Bis(acesulfamato-κO⁴)diaqua­bis­(3-methyl­pyridine-κN)nickel(II)

In the crystal structure of the title compound [systematic name: diaqua­bis(6-methyl-2,2-dioxo-1,2,3-oxathia­zin-4-olato-κO⁴)bis­(3-methyl­pyridine-κN)nickel(II)], [Ni(C₄H₄NO₄S)₂(C₆H₇N)₂(H₂O)₂], the Ni^II centre resides on a centre of symmetry and has a distorted octa­hedral geometry. The basal plane is formed by two carbonyl O atoms of two monodentate trans-oriented acesulfamate ligands and two trans aqua ligands. The axial positions in the octa­hedron are occupied by two N atoms of two trans pyridine ligands. Mol­ecules are stacked in columns running along the a axis. There are π–π stacking inter­actions between the mol­ecules in each column, with a distance of 3.623 (2) Å between the centroids of the pyridine rings. There are also O—H...O inter­actions between the columns.

S1. Comment

Acesulfame (C₄H₅SO₄N) is an oxathiazinone dioxide and is systematically named as 6-methyl-1,2,3-oxathiazin-4(3H)-one 2,2-dioxide; it is also known as 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide or acetosulfam. It was discovered by the chemist Karl Clauss in 1967 (Clauss & Jensen, 1973) and has been widely used as a non-calorific artificial sweetener since 1988, after the US Food and Drug Administration granted approval (Duffy & Anderson, 1998). Many countries have approved the use of acesulfame K, viz. the potassium salt of acesulfame, in soft drinks, candies, toothpastes, mouthwashes, cosmetics and pharmacological preparations (Mukherjee & Chakrabarti, 1997).

The acesulfamate anion (acs⁻), C₄H₄NO₄S⁻, has several potential donor atoms and thus, as a polyfunctional ligand, it can engage in N, O_CO, O_OSO or O coordination with different metal ions, similar to the saccharinate anion (sac). The chemistry of the common artificial sweetener acesulfame (acs) is an interesting area of research not only because of its biological significance but also because of its coordination properties. Despite its potential for diversity in coordination, little has been reported on the coordination behaviour of acesulfamate as a ligand. Recently, we have started to study the synthesis and the spectroscopic and structural properties of acesulfamate metal complexes (İçbudak, Heren et al., 2005; İçbudak, Bulut et al., 2005; Bulut et al., 2005; İçbudak et al., 2006; Dege et al., 2006). The donor sites of the acesulfamate ligand are similar to those of the saccharinate anion (see scheme), and therefore the coordination behaviour of the title compound, (I), can be compared with the coordination chemistry of saccharin, since all possible bonding patterns of saccharin are well documented by X-ray diffraction studies (İçbudak et al., 2002, and references therein). In order to examine the coordination behaviour of acesulfame in transition metal complexes, complex (I) has been synthesized and its crystal structure is presented here.

A view of the molecule of (I), together with the atom-numbering scheme and the intramolecular hydrogen bonding, are shown in Fig. 1. Selected geometric parameters are listed in Table 1. The structure is composed of discrete [Ni(acs)₂(mepyr)₂(H₂O)₂] molecules (mepyr is methylpyridine). The local structure around the Ni^II ion, which resides on a centre of symmetry, is that of an octahedron, of which the equatorial plane [O4/O5/O4ⁱ/O5ⁱ; symmetry code: (i) −x + 1, −y, −z] is formed by two carbonyl O atoms of two trans-oriented acesulfamate ligands (O4 and O4ⁱ) and two trans aqua ligands (O5 and O5ⁱ). The axial positions in the octahedron are occupied by two N atoms of two trans pyridine ligands (N2 and N2ⁱ). The bond lengths and angles of the acesulfamate ligands are similar to the corresponding values of the copper(II)–acesulfamate complex [Cu(acs)₂(mepyr)₂] (Dege et al., 2006), while there are some differences from the analogous potassium salt (Paulus, 1975). The most pronounced of these are the S1—N1 bond length and O2═S1═O3 bond angle, which are increased to 1.571 (2) Å and 116.45 (15)°, respectively, in (I), from the corresponding values of 1.544 (2) Å and 113.7 (2)°, respectively, in the potassium salt. The acesulfame ring adopts a half-chair conformation, as is evident from the puckering parameters [Q = 0.305 (2) Å, θ = 60.5 (4)° and ϕ = 11.2 (5)° for the atom sequence S1—O1—C3═C2—C1═N1 (Cremer & Pople, 1975)]. The 3-methylpyridine ligands are planar. Their individual bond lengths do not depart significantly from their respective mean values and correspond well to those reported for this ligand in other complexes (Rotondo, 2006; Goto et al., 2000; Nakagawa et al., 2000).

The most relevant aspect of this structure is the carbonyl oxygen coordination of the acesulfamate anions, since the acesulfamate ligand coordinates to the metal(II) ion through the ring N atom in [Co(acs)₂(H₂O)₄] (İçbudak, Bulut et al., 2005) and is bidentate coordinated to the metal(II) ion in [Cu(ampym)₂(acs)₂] (ampym is aminopyrimidine; Bulut et al., 2005) and [Cu(acs)₂(mepyr)₂] (Dege et al., 2006). Apart from considering the structural resemblance of acesulfame to saccharine, it can also be said that this coordination behavior is very interesting since saccharine usually interacts with metal atoms through its deprotonated N-atom (Haider et al., 1985). This unusual carbonyl coordination of saccharine was observed in a few cases either in mixed ligand complexes of saccharine [Ni(sac)₂(py)₄].2py (py is pyridine; İçbudak et al., 2002) or in trivalent lanthanide– and ytrium–saccharinate complexes (Piro et al., 2002). In the former case, the carbonyl oxygen coordination was attributed to the steric effect, while in the latter case the heavy metal ion affects the coordination mode. Nevertheless, none of these reasons can be adopted for carbonyl oxygen coordination of the acesulfamate ligand to nickel(II) ion.

When the local structure around the Ni^II ion in (I) is compared with that in [Ni(acs)₂(H₂O)₄] (İçbudak et al., 2006), one can observe that the Ni—O_acs distance of 2.0747 (15) Å in (I) is almost equal to that in [Ni(acs)₂(H₂O)₄] [2.0689 (11) Å], while the Ni—O_aqua distance of 2.0917 (16) Å in (I) is longer than the two Ni—O_aqua distances of 2.0481 (13) and 2.0568 (11) Å in [Ni(acs)₂(H₂O)₄]. The angular distortions of the octahedral environment of the Ni^II ion in (I) also show some differences from those in the [Ni(acs)₂(H₂O)₄] complex. The maximum deviation from an ideal O—M—O angle of 90° is 3.87 (7)° for (I), while it is 5.09 (5)° for the [Ni(acs)₂(H₂O)₄] complex. With regard to the ligand geometry, the C—O bond length of the carbonyl group is increased by 0.017 Å in (I) compared with that in the potassium salt, whereas no significant changes are observed for the sulfonyl group. The bond lengths of these groups are especially important for IR studies, from which the coordination behaviour of the ligand (Grupce et al., 2001; Naumov et al., 2001) can be estimated.

On the basis of the estimated 'effective' ionic radii for Cu²⁺ (0.73 Å) and Ni²⁺ (0.69 Å) in a six-coordinate environment (Shannon, 1976), the corresponding M—N_mepyr bond distance in (I) and [Cu(acs)₂(mepyr)₂] (Dege et al., 2006) would be expected to be fairly similar in magnitude. This premise is clearly not supported by a comparison of the M—N_mepyr bond distances in the two complexes. In terms of the M—N_mepyr distance, the Ni—N distances in (I) are ca 0.09 Å longer than their respective Cu—N bond distances in [Cu(acs)₂(mepyr)₂].

In the molecular structure, an intramolecular O5—H5A···N1 contact leads to the formation of a six-membered ring, which is fused with the acesulfame ring. In the crystal structure (Fig. 2), molecules of the title compound are packed in columns running along the a axis. The molecules in each column are linked to one another in a zigzag arrangement via π–π stacking interactions, which takes the form of stacks of pyridine rings. The pyridine rings at (x, y, z) and (−x, −y, −z) present an interplanar spacing of 3.308 (2) Å and a centroid separation of 3.623 (2) Å, corresponding to a ring offset of 1.476 (3) Å. In addition, there are O—H···O intermolecular interactions between the molecules in the 2₁ screw symmetry-related columns. In this interaction, atom O5 acts as a hydrogen-bond donor, via atom H5B, to atom O2 at (−x + 1, y + 1/2, −z − 1/2). The detailed geometry of the intermolecular interactions is given in Table 2. There are no other significant intermolecular interactions, such as C—H···π interactions, in the crystal structure of (I).

S2. Experimental

[Ni(acs)₂(H₂O)₄] (0,91 g, 2 mmol) was dissolved in 50 ml of methanol and a solution of 3-methylpyridine (0,37 g, 4 mmol) in 30 ml of methanol was added with stirring. The solution was stirred vigorously for 3 h at 323 K and then cooled to ambient temperature. The resulting blue crystals were washed with acetone and dried under vacuum (yield 90%).

S3. Refinement

The coordinates of the H atoms of the water molecule were determined from a difference map and were then allowed to refine isotropically [O—H = 0.83 (4) Å]. All other H atoms were positioned geometrically and refined with a riding model, fixing the bond lengths at 0.93 and 0.96 Å for CH and CH₃, respectively. The displacement parameters of the H atoms were constrained as U_iso(H) = 1.2U_eq(parent), or 1.5U_eq(C) for methyl H atoms. Riding methyl H atoms were allowed to rotate freely during refinement using the AFIX 137 command of SHELXL97 (Sheldrick, 1997).

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2003).

Figures

	Fig. 1. : A view of the title molecule, showing the atom-labelling scheme and 40% probability displacement ellipsoids. The intramolecular O—H···N hydrogen bonds are represented as broken lines. [Symmetry code: (i) −x + 1, −y, −z.]
	Fig. 2. : A packing diagram of (I), showing the O—H···O and π–π interactions. For clarity, only H atoms involved in hydrogen bonding have been included.

diaquabis[6-methyl-2,2-dioxo-1,2,3-oxathiazin-4-olato-κO⁴]bis(3- methylpyridine-κN)nickel(II)}

Crystal data

[Ni(C4H4NO4S)2(C6H7N)2(H2O)2]	F(000) = 628
Mr = 605.28	Dx = 1.580 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 20424 reflections
a = 8.9738 (6) Å	θ = 2.3–27.9°
b = 12.8267 (7) Å	µ = 0.99 mm^−1
c = 11.1870 (8) Å	T = 296 K
β = 98.875 (5)°	Prism, blue
V = 1272.25 (14) Å^3	0.46 × 0.28 × 0.09 mm
Z = 2

Data collection

Stoe IPDS-2 diffractometer	2999 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	2271 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.063
Detector resolution: 6.67 pixels mm^-1	θmax = 27.8°, θmin = 2.3°
ω scans	h = −11→11
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)	k = −16→16
Tmin = 0.484, Tmax = 0.881	l = −14→14
21143 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.085	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0472P)^2 + 0.0532P] where P = (Fo^2 + 2Fc^2)/3
2999 reflections	(Δ/σ)max = 0.001
179 parameters	Δρmax = 0.53 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

Special details

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.

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 > σ(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 (Ų)

	x	y	z	Uiso*/Ueq
Ni1	0.5000	0.0000	0.0000	0.03120 (11)
S1	0.24047 (7)	−0.10679 (4)	−0.40631 (5)	0.04145 (15)
O1	0.2896 (3)	−0.03139 (13)	−0.50889 (16)	0.0569 (5)
O2	0.2985 (3)	−0.20504 (14)	−0.43348 (19)	0.0741 (7)
O3	0.0822 (2)	−0.09927 (19)	−0.41537 (19)	0.0706 (6)
O4	0.41014 (19)	0.07055 (11)	−0.16205 (14)	0.0396 (4)
O5	0.5566 (2)	0.15061 (12)	0.06289 (17)	0.0412 (4)
H5A	0.604 (4)	0.143 (3)	0.132 (3)	0.073 (11)*
H5B	0.607 (4)	0.192 (3)	0.028 (3)	0.072 (10)*
N1	0.3243 (2)	−0.06581 (14)	−0.28152 (17)	0.0432 (5)
N2	0.2977 (2)	0.01963 (13)	0.06929 (17)	0.0375 (4)
C1	0.3608 (2)	0.03544 (17)	−0.26538 (19)	0.0347 (4)
C2	0.3491 (3)	0.10524 (17)	−0.3692 (2)	0.0411 (5)
H2	0.3644	0.1762	−0.3554	0.049*
C3	0.3177 (3)	0.07229 (17)	−0.4821 (2)	0.0384 (5)
C4	0.3141 (3)	0.1338 (2)	−0.5950 (2)	0.0523 (6)
H4A	0.3623	0.0949	−0.6517	0.078*
H4B	0.3664	0.1985	−0.5769	0.078*
H4C	0.2113	0.1477	−0.6295	0.078*
C5	0.2164 (3)	0.10654 (18)	0.0438 (2)	0.0449 (5)
H5	0.2527	0.1574	−0.0035	0.054*
C6	0.0812 (3)	0.1240 (2)	0.0848 (3)	0.0527 (6)
H6	0.0286	0.1859	0.0670	0.063*
C7	0.0259 (3)	0.0480 (2)	0.1522 (2)	0.0531 (6)
H7	−0.0658	0.0579	0.1795	0.064*
C8	0.1059 (3)	−0.0430 (2)	0.1799 (2)	0.0471 (6)
C9	0.2428 (3)	−0.05283 (18)	0.1370 (2)	0.0412 (5)
H9	0.2993	−0.1130	0.1564	0.049*
C10	0.0490 (4)	−0.1294 (3)	0.2517 (3)	0.0668 (8)
H10A	0.1301	−0.1765	0.2793	0.100*
H10B	−0.0302	−0.1663	0.2016	0.100*
H10C	0.0108	−0.1004	0.3201	0.100*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0339 (2)	0.03056 (18)	0.03024 (19)	−0.00187 (15)	0.00831 (14)	−0.00078 (15)
S1	0.0567 (4)	0.0338 (3)	0.0356 (3)	−0.0025 (2)	0.0128 (3)	−0.0041 (2)
O1	0.0940 (15)	0.0433 (9)	0.0354 (9)	−0.0105 (9)	0.0167 (9)	−0.0036 (7)
O2	0.125 (2)	0.0415 (10)	0.0593 (13)	0.0171 (11)	0.0245 (13)	−0.0092 (9)
O3	0.0538 (12)	0.1060 (17)	0.0528 (12)	−0.0145 (11)	0.0104 (9)	−0.0096 (11)
O4	0.0483 (10)	0.0384 (8)	0.0315 (8)	0.0002 (7)	0.0043 (7)	−0.0018 (6)
O5	0.0509 (10)	0.0346 (8)	0.0381 (9)	−0.0057 (7)	0.0069 (8)	0.0007 (7)
N1	0.0583 (13)	0.0362 (9)	0.0353 (10)	−0.0048 (8)	0.0077 (9)	0.0007 (8)
N2	0.0395 (10)	0.0359 (10)	0.0387 (10)	−0.0030 (7)	0.0110 (8)	−0.0030 (7)
C1	0.0335 (11)	0.0372 (10)	0.0348 (11)	0.0053 (8)	0.0092 (9)	0.0006 (8)
C2	0.0551 (15)	0.0336 (10)	0.0343 (12)	−0.0006 (10)	0.0053 (10)	0.0016 (9)
C3	0.0439 (13)	0.0351 (10)	0.0375 (12)	−0.0007 (9)	0.0109 (10)	0.0000 (9)
C4	0.0728 (18)	0.0478 (13)	0.0370 (13)	−0.0058 (12)	0.0110 (12)	0.0035 (10)
C5	0.0459 (14)	0.0424 (12)	0.0474 (14)	0.0023 (10)	0.0102 (11)	−0.0023 (10)
C6	0.0494 (15)	0.0554 (15)	0.0538 (16)	0.0113 (11)	0.0096 (12)	−0.0120 (12)
C7	0.0408 (14)	0.0752 (17)	0.0457 (14)	0.0029 (12)	0.0142 (11)	−0.0167 (13)
C8	0.0466 (15)	0.0623 (14)	0.0348 (12)	−0.0152 (12)	0.0139 (10)	−0.0098 (11)
C9	0.0437 (13)	0.0424 (12)	0.0391 (12)	−0.0060 (10)	0.0121 (10)	−0.0035 (9)
C10	0.067 (2)	0.085 (2)	0.0538 (17)	−0.0234 (16)	0.0268 (15)	0.0002 (14)

Geometric parameters (Å, º)

Ni1—O4	2.0747 (15)	C2—C3	1.320 (3)
Ni1—O4^i	2.0747 (15)	C2—H2	0.9300
Ni1—O5^i	2.0917 (16)	C3—C4	1.486 (3)
Ni1—O5	2.0917 (16)	C4—H4A	0.9600
Ni1—N2	2.0964 (18)	C4—H4B	0.9600
Ni1—N2^i	2.0964 (18)	C4—H4C	0.9600
S1—O3	1.412 (2)	C5—C6	1.380 (4)
S1—O2	1.4145 (19)	C5—H5	0.9300
S1—N1	1.571 (2)	C6—C7	1.371 (4)
S1—O1	1.6134 (18)	C6—H6	0.9300
O1—C3	1.378 (3)	C7—C8	1.380 (4)
O4—C1	1.256 (3)	C7—H7	0.9300
O5—H5A	0.83 (4)	C8—C9	1.392 (3)
O5—H5B	0.83 (4)	C8—C10	1.503 (4)
N1—C1	1.345 (3)	C9—H9	0.9300
N2—C5	1.338 (3)	C10—H10A	0.9600
N2—C9	1.340 (3)	C10—H10B	0.9600
C1—C2	1.458 (3)	C10—H10C	0.9600
O4—Ni1—O4^i	180.00 (9)	C3—C2—C1	123.0 (2)
O4—Ni1—O5^i	93.87 (7)	C3—C2—H2	118.5
O4^i—Ni1—O5^i	86.13 (7)	C1—C2—H2	118.5
O4—Ni1—O5	86.13 (7)	C2—C3—O1	121.5 (2)
O4^i—Ni1—O5	93.87 (7)	C2—C3—C4	128.1 (2)
O5^i—Ni1—O5	180.00 (13)	O1—C3—C4	110.35 (19)
O4—Ni1—N2	91.64 (7)	C3—C4—H4A	109.5
O4^i—Ni1—N2	88.36 (7)	C3—C4—H4B	109.5
O5^i—Ni1—N2	93.21 (7)	H4A—C4—H4B	109.5
O5—Ni1—N2	86.79 (7)	C3—C4—H4C	109.5
O4—Ni1—N2^i	88.36 (7)	H4A—C4—H4C	109.5
O4^i—Ni1—N2^i	91.64 (7)	H4B—C4—H4C	109.5
O5^i—Ni1—N2^i	86.79 (7)	N2—C5—C6	122.9 (2)
O5—Ni1—N2^i	93.21 (7)	N2—C5—H5	118.6
N2—Ni1—N2^i	180.0	C6—C5—H5	118.6
O3—S1—O2	116.45 (15)	C7—C6—C5	118.6 (2)
O3—S1—N1	112.31 (12)	C7—C6—H6	120.7
O2—S1—N1	110.31 (13)	C5—C6—H6	120.7
O3—S1—O1	106.89 (13)	C6—C7—C8	120.3 (2)
O2—S1—O1	103.35 (12)	C6—C7—H7	119.8
N1—S1—O1	106.59 (10)	C8—C7—H7	119.8
C3—O1—S1	118.97 (14)	C7—C8—C9	117.1 (2)
C1—O4—Ni1	133.01 (14)	C7—C8—C10	122.4 (2)
Ni1—O5—H5A	105 (2)	C9—C8—C10	120.5 (3)
Ni1—O5—H5B	124 (2)	N2—C9—C8	123.6 (2)
H5A—O5—H5B	106 (3)	N2—C9—H9	118.2
C1—N1—S1	121.05 (16)	C8—C9—H9	118.2
C5—N2—C9	117.5 (2)	C8—C10—H10A	109.5
C5—N2—Ni1	119.73 (15)	C8—C10—H10B	109.5
C9—N2—Ni1	122.72 (15)	H10A—C10—H10B	109.5
O4—C1—N1	120.92 (19)	C8—C10—H10C	109.5
O4—C1—C2	119.0 (2)	H10A—C10—H10C	109.5
N1—C1—C2	120.0 (2)	H10B—C10—H10C	109.5
O3—S1—O1—C3	87.0 (2)	Ni1—O4—C1—C2	−160.83 (16)
O2—S1—O1—C3	−149.5 (2)	S1—N1—C1—O4	170.81 (17)
N1—S1—O1—C3	−33.3 (2)	S1—N1—C1—C2	−11.6 (3)
O5^i—Ni1—O4—C1	−9.4 (2)	O4—C1—C2—C3	170.8 (2)
O5—Ni1—O4—C1	170.6 (2)	N1—C1—C2—C3	−6.8 (4)
N2—Ni1—O4—C1	−102.8 (2)	C1—C2—C3—O1	1.8 (4)
N2^i—Ni1—O4—C1	77.2 (2)	C1—C2—C3—C4	−174.9 (2)
O3—S1—N1—C1	−87.8 (2)	S1—O1—C3—C2	20.3 (3)
O2—S1—N1—C1	140.5 (2)	S1—O1—C3—C4	−162.50 (19)
O1—S1—N1—C1	29.0 (2)	C9—N2—C5—C6	0.4 (4)
O4—Ni1—N2—C5	−37.47 (18)	Ni1—N2—C5—C6	179.0 (2)
O4^i—Ni1—N2—C5	142.53 (18)	N2—C5—C6—C7	−1.5 (4)
O5^i—Ni1—N2—C5	−131.44 (18)	C5—C6—C7—C8	1.1 (4)
O5—Ni1—N2—C5	48.56 (18)	C6—C7—C8—C9	0.3 (4)
O4—Ni1—N2—C9	141.04 (18)	C6—C7—C8—C10	−178.9 (3)
O4^i—Ni1—N2—C9	−38.96 (18)	C5—N2—C9—C8	1.1 (3)
O5^i—Ni1—N2—C9	47.07 (19)	Ni1—N2—C9—C8	−177.42 (17)
O5—Ni1—N2—C9	−132.93 (19)	C7—C8—C9—N2	−1.5 (4)
Ni1—O4—C1—N1	16.7 (3)	C10—C8—C9—N2	177.8 (2)

Symmetry code: (i) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5A···N1^i	0.83 (4)	1.96 (4)	2.739 (3)	155 (3)
O5—H5B···O2^ii	0.83 (4)	1.96 (4)	2.792 (3)	173 (4)

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