Bis(4-amino­pyridinium) hexa­aqua­nickel(II) bis­(sulfate)

Sahbani, T.; Smirani Sta, W.; Rzaigui, M.

doi:10.1107/S1600536813032558

metal-organic compounds

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ISSN: 2056-9890

Volume 70| Part 1| January 2014| Page m6

https://doi.org/10.1107/S1600536813032558

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Bis(4-aminopyridinium) hexaaquanickel(II) bis(sulfate)

Thameur Sahbani,^a Wajda Smirani Sta ^a ^* and Mohamed Rzaigui ^a

^aLaboratoire de Chimie des Matériaux, Faculté des Sciences de Bizerte, 7021 Zarzouna Bizerte, Tunisia
^*Correspondence e-mail: wajda_sta@yahoo.fr

(Received 25 November 2013; accepted 29 November 2013; online 7 December 2013)

In the title compound, (C₅H₇N₂)₂[Ni(H₂O)₆](SO₄)₂, the Ni^II cation is located on an inversion centre and is coordinated by six aqua ligands in a slightly distorted octahedral coordination environment. The [Ni(H₂O)₆]²⁺ ions are connected through an extensive network of O—H⋯O hydrogen bonds to sulfate anions, leading to the formation of layers parallel to (001). The 4-aminopyridinium cations are located between these layers and are connected to the anionic framework by N—H⋯O hydrogen bonds. Weak π–π interactions between the pyridine rings, with a centroid–centroid distance of 3.754 (9) Å, provide additional stability to the crystal packing.

CCDC reference: 974558

Related literature

For applications of metal sulfate complexes, see: Rekik et al. (2008 ). For clinical background to 4-aminopyridine, see: Judge & Bever (2006 ); Schwid et al. (1997 ); Strupp et al. (2004 ). For related compounds, see: Anderson et al. (2005 ); Hajlaoui et al. (2011 ); Quah et al. (2010 ); Rotondo et al. (2009 ).

Experimental

Crystal data

(C₅H₇N₂)₂[Ni(H₂O)₆](SO₄)₂
M_r = 549.18
Triclinic, $[P \overline 1]$
a = 6.212 (2) Å
b = 7.015 (3) Å
c = 12.422 (2) Å
α = 100.61 (3)°
β = 99.26 (2)°
γ = 99.57 (2)°
V = 514.3 (3) Å³
Z = 1
Ag Kα radiation
λ = 0.56085 Å
μ = 0.64 mm⁻¹
T = 293 K
0.30 × 0.20 × 0.20 mm

Data collection

Enraf–Nonius TurboCAD-4 diffractometer
5919 measured reflections
5022 independent reflections
3986 reflections with I > 2σ(I)
R_int = 0.014
2 standard reflections every 120 min intensity decay: 5%

Refinement

R[F² > 2σ(F²)] = 0.038
wR(F²) = 0.097
S = 1.11
5022 reflections
174 parameters
6 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.75 e Å⁻³
Δρ_min = −1.06 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H1⋯O2ⁱ	0.86	2.43	3.102 (2)	136
N2—H1⋯O3ⁱⁱ	0.86	2.23	2.983 (2)	147
O1—H1O1⋯O7ⁱ	0.82 (2)	2.03 (2)	2.8231 (16)	163 (2)
O1—H2O1⋯O5ⁱⁱⁱ	0.86 (2)	1.82 (2)	2.6741 (16)	172 (2)
O2—H1O2⋯O4^iv	0.83 (2)	1.90 (2)	2.6952 (17)	161 (2)
O2—H2O2⋯O7ⁱ	0.84 (2)	1.95 (2)	2.7480 (16)	159 (2)
N1—H6⋯O4ⁱ	0.80 (3)	2.17 (3)	2.957 (2)	173 (3)
N1—H7⋯O5^v	0.86 (3)	2.55 (3)	3.153 (2)	129 (2)
N1—H7⋯O6^v	0.86 (3)	2.15 (3)	2.998 (2)	170 (2)
O3—H103⋯O5^vi	0.77 (2)	1.96 (2)	2.7072 (15)	164 (2)
O3—H203⋯O7^vii	0.815 (19)	1.876 (19)	2.6682 (15)	164 (2)
Symmetry codes: (i) -x+1, -y, -z+1; (ii) x+1, y, z+1; (iii) x-1, y-1, z-1; (iv) -x+1, -y+1, -z+1; (v) -x+2, -y, -z+1; (vi) x-1, y, z-1; (vii) x, y, z-1.

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ); software used to prepare material for publication: WinGX (Farrugia, 2012).

Supporting information

CCDC reference: 974558

Crystal structure: contains datablocks I, cad4. DOI: https://doi.org/10.1107/S1600536813032558/wm2787sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813032558/wm2787Isup2.hkl

checkCIF report

Comment top

4-Aminopyridine (fampridine) is clinically used in the treatment of the Lambert-Eaton myasthenic syndrome and of multiple sclerosis. It prolongs action potentials by blocking potassium channels, thereby increases transmitter release at the neuromuscular junction (Judge & Bever, 2006; Schwid et al., 1997; Strupp et al., 2004). The combination of this amine with sulfuric acid leads to the formation of bis(4-aminopyridinium) sulfate monohydrate (Quah et al., 2010). In general, sulfates combined with transition metal and organic groups can lead to interesting materials as model compounds of ferroelectric and ferroelastic domains, but also to potentially applicable compounds with interesting magnetic properties (Rekik et al., 2008). For this reasons, we focused to study the crystal structure of the title compound, (C₅H₇N₂)₂[Ni(H₂O)₆](SO₄)₂, (I).

The crystal structure of compound (I) has an asymmetric unit consisting of one half of the cationic complex [Ni(H₂O)₆]²⁺, an uncoordinating sulfate anion, and one 4-aminopyridinium cation, C₅H₇N₂²⁺ (Fig. 1). The Ni(II) ion, located on an inversion centre, exhibits a distorted octahedral coordination environment with Ni–O distances ranging from 2.0388 (11) to 2.0701 (12) Å. The values of O—Ni—O angles are between 86.04 (5) and 180.00 (7). These values agree with those for other [Ni(H₂O)₆]²⁺ groups (Hajlaoui et al., 2011).

A proton transfer from sulfuric acid to atom N2 of 4-aminopyridine resulted in the formation of a 4-aminopyridinium cation. This protonation leads to the widening of the C3–N2–C4 angle of the pyridine ring to 121.02 (15)°, compared to 115.25 (13)° in the unprotonated 4-aminopyridine (Anderson et al., 2005). Such a protonation is observed in various 4-aminopyridine acid complexes (Rotondo et al., 2009). The 4-aminopyridine ring is essentially planar with a maximum deviation from planarity of 0.002 (9) Å.

In the crystal structure, intermolecular O—H···O hydrogen bonds, established between the complex cations and sulfate anions, generate layers parallel to (001) (Fig. 2). The crystal packing of the title complex is stabilized by N—H···O hydrogen bonds between C₅H₇N₂²⁺ cations and sulfate anions and by π···π interactions between parallel pyridine rings [ring centroid-to-centroid distance: 3.754 (9) Å], which link the different species into a three dimensional network (Fig. 3).

Related literature top

For applications of metal sulfate complexes, see: Rekik et al. (2008). For clinical background to 4-aminopyridine, see: Judge & Bever (2006); Schwid et al. (1997); Strupp et al. (2004). For related compounds, see: Anderson et al. (2005); Hajlaoui et al. (2011); Quah et al. (2010); Rotondo et al. (2009).

Experimental top

4-Aminopyridine (0.19g, 2 mmol) and nickel sulfate hexahydrate (0.26g, 1 mmol) were dissolved in 15 ml of water. The resulting solution was added to an aqueous solution of sulfuric acid (0.1 M). The mixture was stirred for 20 min at room temperature. After slow evaporation during few days at ambient temperature, blue single crystals of the title compound appeared in the solution.

Structure description top

For applications of metal sulfate complexes, see: Rekik et al. (2008). For clinical background to 4-aminopyridine, see: Judge & Bever (2006); Schwid et al. (1997); Strupp et al. (2004). For related compounds, see: Anderson et al. (2005); Hajlaoui et al. (2011); Quah et al. (2010); Rotondo et al. (2009).

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures top

	Fig. 1. View of the molecular entities of the title compound with atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level. [Symmetry code: i) -x, -y, -z].
	Fig. 2. View of a corrugated layer of the title compound parallel to (001). Sulfate polyhedra are shown in yellow and cobalt polyhadra in cyan. Hydrogen bonds are denoted by dashed lines.
	Fig. 3. View of the molecular arrangement in the title structure viewed along [100]. Hydrogen bonds are denoted by dashed lines.

Bis(4-aminopyridinium) hexaaquanickel(II) bis(sulfate) top

Crystal data top

(C₅H₇N₂)₂[Ni(H₂O)₆](SO₄)₂	Z = 1
M_r = 549.18	F(000) = 286
Triclinic, P1	D_x = 1.773 Mg m⁻³
Hall symbol: -P 1	Ag Kα radiation, λ = 0.56085 Å
a = 6.212 (2) Å	Cell parameters from 25 reflections
b = 7.015 (3) Å	θ = 9–11°
c = 12.422 (2) Å	µ = 0.64 mm⁻¹
α = 100.61 (3)°	T = 293 K
β = 99.26 (2)°	Block, blue
γ = 99.57 (2)°	0.30 × 0.20 × 0.20 mm
V = 514.3 (3) Å³

Data collection top

Enraf–Nonius TurboCAD-4 diffractometer	R_int = 0.014
Radiation source: fine-focus sealed tube	θ_max = 28.0°, θ_min = 2.4°
Graphite monochromator	h = −10→10
ω scans	k = −11→11
5919 measured reflections	l = −2→20
5022 independent reflections	2 standard reflections every 120 min
3986 reflections with I > 2σ(I)	intensity decay: 5%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.097	H atoms treated by a mixture of independent and constrained refinement
S = 1.11	w = 1/[σ²(F_o²) + (0.0459P)² + 0.2397P] where P = (F_o² + 2F_c²)/3
5022 reflections	(Δ/σ)_max = 0.001
174 parameters	Δρ_max = 0.75 e Å⁻³
6 restraints	Δρ_min = −1.06 e Å⁻³

Crystal data top

(C₅H₇N₂)₂[Ni(H₂O)₆](SO₄)₂	γ = 99.57 (2)°
M_r = 549.18	V = 514.3 (3) Å³
Triclinic, P1	Z = 1
a = 6.212 (2) Å	Ag Kα radiation, λ = 0.56085 Å
b = 7.015 (3) Å	µ = 0.64 mm⁻¹
c = 12.422 (2) Å	T = 293 K
α = 100.61 (3)°	0.30 × 0.20 × 0.20 mm
β = 99.26 (2)°

Data collection top

Enraf–Nonius TurboCAD-4 diffractometer	R_int = 0.014
5919 measured reflections	2 standard reflections every 120 min
5022 independent reflections	intensity decay: 5%
3986 reflections with I > 2σ(I)

Refinement top

R[F² > 2σ(F²)] = 0.038	6 restraints
wR(F²) = 0.097	H atoms treated by a mixture of independent and constrained refinement
S = 1.11	Δρ_max = 0.75 e Å⁻³
5022 reflections	Δρ_min = −1.06 e Å⁻³
174 parameters

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.

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 > 2sigma(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 (Å²) top

	x	y	z	U_iso*/U_eq
Ni1	0.0000	0.0000	0.0000	0.01654 (6)
O1	0.15341 (17)	−0.21342 (15)	−0.07350 (9)	0.02370 (18)
O2	0.28416 (17)	0.11424 (15)	0.12233 (10)	0.0257 (2)
O3	0.10291 (17)	0.16756 (15)	−0.10704 (9)	0.02297 (18)
C1	0.9486 (2)	−0.2906 (2)	0.45752 (12)	0.0243 (2)
N2	0.9660 (3)	−0.1384 (2)	0.68016 (12)	0.0418 (4)
H1	0.9714	−0.0903	0.7496	0.050*
C3	0.7706 (3)	−0.2354 (3)	0.61472 (15)	0.0395 (4)
H3	0.6434	−0.2507	0.6454	0.047*
C5	1.1512 (3)	−0.1901 (2)	0.53005 (15)	0.0316 (3)
H5	1.2830	−0.1752	0.5032	0.038*
C4	1.1524 (3)	−0.1156 (3)	0.63905 (16)	0.0389 (4)
H4	1.2856	−0.0473	0.6861	0.047*
N1	0.9396 (3)	−0.3609 (3)	0.35006 (12)	0.0338 (3)
C2	0.7559 (3)	−0.3115 (3)	0.50454 (13)	0.0305 (3)
H2	0.6191	−0.3773	0.4601	0.037*
H103	0.056 (4)	0.261 (3)	−0.1106 (18)	0.030 (5)*
H203	0.236 (3)	0.205 (3)	−0.1029 (16)	0.023 (4)*
H7	1.061 (5)	−0.333 (4)	0.327 (2)	0.062 (8)*
H6	0.827 (5)	−0.410 (4)	0.307 (2)	0.048 (7)*
S1	0.62063 (5)	0.35433 (4)	0.81367 (3)	0.02033 (7)
O5	0.85539 (16)	0.44487 (16)	0.86606 (11)	0.0306 (2)
O7	0.53371 (17)	0.21768 (17)	0.88249 (10)	0.0295 (2)
O4	0.48753 (19)	0.50858 (17)	0.81131 (13)	0.0354 (3)
O6	0.6085 (2)	0.2407 (2)	0.70136 (11)	0.0420 (3)
H1O1	0.257 (3)	−0.228 (3)	−0.0278 (18)	0.047 (7)*
H2O1	0.065 (4)	−0.327 (3)	−0.098 (2)	0.059 (8)*
H1O2	0.363 (4)	0.225 (2)	0.129 (2)	0.047 (7)*
H2O2	0.367 (3)	0.034 (3)	0.1328 (19)	0.032 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.01578 (10)	0.01730 (10)	0.01684 (10)	0.00301 (7)	0.00362 (7)	0.00442 (7)
O1	0.0239 (4)	0.0213 (4)	0.0263 (5)	0.0059 (3)	0.0053 (4)	0.0045 (4)
O2	0.0219 (4)	0.0216 (4)	0.0301 (5)	0.0031 (3)	−0.0012 (4)	0.0038 (4)
O3	0.0195 (4)	0.0242 (4)	0.0287 (5)	0.0051 (3)	0.0078 (4)	0.0113 (4)
C1	0.0253 (6)	0.0268 (6)	0.0222 (6)	0.0068 (5)	0.0044 (5)	0.0081 (5)
N2	0.0545 (10)	0.0452 (8)	0.0222 (6)	0.0137 (7)	0.0035 (6)	−0.0014 (6)
C3	0.0401 (9)	0.0538 (10)	0.0278 (7)	0.0136 (8)	0.0131 (7)	0.0080 (7)
C5	0.0255 (6)	0.0327 (7)	0.0340 (7)	0.0020 (5)	0.0014 (6)	0.0079 (6)
C4	0.0395 (8)	0.0317 (8)	0.0358 (8)	0.0025 (6)	−0.0064 (7)	−0.0006 (6)
N1	0.0303 (6)	0.0498 (8)	0.0217 (6)	0.0093 (6)	0.0061 (5)	0.0071 (6)
C2	0.0256 (6)	0.0398 (8)	0.0253 (6)	0.0043 (6)	0.0061 (5)	0.0064 (6)
S1	0.01526 (12)	0.02018 (13)	0.02486 (15)	0.00201 (10)	0.00201 (10)	0.00623 (11)
O5	0.0164 (4)	0.0257 (5)	0.0454 (7)	−0.0001 (3)	−0.0019 (4)	0.0076 (5)
O7	0.0222 (4)	0.0331 (5)	0.0390 (6)	0.0067 (4)	0.0098 (4)	0.0184 (5)
O4	0.0231 (5)	0.0246 (5)	0.0571 (8)	0.0068 (4)	−0.0024 (5)	0.0124 (5)
O6	0.0400 (7)	0.0518 (8)	0.0275 (6)	0.0023 (6)	0.0070 (5)	−0.0019 (5)

Geometric parameters (Å, º) top

Ni1—O3ⁱ	2.0388 (11)	N2—C4	1.336 (3)
Ni1—O3	2.0388 (11)	N2—C3	1.342 (3)
Ni1—O1	2.0578 (12)	N2—H1	0.8600
Ni1—O1ⁱ	2.0578 (12)	C3—C2	1.357 (2)
Ni1—O2ⁱ	2.0701 (12)	C3—H3	0.9300
Ni1—O2	2.0701 (12)	C5—C4	1.357 (3)
O1—H1O1	0.818 (15)	C5—H5	0.9300
O1—H2O1	0.860 (15)	C4—H4	0.9300
O2—H1O2	0.828 (15)	N1—H7	0.85 (3)
O2—H2O2	0.839 (14)	N1—H6	0.79 (3)
O3—H103	0.77 (2)	C2—H2	0.9300
O3—H203	0.82 (2)	S1—O6	1.4574 (14)
C1—N1	1.324 (2)	S1—O4	1.4686 (12)
C1—C2	1.412 (2)	S1—O5	1.4793 (12)
C1—C5	1.413 (2)	S1—O7	1.4897 (12)

O3ⁱ—Ni1—O3	180.00 (5)	C2—C1—C5	117.08 (14)
O3ⁱ—Ni1—O1	92.26 (5)	C4—N2—C3	121.02 (15)
O3—Ni1—O1	87.74 (5)	C4—N2—H1	119.5
O3ⁱ—Ni1—O1ⁱ	87.74 (5)	C3—N2—H1	119.5
O3—Ni1—O1ⁱ	92.26 (5)	N2—C3—C2	121.01 (17)
O1—Ni1—O1ⁱ	180.00 (7)	N2—C3—H3	119.5
O3ⁱ—Ni1—O2ⁱ	93.96 (5)	C2—C3—H3	119.5
O3—Ni1—O2ⁱ	86.04 (5)	C4—C5—C1	119.69 (16)
O1—Ni1—O2ⁱ	89.83 (5)	C4—C5—H5	120.2
O1ⁱ—Ni1—O2ⁱ	90.17 (5)	C1—C5—H5	120.2
O3ⁱ—Ni1—O2	86.04 (5)	N2—C4—C5	121.31 (16)
O3—Ni1—O2	93.96 (5)	N2—C4—H4	119.3
O1—Ni1—O2	90.17 (5)	C5—C4—H4	119.3
O1ⁱ—Ni1—O2	89.83 (5)	C1—N1—H7	115.4 (19)
O2ⁱ—Ni1—O2	180.00 (7)	C1—N1—H6	123 (2)
Ni1—O1—H1O1	109.7 (18)	H7—N1—H6	121 (3)
Ni1—O1—H2O1	112.7 (19)	C3—C2—C1	119.88 (16)
H1O1—O1—H2O1	107.0 (19)	C3—C2—H2	120.1
Ni1—O2—H1O2	123.5 (17)	C1—C2—H2	120.1
Ni1—O2—H2O2	114.9 (14)	O6—S1—O4	111.02 (9)
H1O2—O2—H2O2	108.4 (18)	O6—S1—O5	109.76 (8)
Ni1—O3—H103	118.3 (16)	O4—S1—O5	110.07 (7)
Ni1—O3—H203	118.9 (13)	O6—S1—O7	108.89 (8)
H103—O3—H203	103.5 (18)	O4—S1—O7	109.07 (8)
N1—C1—C2	121.41 (14)	O5—S1—O7	107.96 (7)
N1—C1—C5	121.51 (14)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H1···O2ⁱⁱ	0.86	2.43	3.102 (2)	136
N2—H1···O3ⁱⁱⁱ	0.86	2.23	2.983 (2)	147
O1—H1O1···O7ⁱⁱ	0.82 (2)	2.03 (2)	2.8231 (16)	163 (2)
O1—H2O1···O5^iv	0.86 (2)	1.82 (2)	2.6741 (16)	172 (2)
O2—H1O2···O4^v	0.83 (2)	1.90 (2)	2.6952 (17)	161 (2)
O2—H2O2···O7ⁱⁱ	0.84 (2)	1.95 (2)	2.7480 (16)	159 (2)
N1—H6···O4ⁱⁱ	0.80 (3)	2.17 (3)	2.957 (2)	173 (3)
N1—H7···O5^vi	0.86 (3)	2.55 (3)	3.153 (2)	129 (2)
N1—H7···O6^vi	0.86 (3)	2.15 (3)	2.998 (2)	170 (2)
O3—H103···O5^vii	0.77 (2)	1.96 (2)	2.7072 (15)	164 (2)
O3—H203···O7^viii	0.815 (19)	1.876 (19)	2.6682 (15)	164 (2)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H1···O2ⁱ	0.86	2.43	3.102 (2)	136
N2—H1···O3ⁱⁱ	0.86	2.23	2.983 (2)	147
O1—H1O1···O7ⁱ	0.82 (2)	2.03 (2)	2.8231 (16)	163 (2)
O1—H2O1···O5ⁱⁱⁱ	0.86 (2)	1.82 (2)	2.6741 (16)	172 (2)
O2—H1O2···O4^iv	0.832 (18)	1.895 (17)	2.6952 (17)	161 (2)
O2—H2O2···O7ⁱ	0.84 (2)	1.95 (2)	2.7480 (16)	159 (2)
N1—H6···O4ⁱ	0.80 (3)	2.17 (3)	2.957 (2)	173 (3)
N1—H7···O5^v	0.86 (3)	2.55 (3)	3.153 (2)	129 (2)
N1—H7···O6^v	0.86 (3)	2.15 (3)	2.998 (2)	170 (2)
O3—H103···O5^vi	0.77 (2)	1.96 (2)	2.7072 (15)	164 (2)
O3—H203···O7^vii	0.815 (19)	1.876 (19)	2.6682 (15)	164 (2)

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

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