Sodium p-nitro­benzoxasulfamate monohydrate

The title compound, alternatively named sodium 6-nitro-3H-1,2,3-benzoxa­thia­zole 2,2-dioxide monohydrate, Na⁺·C₆H₃­N₂O₅S⁻·H₂O, consists of chains of NaO₇ units, with the seven donor-O atoms coming from two water mol­ecules and five p-­nitro­benzoxasulfamate anions. The seven-coordinate geometry around the Na⁺ ion is described as monocapped trigonal prismatic, but with a large distortion from ideal geometry. Each triangular face is defined by one O atom each from a water mol­ecule, a nitro group and a sulfonyl group. An O atom from a sulfonyl group caps one of the square faces of the trigonal prism in an unsymmetrical fashion. The water mol­ecules and one sulfonyl O atom are involved in bridging adjacent units, as is the nitro group of the anion. The sulfamate ions adopt an antiparallel alignment between the NaO₇ units and are connected to each other by C—H...O and π–π interactions. The three-dimensional crystal structure is stabilized by a network of strong O—H...N hydrogen bonds.

S1. Comment

Sulfamate derivatives have considerable commercial importance as artificial sweeteners (Spillane et al., 1996; Drew et al., 1998). The structures of acyclic sulfamate (NH₂SO₃) salts of lithium (Stade et al., 2001), rubidium (Schreuer, 1999a) and caesium (Schreuer, 1999b) were reported recently. However, no structural characterization of the compounds of cyclic sulfamates have yet appeared in the literature, and the structural investigation of the title compound is part of our continuing research on the synthesis of artificial sweeteners and their metal complexes.

A view of the title compound, alternatively named sodium 3H-6-nitro-1,2,3-benzoxathiazole 2,2-dioxidemonohydrate, is shown in Fig. 1. The Na⁺ cation has seven coordination by three O atoms of sulfamate sulfonyl groups, two O atoms of two sulfamate nitro groups and the O atoms of two water molecules. The geometry around the Na⁺ centre is best described as a distorted monocapped trigonal prism with approximate C_2v symmetry. Each triangular face is defined by one O atom each from a water molecule, a nitro group and a sulfonyl group. The dihedral angle between the two triangular faces is 2.0°. An O atom from a sulfonyl group caps one of the square faces of the trigonal prism unsymmetrically. The structure consists of chains formed by the NaO₇ units. The O atoms of the water molecules and sulfonyl groups are bicoordinating and act as bridges between Na⁺ centers. The nitro group also behaves as a bidentate donor between the cations.

The Na···Na separation is 3.6314 (6) Å. The Na—O_water, Na—O_sulfonyl and Na—O_nitro distances lie in the ranges 2.3247 (13)–2.4504 (14), 2.3843 (14)–2.8358 (15) and 2.4171 (14)–2.5985 (15) Å, respectively. All metal-oxygen distances are noticably shorter in the title compound than in its potassium analogue (Bekdemir et al., 2001). Although the K⁺ ions exhibit two different coordination polyhedra, and involve coordination by sulfamate amine N atoms, all the Na⁺ cations have the same geometry.

A packing diagram with hydrogen bonding scheme is shown in Fig. 2. The phenyl and sulfamate rings are almost planar and lie in a plane with an RMS deviation of 0.0361 Å. The sulfamate ions adopt an antiparallel aligment between the chains and are connected to each other by weak C—H···O interactions [C2···O1 3.475 (2) Å (symmetry code: x,1 + y,z)], and π-π [Cg···Cg 3.6931 (9) Å (symmetry code: -x,-y,2 - z) and Cg···Cg 3.9450 (9) Å (symmetry code:1/2 - x,1/2 - y,2 - z)] interactions. The adjacent polyhedral chains are held together by strong hydrogen bonds. The H atoms of the water molecules form O—H···N_amine hydrogen bonds [O1W···N1 2.9538 (17) Å (symmetry code: 1/2 + x,-1/2 + y,z), and 2.9844 (17) Å (symmetry code: 1/2 - x,-1/2 + y,3/2 - z)] with the amine N atom of neighboring sulfamate anions and amine nitrogen atoms accept two hydrogen bonds. The hydrogen bonds as well as the other intramolecular contacts stabilize the crystal structure in the solid state, forming a three-dimensional network.

S2. Experimental

6-Nitro-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxide (3.71 g, 10 mmol), alternatively named N-tosyl-p-nitrobenzoxa sulfamate, prepared according to the method of Andersen & Kociolek (1995) was dissolved in acetonitrile (200 ml). NaN₃ (0.65 g, 10 mmol) was dissolved in water (ca 2 ml) and added dropwise into the first solution. The mixture was stirred by means of a magnetic stirrer at room temperature for one hour. The solvent was removed under reduced pressure and the title compound was collected as a yellow solid. The solid was washed with chloroform and recrystallized from THF/water (1/1) to obtain suitable crystals for X-ray analysis.

S3. Refinement

Water H atoms were found in difference maps and were positionally refined with geometric restraints (O—H 0.82, H···H 1.30 Å) and with U_iso(H) = 1.5 U_eq(C) (Sheldrick, 1997). Other H atoms were placed in calculated positions 0.93 Å from their parent atoms with U_iso(H) = 1.2 U_eq(C).

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick,1997).

Figures

	Fig. 1. View of the title compound showing the coordination around the sodium ions. Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes: (i) 1/2 - x,1/2 + y,3/2 - z; (ii) 1/2 + x,1/2 + y,z; (iii) 1/2 - x,1/2 - y,2 - z; (iv) x,-y,-1/2 + z.
	Fig. 2. A part of packing diagram of the title compound showing the hydrogen bonding. Symmetry codes: (i) 1/2 - x,1/2 + y,3/2 - z; (ii) 1/2 + x,1/2 + y,z; (iii) 1/2 - x,1/2 - y,2 - z; (iv) x,-y,-1/2 + z.

Sodium p-nitrobenzoxasulfamate monohydrate

Crystal data

Na^+·C6H3N2O5S^−·H2O	F(000) = 1040
Mr = 256.17	Dx = 1.871 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71069 Å
a = 13.0610 (7) Å	Cell parameters from 3359 reflections
b = 6.8155 (4) Å	θ = 3.2–27.5°
c = 20.7293 (11) Å	µ = 0.42 mm^−1
β = 99.677 (1)°	T = 298 K
V = 1819.01 (17) Å^3	Column, yellow
Z = 8	0.55 × 0.16 × 0.11 mm

Data collection

Bruker SMART1000 CCD area detector diffractometer	2096 independent reflections
Radiation source: fine-focus sealed tube	1758 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω scans	θmax = 27.5°, θmin = 2.0°
Absorption correction: multi-scan SADABS (Bruker, 1999)	h = −16→15
Tmin = 0.761, Tmax = 0.949	k = −8→7
6528 measured reflections	l = −26→26

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)] = 0.030	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.085	w = 1/[σ^2(Fo^2) + (0.05P)^2 + 0.652P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
2096 reflections	Δρmax = 0.26 e Å^−3
151 parameters	Δρmin = −0.37 e Å^−3
3 restraints

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
S1	0.92560 (3)	0.19080 (6)	0.15613 (2)	0.02760 (13)
Na1	0.70264 (6)	−0.03018 (10)	0.23785 (3)	0.0414 (2)
O1W	0.63443 (9)	0.28414 (18)	0.24050 (6)	0.0342 (3)
H1W1	0.5972 (14)	0.342 (3)	0.2114 (7)	0.051*
H2W1	0.6116 (16)	0.310 (3)	0.2741 (6)	0.051*
O1	1.00939 (10)	0.32593 (19)	0.17193 (6)	0.0422 (3)
O2	0.84291 (10)	0.21684 (19)	0.19272 (6)	0.0392 (3)
O3	0.87654 (10)	0.22657 (17)	0.07865 (5)	0.0352 (3)
O4	0.80116 (11)	−0.3934 (2)	−0.12360 (6)	0.0473 (3)
O5	0.78181 (12)	−0.0843 (2)	−0.14476 (6)	0.0538 (4)
N1	0.95956 (10)	−0.0322 (2)	0.15242 (6)	0.0296 (3)
N2	0.80933 (11)	−0.2208 (2)	−0.10668 (7)	0.0363 (3)
C1	0.92845 (11)	−0.0968 (2)	0.08939 (7)	0.0250 (3)
C2	0.93669 (13)	−0.2855 (2)	0.06555 (8)	0.0305 (3)
H2	0.9683	−0.3844	0.0928	0.037*
C3	0.89724 (12)	−0.3238 (2)	0.00093 (8)	0.0321 (4)
H3	0.9007	−0.4502	−0.0155	0.039*
C4	0.85239 (11)	−0.1745 (2)	−0.03979 (7)	0.0285 (3)
C5	0.84363 (12)	0.0177 (2)	−0.01812 (8)	0.0292 (3)
H5	0.8140	0.1174	−0.0458	0.035*
C6	0.88135 (11)	0.0492 (2)	0.04626 (7)	0.0256 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0309 (2)	0.0266 (2)	0.0252 (2)	0.00165 (14)	0.00442 (14)	0.00046 (14)
Na1	0.0607 (5)	0.0303 (4)	0.0351 (4)	0.0110 (3)	0.0134 (3)	0.0036 (3)
O1W	0.0378 (6)	0.0358 (7)	0.0285 (6)	0.0107 (5)	0.0043 (5)	0.0011 (5)
O1	0.0434 (7)	0.0390 (7)	0.0429 (7)	−0.0107 (5)	0.0035 (6)	0.0000 (6)
O2	0.0408 (7)	0.0391 (7)	0.0403 (7)	0.0035 (5)	0.0145 (5)	−0.0063 (5)
O3	0.0498 (7)	0.0265 (6)	0.0268 (6)	0.0116 (5)	−0.0011 (5)	0.0016 (5)
O4	0.0503 (8)	0.0527 (9)	0.0404 (7)	−0.0163 (7)	0.0115 (6)	−0.0160 (6)
O5	0.0641 (9)	0.0653 (10)	0.0276 (6)	0.0019 (8)	−0.0052 (6)	0.0035 (6)
N1	0.0360 (7)	0.0281 (7)	0.0239 (6)	0.0069 (6)	0.0031 (5)	0.0035 (5)
N2	0.0306 (7)	0.0504 (9)	0.0290 (7)	−0.0083 (6)	0.0080 (6)	−0.0063 (6)
C1	0.0227 (7)	0.0277 (8)	0.0252 (7)	0.0025 (6)	0.0058 (5)	0.0038 (6)
C2	0.0344 (8)	0.0251 (8)	0.0324 (8)	0.0059 (6)	0.0068 (6)	0.0053 (6)
C3	0.0332 (8)	0.0275 (8)	0.0371 (9)	0.0007 (6)	0.0100 (7)	−0.0037 (6)
C4	0.0250 (7)	0.0370 (9)	0.0240 (7)	−0.0026 (6)	0.0059 (6)	−0.0017 (6)
C5	0.0274 (7)	0.0329 (8)	0.0268 (8)	0.0034 (6)	0.0029 (6)	0.0060 (6)
C6	0.0267 (7)	0.0237 (7)	0.0270 (7)	0.0029 (6)	0.0058 (6)	0.0016 (6)

Geometric parameters (Å, º)

S1—O1	1.4257 (13)	O3—C6	1.3893 (18)
S1—O2	1.4312 (12)	N1—C1	1.374 (2)
S1—O3	1.6442 (11)	O4—N2	1.227 (2)
S1—N1	1.5889 (13)	O5—N2	1.234 (2)
Na1—O1W	2.3244 (14)	N2—C4	1.441 (2)
Na1—O1W^i	2.4516 (15)	C1—C6	1.408 (2)
Na1—O1^ii	2.8355 (15)	C1—C2	1.388 (2)
Na1—O2^i	2.3846 (14)	C2—C3	1.377 (2)
Na1—O2	2.7644 (15)	C2—H2	0.9300
Na1—O4^iii	2.4173 (14)	C3—C4	1.387 (2)
Na1—O5^iv	2.5988 (15)	C3—H3	0.9300
Na1—Na1^v	3.6314 (6)	C4—C5	1.396 (2)
O1W—H1W1	0.811 (9)	C5—C6	1.360 (2)
O1W—H2W1	0.821 (9)	C5—H5	0.9300
O1—S1—O2	114.62 (8)	Na1^v—O1W—H2W1	99.4 (16)
O1—S1—N1	114.79 (8)	H1W1—O1W—H2W1	105.8 (17)
O2—S1—N1	112.70 (8)	S1—O1—Na1^vi	157.05 (8)
O1—S1—O3	106.66 (7)	S1—O2—Na1^v	134.15 (8)
O2—S1—O3	107.12 (7)	S1—O2—Na1	134.90 (7)
N1—S1—O3	99.25 (6)	Na1^v—O2—Na1	89.39 (4)
O1W—Na1—O2^i	121.10 (5)	C6—O3—S1	107.53 (9)
O1W—Na1—O4^iii	106.08 (5)	N2—O4—Na1^iii	118.24 (11)
O2^i—Na1—O4^iii	117.99 (6)	N2—O5—Na1^vii	148.51 (12)
O1W—Na1—O1W^i	142.73 (5)	C1—N1—S1	108.19 (10)
O2^i—Na1—O1W^i	79.24 (5)	O4—N2—O5	122.54 (15)
O4^iii—Na1—O1W^i	86.70 (5)	O4—N2—C4	119.10 (15)
O1W—Na1—O5^iv	78.16 (5)	O5—N2—C4	118.36 (15)
O2^i—Na1—O5^iv	75.66 (5)	N1—C1—C2	127.39 (14)
O4^iii—Na1—O5^iv	157.15 (6)	N1—C1—C6	113.89 (14)
O1W^i—Na1—O5^iv	77.71 (5)	C2—C1—C6	118.71 (14)
O1W—Na1—O2	74.05 (5)	C3—C2—C1	118.89 (14)
O2^i—Na1—O2	153.05 (4)	C3—C2—H2	120.6
O4^iii—Na1—O2	72.87 (5)	C1—C2—H2	120.6
O1W^i—Na1—O2	76.82 (4)	C2—C3—C4	120.24 (15)
O5^iv—Na1—O2	87.25 (5)	C2—C3—H3	119.9
O1W—Na1—O1^ii	90.94 (5)	C4—C3—H3	119.9
O2^i—Na1—O1^ii	75.44 (5)	C3—C4—C5	122.79 (15)
O4^iii—Na1—O1^ii	65.37 (5)	C3—C4—N2	118.77 (15)
O1W^i—Na1—O1^ii	125.78 (5)	C5—C4—N2	118.39 (14)
O5^iv—Na1—O1^ii	137.47 (5)	C6—C5—C4	115.35 (14)
O2—Na1—O1^ii	129.38 (5)	C6—C5—H5	122.3
Na1—O1W—Na1^v	98.96 (4)	C4—C5—H5	122.3
Na1—O1W—H1W1	127.9 (15)	C5—C6—O3	124.97 (13)
Na1^v—O1W—H1W1	106.2 (16)	C5—C6—C1	124.00 (15)
Na1—O1W—H2W1	114.2 (14)	O3—C6—C1	111.01 (13)
O1—S1—O3—C6	122.54 (11)	O5—N2—C4—C3	−170.80 (15)
O2—S1—O3—C6	−114.28 (11)	O4—N2—C4—C5	−168.26 (14)
N1—S1—O3—C6	3.06 (11)	O5—N2—C4—C5	11.6 (2)
O1—S1—N1—C1	−116.69 (11)	C3—C4—C5—C6	−0.6 (2)
O2—S1—N1—C1	109.63 (11)	N2—C4—C5—C6	176.92 (13)
O3—S1—N1—C1	−3.42 (12)	C4—C5—C6—O3	−177.07 (14)
S1—N1—C1—C2	−175.71 (13)	C4—C5—C6—C1	1.3 (2)
S1—N1—C1—C6	2.82 (16)	S1—O3—C6—C5	176.79 (13)
N1—C1—C2—C3	177.54 (15)	S1—O3—C6—C1	−1.73 (15)
C6—C1—C2—C3	−0.9 (2)	N1—C1—C6—C5	−179.21 (14)
C1—C2—C3—C4	1.6 (2)	C2—C1—C6—C5	−0.5 (2)
C2—C3—C4—C5	−0.8 (2)	N1—C1—C6—O3	−0.66 (19)
C2—C3—C4—N2	−178.32 (14)	C2—C1—C6—O3	178.01 (13)
O4—N2—C4—C3	9.4 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W1···N1^viii	0.81 (1)	2.17 (1)	2.9521 (17)	161 (2)
O1W—H2W1···N1^v	0.82 (1)	2.20 (1)	2.9859 (17)	161 (2)
C2—H2···O1^ix	0.93	2.57	3.475 (2)	166

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