−179.6 (3)
C12—C13—N14—C15	−0.2 (5)	C19—O24—C25—C26	177.2 (3)
C13—C12—C17—C16	0.0 (5)	C20—C19—O24—C25	174.9 (3)
C13—N14—C15—C16	0.6 (5)	C21—C16—C17—C12	178.8 (3)
C13—N14—C15—C18	−179.1 (3)	O23—C20—C21—C16	180.0 (3)
N14—C15—C16—C17	−0.8 (5)	O23—C20—C21—O22	−0.2 (5)
N14—C15—C16—C21	−179.2 (3)	O24—C19—C20—C21	179.4 (3)
N14—C15—C18—C19	178.9 (3)	O24—C19—C20—O23	0.0 (5)
C15—C16—C17—C12	0.5 (5)	O24—C25—C26—O27	−9.2 (5)
C15—C16—C21—C20	−0.4 (5)	O24—C25—C26—O28	172.1 (3)

Symmetry code: (i) −x+2, −y+1, −z+2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O27ⁱⁱ	0.84	1.86	2.694 (3)	175
O2—H2B···O29ⁱⁱⁱ	0.88 (4)	1.85 (4)	2.718 (5)	169 (4)
O3—H3A···O8^iv	0.84	2.14	2.829 (5)	139
O3—H3B···O6ⁱ	0.76 (5)	2.05 (5)	2.691 (5)	142 (5)
O4—H4A···O28ⁱⁱ	0.84	1.73	2.569 (4)	173
O4—H4B···O6	0.81 (4)	1.95 (4)	2.709 (5)	156 (4)
N14—H14···O4^v	0.81 (4)	2.00 (4)	2.809 (4)	174 (3)
O22—H22···O8^vi	0.84	2.03	2.779 (5)	147
O23—H23···O29ⁱⁱ	0.84	1.85	2.625 (5)	153
O29—H29A···O27ⁱⁱ	0.83 (4)	1.82 (4)	2.630 (4)	165 (4)
O29—H29B···O7^iv	0.83 (4)	2.23 (4)	2.959 (6)	148 (5)
C13—H13···O7^vii	0.95	2.24	3.166 (6)	165
C17—H17···O22^vi	0.95	2.43	3.354 (4)	166
C18—H18···O28^viii	0.95	2.40	3.345 (5)	176

Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) −x+2, −y+2, −z+1; (iii) −x+2, −y+2, −z+2; (iv) x+1, y, z; (v) x, y+1, z; (vi) −x+1, −y+1, −z+1; (vii) −x+1, −y+2, −z+2; (viii) −x+2, −y+3, −z+1.

Acknowledgements

The authors thank VLIR-UOS (project ZEIN2014Z182) for financial support and the Hercules Foundation for supporting the purchase of the diffractometer through project AKUL/09/0035.

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