The three-dimensional hydrogen-bonded structures in the ammonium and sodium salt hydrates of 4-amino­phenyl­arsonic acid

The structures of two hydrated salts of 4-amino­phenyl­arsonic acid (p-arsanilic acid), namely ammonium 4-amino­phenyl­arsonate monohydrate, NH₄⁺·C₆H₇AsNO₃⁻·H₂O, (I), and the one-dimensional coordination polymer catena-poly[[(4-amino­phenyl­arsonato-κO)di­aqua­sodium]-μ-aqua], [Na(C₆H₇AsNO₃)(H₂O)₃]_n, (II), have been determined. In the structure of the ammonium salt, (I), the ammonium cations, arsonate anions and water mol­ecules inter­act through inter-species N—H...O and arsonate and water O—H...O hydrogen bonds, giving the common two-dimensional layers lying parallel to (010). These layers are extended into three dimensions through bridging hydrogen-bonding inter­actions involving the para-amine group acting both as a donor and an acceptor. In the structure of the sodium salt, (II), the Na⁺ cation is coordinated by five O-atom donors, one from a single monodentate arsonate ligand, two from monodentate water mol­ecules and two from bridging water mol­ecules, giving a very distorted square-pyramidal coordination environment. The water bridges generate one-dimensional chains extending along c and extensive interchain O—H...O and N—H...O hydrogen-bonding inter­actions link these chains, giving an overall three-dimensional structure. The two structures reported here are the first reported examples of salts of p-arsanilic acid.

S1. Introduction

4-Amino­phenyl­arsonic acid (p-arsanilic acid) has a long history as an anti­helminth in veterinary applications (Thomas, 1905; Steverding, 2010) and more commonly as a previously employed anti­syphilitic drug (Ehrlich & Bertheim, 1907; Burke, 1925), when used as the hydrated sodium salt, under a variety of common names, primarily atoxyl (Jolliffe, 1993; O'Neil, 2001; Bosch & Rosich, 2008). The crystal structure of the parent acid (Shimada, 1961; Nuttall & Hunter, 1996) has confirmed the presence of a Ph–NH₃⁺–AsO₃H^- zwitterion in the solid state. These structures are among only a small number of examples in the crystallographic literature involving this acid in any form, including the complexes with silver, zinc, cadmium and lead (Lesikar-Parrish et al., 2013), uranium (Adelani et al., 2012) and the sodium salt of a hybrid organic–inorganic polyoxovanadate cluster complex formed with arsanilate anions (Breen & Schmitt, 2008). Similarly, structures involving phenyl­arsonic acid are uncommon and are restricted to the parent acid [Shimada, 1960; Lloyd et al., 2008 (which includes the 4-fluoro-, 4-fluoro-3-nitro-, 3-amino-4-hy­droxy- and 3-amino-4-meth­oxy-derivatives)] and the salt adducts guanidinium phenyl­arsonate–guanidine–water (1/1/2) (Smith & Wermuth, 2010), bis­(guanidinium) phenyl­arsonate–water (1/2) (Latham et al., 2011) and ammonium 4-nitro­phenyl­arsonate (Yang et al., 2002).

Our 1:1 stoichiometric reaction of p-arsanilic acid with either ammonium carbonate or sodium carbonate in aqueous ethanol gave ammonium 4-amino­phenyl­arsonate monohydrate, (I), the one-dimensional coordination polymer catena-poly[[(4-amino­phenyl­arsonato-κO)di­aqua­sodium]-µ-aqua], (II), the structures and hydrogen-bonded packing modes for which are reported herein. Trihydrate complex (II) is the commonly employed form of the pharmaceutical compound atoxyl (Bosch & Rosich, 2008).

S2. Experimental

S2.1. Synthesis and crystallization

The title compounds were synthesized by heating together under reflux for 10 min, 4-amino­phenyl­arsonic acid (1 mmol, 217 mg) and either ammonium carbonate (1 mmol, 96 mg) [for (I)] or sodium carbonate (1 mmol, 106 mg) [for (II)] in 50% aqueous ethanol (30 ml). Room-temperature evaporation of the solutions gave colourless needles of both (I) and (II) from which specimens suitable for X-ray analyses were cleaved.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms involved in formal hydrogen-bonding inter­actions were located by difference methods and their positional and isotropic displacement parameters were allowed to ride, with N—H and O—H bond lengths restrained to 0.88±0.020 and 0.94±0.02 Å, respectively, and with U_iso(H) = 1.2U_eq(N) or 1.5U_eq(O). The aromatic H atoms were included in the refinement in calculated positions (C—H = 0.95 Å) and treated as riding, with U_iso(H) = 1.2U_eq(C). The Flack structure parameters (Flack, 1983), although not of relevance for the two molecular structures reported, were 0.002 (16) (937 Friedel pairs) for (I) and 0.020 (15) (991 Friedel pairs) for (II).

S3. Results and discussion

In the structure of ammonium salt (I), the ammonium cations, arsonate anions and water molecules (Fig. 1) inter­act through inter-species N—H···O and arsonate and water O—H···O hydrogen bonds (Table 2), giving two-dimensional layers lying parallel to (010). These layers are extended into three dimensions through hydrogen-bonding inter­actions involving the para-related amine group acting both as a donor and acceptor (Fig. 2). Among the inter­actions are examples of expanded cyclic motifs, e.g. graph set R₃³(10) (Etter et al., 1990) (one ammonium and two arsenate species) and R₅⁴(12) (two ammonium and two arsenate species, and a water molecule). The formation of two-dimensional layers in ammonium salts of carb­oxy­lic acids is consistent with the observation (Odendal et al., 2010), with ammonium benzoate among examples of ammonium and aminium salt structures from the Cambridge Structural Database (Version 5.34; Allen, 2002), as well as in the ammonium salts of 4-nitro­benzoic acid and 2,4-di­chloro­benzoic acid (Smith, 2014a). Expansion from two- into three-dimensional structures occurs only with hydrogen-bonding inter­actions between the layers through stereochemically sited donor/acceptor groups, such as found in (I) and in the ammonium 4-nitro­anthranilate monohydrate structure (Smith, 2014b).

In the coordination polymeric structure of the sodium salt of p-arsanilate, (II), the basic NaO₅ complex repeating unit (Fig. 3) comprises a single monodentate arsonate O-atom donor, two monodentate water O atoms (O1W and O3W) and two from the bridging water molecule (O2W and O2Wⁱ) [symmetry code: (i) -x+1/2, y, z-1/2)] (Table 3). The complex stereochemistry is very distorted square pyramidal, with an Na—O bond-length range of 2.376 (4)–2.482 (5) Å. The single bridging link gives a one-dimensional chain polymer structure extending along the crystallographic c direction (Fig. 4), with an Na1···Na1ⁱ separation of 4.452 (3) Å. Unlike what is observed in sodium salts of aromatic benzoic acids having coordinatively associative p-related substituent groups, e.g. sodium 4-nitro­anthranilate dihydrate (Smith, 2013), no inter-chain or inter-layer polymeric bonding extensions through dative inter­actions of the 4-amino group are present in (II). However, in the crystal, there are extensive hydrogen-bonding associations (Table 4) involving the coordinated water molecules and the arsonate group in O1—H···O links to primarily arsonate O-atom acceptors, with one exception (O2W—H···O1W), and to a single amine N-atom acceptor (O3W—H···N4). The amine H atoms form N—H···O hydrogen bonds to a water molecule (O3W), as well as to an arsonate O-atom acceptor (Table 4). These inter­actions form network linkages between the complex chains, generating a three-dimensional framework structure (Fig. 5).

The monoanionic arsenate groups in both (I) and (II) are similar in having delocalized As—O11 and As—O12 bonds, which are essentially equal [1.672 (3) and 1.677 (3) Å in (I), and 1.670 (3) and 1.659 (3) Å in (II), respectively]. These values are similar to the values of 1.656 (6) and 1.669 (6) Å in the zwitterionic parent acid (Nuttall & Hunter, 1996) and 1.655 (3) and 1.673 (3) in ammonium phenyl­arsonate (Yang et al., 2002). The As—O13(H) bonds in (I) and (II) are 1.746 (3) and 1.745 (4) Å, respectively, which can be compared with 1.737 (8) Å in the parent acid and 1.732 (2) Å in ammonium phenyl­arsonate.

The work reported here provides the first two examples of three-dimensional hydrogen-bonded structures in salts of p-arsanilic acid (the historically significant pharmaceutical arsenical, atoxyl), viz. an ammonium salt hydrate and a coordination polymeric sodium complex salt trihydrate.

Related literature

For related literature, see: Adelani et al. (2012); Allen (2002); Bosch & Rosich (2008); Breen & Schmitt (2008); Burke (1925); Ehrlich & Bertheim (1907); Etter et al. (1990); Flack (1983); Jolliffe (1993); Latham et al. (2011); Lesikar-Parrish, Neilson & Richards (2013); Lloyd et al. (2008); Nuttall & Hunter (1996); O'Neil (2001); Odendal et al. (2010); Shimada (1960, 1961); Smith (2013, 2014a, 2014b); Smith & Wermuth (2010); Steverding (2010); Thomas (1905); Yang et al. (2002).

Computing details

For both compounds, data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008). Program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) for (I); SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 2012) for (II). For both compounds, molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular configuration and atom-naming scheme for the p-arsonilate anion, the ammonium cation and the water molecule of solvation in (I). Inter-species hydrogen bonds are shown as dashed lines. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. The three-dimensional hydrogen-bonded framework structure of (I), viewed down the c-axial direction of the unit cell, showing hydrogen-bonding associations as dashed lines. Non-associative H atoms have been omitted. For symmetry codes, see Table 2.
	Fig. 3. The molecular configuration and atom-naming scheme for the complex unit in (II). Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) -x+1/2, y, z-1/2.]
	Fig. 4. The one-dimensional coordination polymeric chains in the structure of (II), extending along c. [Symmetry code: (i) -x+1/2, y, z-1/2.]
	Fig. 5. The hydrogen-bonding extensions in the three-dimensional structure of (II) in the unit cell, viewed down c, showing hydrogen bonds as dashed lines. Non-associative H atoms have been omitted. For symmetry codes, see Table 4.

(I) Ammonium 4-aminophenylarsonate monohydrate

Crystal data

NH4^+·C6H7AsNO3^−·H2O	F(000) = 512
Mr = 252.10	Dx = 1.610 Mg m^−3
Orthorhombic, Pca21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 1760 reflections
a = 11.4287 (18) Å	θ = 3.8–28.7°
b = 12.068 (2) Å	µ = 3.26 mm^−1
c = 7.5427 (13) Å	T = 200 K
V = 1040.3 (3) Å^3	Plate, colourless
Z = 4	0.35 × 0.35 × 0.08 mm

Data collection

Oxford Diffraction Gemini-S CCD-detector diffractometer	1506 independent reflections
Radiation source: Enhance (Mo) X-ray source	1385 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
Detector resolution: 16.077 pixels mm^-1	θmax = 26.0°, θmin = 3.4°
ω scans	h = −14→14
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013)	k = −14→14
Tmin = 0.670, Tmax = 0.980	l = −9→5
3581 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.067	w = 1/[σ^2(Fo^2) + (0.0368P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
1506 reflections	Δρmax = 0.33 e Å^−3
145 parameters	Δρmin = −0.55 e Å^−3
10 restraints	Absolute structure: Flack (1983), 937 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.002 (17)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
As1	0.37887 (3)	0.69813 (3)	0.83352 (9)	0.0184 (1)
O11	0.4879 (2)	0.6316 (2)	0.7310 (4)	0.0260 (9)
O12	0.2461 (2)	0.6448 (2)	0.7922 (4)	0.0299 (9)
O13	0.4115 (3)	0.6822 (3)	1.0582 (4)	0.0285 (10)
N4	0.3830 (3)	1.2004 (3)	0.7348 (6)	0.0287 (14)
C1	0.3801 (3)	0.8535 (3)	0.7905 (5)	0.0192 (13)
C2	0.4733 (3)	0.9058 (4)	0.7062 (5)	0.0257 (12)
C3	0.4747 (3)	1.0208 (3)	0.6881 (6)	0.0260 (14)
C4	0.3824 (3)	1.0852 (4)	0.7514 (6)	0.0210 (11)
C5	0.2882 (3)	1.0317 (3)	0.8357 (10)	0.0397 (14)
C6	0.2862 (3)	0.9167 (3)	0.8519 (9)	0.0364 (16)
O1W	0.3081 (3)	0.3203 (3)	1.0573 (5)	0.0356 (11)
N1	0.1296 (3)	0.4874 (3)	0.9783 (6)	0.0267 (12)
H2	0.53630	0.86290	0.66090	0.0310*
H3	0.53930	1.05580	0.63190	0.0310*
H5	0.22540	1.07440	0.88200	0.0480*
H6	0.22080	0.88120	0.90490	0.0440*
H13	0.347 (3)	0.676 (4)	1.136 (6)	0.0430*
H41	0.446 (3)	1.223 (4)	0.679 (6)	0.0340*
H42	0.319 (3)	1.220 (4)	0.681 (6)	0.0340*
H11W	0.374 (3)	0.328 (5)	1.128 (7)	0.0540*
H12W	0.344 (5)	0.298 (4)	0.953 (5)	0.0540*
H1A	0.168 (4)	0.544 (3)	0.929 (6)	0.0320*
H1B	0.081 (3)	0.455 (3)	0.905 (5)	0.0320*
H1C	0.083 (4)	0.519 (4)	1.056 (5)	0.0320*
H1D	0.182 (3)	0.440 (3)	1.019 (6)	0.0320*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
As1	0.0151 (2)	0.0190 (2)	0.0212 (2)	−0.0012 (1)	−0.0033 (3)	0.0012 (3)
O11	0.0264 (15)	0.0247 (15)	0.0270 (15)	0.0031 (13)	0.0003 (12)	−0.0028 (12)
O12	0.0246 (13)	0.0282 (14)	0.037 (2)	−0.0111 (12)	−0.0114 (13)	0.0069 (14)
O13	0.0193 (14)	0.046 (2)	0.0202 (16)	−0.0035 (15)	−0.0036 (13)	0.0061 (15)
N4	0.026 (2)	0.023 (2)	0.037 (3)	−0.0002 (16)	0.0050 (16)	0.0062 (16)
C1	0.0217 (18)	0.0179 (19)	0.018 (3)	−0.0023 (15)	−0.0028 (15)	−0.0024 (15)
C2	0.022 (2)	0.028 (2)	0.027 (2)	0.0048 (19)	0.0086 (17)	0.0001 (19)
C3	0.019 (2)	0.028 (2)	0.031 (3)	−0.0003 (19)	0.0076 (18)	0.011 (2)
C4	0.023 (2)	0.021 (2)	0.0190 (18)	−0.0007 (18)	0.0011 (15)	−0.0011 (17)
C5	0.030 (2)	0.028 (2)	0.061 (3)	0.0056 (18)	0.023 (3)	0.003 (3)
C6	0.0213 (17)	0.026 (2)	0.062 (4)	−0.0003 (17)	0.020 (3)	0.006 (3)
O1W	0.044 (2)	0.0333 (18)	0.0295 (18)	0.0020 (17)	−0.0048 (16)	−0.0056 (15)
N1	0.025 (2)	0.027 (2)	0.028 (2)	−0.0065 (18)	0.0053 (15)	−0.0051 (17)

Geometric parameters (Å, º)

As1—O11	1.672 (3)	N1—H1D	0.88 (4)
As1—O12	1.677 (2)	N1—H1A	0.89 (4)
As1—O13	1.746 (3)	C1—C6	1.396 (5)
As1—C1	1.903 (4)	C1—C2	1.392 (5)
O13—H13	0.95 (4)	C2—C3	1.395 (6)
O1W—H12W	0.93 (4)	C3—C4	1.395 (5)
O1W—H11W	0.93 (4)	C4—C5	1.407 (6)
N4—C4	1.396 (6)	C5—C6	1.393 (5)
N4—H42	0.87 (4)	C2—H2	0.9500
N4—H41	0.88 (4)	C3—H3	0.9500
N1—H1C	0.88 (4)	C5—H5	0.9500
N1—H1B	0.88 (4)	C6—H6	0.9500
O11—As1—O12	113.83 (13)	C2—C1—C6	119.5 (4)
O11—As1—O13	103.70 (15)	As1—C1—C2	122.0 (3)
O11—As1—C1	112.88 (14)	C1—C2—C3	120.3 (4)
O12—As1—O13	109.35 (16)	C2—C3—C4	120.8 (4)
O12—As1—C1	110.67 (13)	N4—C4—C3	121.4 (4)
O13—As1—C1	105.81 (17)	N4—C4—C5	120.1 (4)
As1—O13—H13	116 (2)	C3—C4—C5	118.5 (4)
H11W—O1W—H12W	99 (4)	C4—C5—C6	120.6 (4)
C4—N4—H41	111 (3)	C1—C6—C5	120.2 (4)
C4—N4—H42	108 (3)	C1—C2—H2	120.00
H41—N4—H42	113 (4)	C3—C2—H2	120.00
H1A—N1—H1B	113 (4)	C2—C3—H3	120.00
H1A—N1—H1C	104 (4)	C4—C3—H3	120.00
H1C—N1—H1D	117 (4)	C4—C5—H5	120.00
H1A—N1—H1D	108 (4)	C6—C5—H5	120.00
H1B—N1—H1C	103 (4)	C1—C6—H6	120.00
H1B—N1—H1D	111 (3)	C5—C6—H6	120.00
As1—C1—C6	118.4 (3)
O11—As1—C1—C2	−9.6 (4)	As1—C1—C6—C5	174.9 (5)
O11—As1—C1—C6	172.8 (4)	C2—C1—C6—C5	−2.8 (8)
O12—As1—C1—C2	−138.5 (3)	C1—C2—C3—C4	−1.0 (6)
O12—As1—C1—C6	44.0 (4)	C2—C3—C4—N4	179.7 (4)
O13—As1—C1—C2	103.1 (3)	C2—C3—C4—C5	0.6 (7)
O13—As1—C1—C6	−74.4 (4)	N4—C4—C5—C6	179.5 (5)
As1—C1—C2—C3	−175.5 (3)	C3—C4—C5—C6	−1.4 (8)
C6—C1—C2—C3	2.0 (6)	C4—C5—C6—C1	2.5 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O12	0.89 (4)	1.83 (4)	2.711 (5)	170 (4)
N1—H1B···O11^i	0.88 (4)	1.99 (4)	2.857 (5)	173 (4)
N1—H1C···O11^ii	0.88 (4)	2.06 (4)	2.909 (5)	162 (4)
N1—H1D···O1W	0.88 (4)	2.06 (4)	2.930 (5)	168 (4)
N4—H41···O13^iii	0.88 (4)	2.19 (4)	3.049 (5)	167 (4)
N4—H42···O1W^iv	0.87 (4)	2.11 (4)	2.942 (5)	161 (4)
O13—H13···O12^ii	0.95 (4)	1.63 (4)	2.562 (4)	167 (4)
O1W—H11W···O11^v	0.93 (4)	1.83 (4)	2.737 (4)	167 (5)
O1W—H12W···N4^vi	0.93 (4)	2.07 (4)	2.957 (6)	159 (5)

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

(II) catena-poly[[(4-aminophenylarsonato-κO)diaquasodium]-µ-aqua]

Crystal data

[Na(C6H7AsNO3)(H2O)3]	F(000) = 592
Mr = 293.08	Dx = 1.770 Mg m^−3
Orthorhombic, Pca21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 1282 reflections
a = 10.4069 (13) Å	θ = 3.9–28.4°
b = 13.6410 (17) Å	µ = 3.14 mm^−1
c = 7.7494 (9) Å	T = 200 K
V = 1100.1 (2) Å^3	Block, colourless
Z = 4	0.25 × 0.20 × 0.18 mm

Data collection

Oxford Diffraction Gemini-S CCD-detector diffractometer	1637 independent reflections
Radiation source: Enhance (Mo) X-ray source	1529 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
Detector resolution: 16.077 pixels mm^-1	θmax = 26.0°, θmin = 3.6°
ω scans	h = −11→12
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013)	k = −8→16
Tmin = 0.816, Tmax = 0.980	l = −9→9
2790 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.033	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.073	w = 1/[σ^2(Fo^2) + (0.0311P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max < 0.001
1637 reflections	Δρmax = 0.67 e Å^−3
163 parameters	Δρmin = −0.52 e Å^−3
10 restraints	Absolute structure: Flack (1983), 991 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.020 (15)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
As1	0.61030 (4)	0.28209 (3)	0.83909 (8)	0.0143 (1)
Na1	0.35537 (18)	0.40646 (15)	0.7093 (3)	0.0215 (6)
O1W	0.4553 (3)	0.5655 (3)	0.7299 (5)	0.0224 (11)
O2W	0.1892 (3)	0.4587 (3)	0.9084 (5)	0.0227 (11)
O3W	0.2208 (3)	0.2715 (3)	0.6391 (5)	0.0210 (12)
O11	0.7486 (3)	0.3375 (2)	0.8884 (4)	0.0201 (11)
O12	0.4826 (3)	0.3308 (3)	0.9344 (4)	0.0211 (11)
O13	0.5776 (4)	0.2987 (3)	0.6202 (5)	0.0247 (11)
N4	0.6110 (4)	−0.1607 (4)	0.9238 (6)	0.0230 (17)
C1	0.6174 (4)	0.1445 (4)	0.8751 (6)	0.0177 (16)
C2	0.7147 (5)	0.0870 (4)	0.8007 (6)	0.0193 (16)
C3	0.7128 (4)	−0.0130 (4)	0.8161 (7)	0.0193 (16)
C4	0.6126 (4)	−0.0592 (4)	0.9063 (7)	0.0173 (16)
C5	0.5199 (4)	−0.0018 (4)	0.9866 (6)	0.0190 (17)
C6	0.5207 (4)	0.0982 (4)	0.9698 (6)	0.0187 (16)
H2	0.78250	0.11780	0.73920	0.0230*
H3	0.77930	−0.05120	0.76570	0.0240*
H5	0.45510	−0.03230	1.05410	0.0230*
H6	0.45510	0.13620	1.02280	0.0230*
H11W	0.389 (4)	0.597 (4)	0.786 (6)	0.0340*
H12W	0.481 (5)	0.602 (3)	0.633 (5)	0.0340*
H13	0.647 (4)	0.300 (4)	0.546 (6)	0.0370*
H21W	0.122 (4)	0.451 (4)	0.830 (6)	0.0340*
H22W	0.213 (5)	0.5246 (18)	0.918 (7)	0.0340*
H31W	0.151 (4)	0.286 (4)	0.569 (6)	0.0320*
H32W	0.272 (5)	0.224 (3)	0.589 (8)	0.0320*
H41	0.642 (4)	−0.183 (4)	0.828 (4)	0.0270*
H42	0.540 (3)	−0.186 (4)	0.962 (7)	0.0270*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
As1	0.0129 (2)	0.0163 (2)	0.0138 (2)	−0.0013 (2)	−0.0018 (3)	0.0010 (3)
Na1	0.0219 (10)	0.0212 (11)	0.0215 (10)	0.0004 (9)	−0.0025 (9)	0.0008 (10)
O1W	0.0197 (19)	0.025 (2)	0.0225 (19)	0.0030 (16)	0.0018 (18)	0.0004 (18)
O2W	0.027 (2)	0.0199 (19)	0.0212 (18)	−0.0005 (17)	−0.0030 (15)	0.0009 (17)
O3W	0.019 (2)	0.022 (2)	0.022 (2)	−0.0005 (16)	−0.0007 (15)	−0.0005 (17)
O11	0.0136 (17)	0.0247 (19)	0.022 (2)	−0.0058 (15)	−0.0053 (14)	0.0045 (16)
O12	0.0182 (19)	0.026 (2)	0.0190 (19)	0.0023 (16)	0.0019 (15)	0.0000 (17)
O13	0.020 (2)	0.038 (2)	0.0160 (19)	−0.0033 (17)	−0.0016 (16)	0.0088 (18)
N4	0.024 (3)	0.018 (3)	0.027 (3)	−0.0016 (19)	0.007 (2)	0.003 (2)
C1	0.016 (2)	0.013 (2)	0.024 (4)	−0.0008 (18)	−0.004 (2)	0.003 (2)
C2	0.014 (2)	0.024 (3)	0.020 (3)	−0.003 (2)	0.0046 (19)	0.001 (2)
C3	0.019 (2)	0.021 (3)	0.018 (3)	0.0061 (19)	0.002 (2)	−0.002 (3)
C4	0.021 (3)	0.016 (3)	0.015 (2)	0.003 (2)	−0.0034 (19)	0.002 (2)
C5	0.014 (3)	0.023 (3)	0.020 (3)	0.002 (2)	0.004 (2)	0.002 (3)
C6	0.015 (3)	0.023 (3)	0.018 (2)	0.007 (2)	0.005 (2)	0.001 (2)

Geometric parameters (Å, º)

Na1—O1W	2.411 (4)	O13—H13	0.92 (4)
Na1—O2W	2.425 (4)	N4—C4	1.391 (8)
Na1—O3W	2.376 (4)	N4—H42	0.87 (4)
Na1—O12	2.421 (4)	N4—H41	0.87 (4)
Na1—O2W^i	2.482 (5)	C1—C6	1.397 (6)
As1—O11	1.670 (3)	C1—C2	1.405 (7)
As1—O12	1.659 (3)	C2—C3	1.370 (8)
As1—O13	1.745 (4)	C3—C4	1.405 (7)
As1—C1	1.899 (5)	C4—C5	1.390 (7)
O1W—H11W	0.92 (5)	C5—C6	1.370 (8)
O1W—H12W	0.94 (4)	C2—H2	0.9500
O2W—H21W	0.93 (4)	C3—H3	0.9500
O2W—H22W	0.94 (3)	C5—H5	0.9500
O3W—H31W	0.93 (4)	C6—H6	0.9500
O3W—H32W	0.92 (5)
O11—As1—O12	114.03 (16)	Na1—O3W—H32W	107 (3)
O11—As1—O13	109.38 (17)	H31W—O3W—H32W	111 (5)
O11—As1—C1	112.35 (16)	Na1—O3W—H31W	116 (3)
O12—As1—O13	102.98 (18)	As1—O13—H13	117 (3)
O12—As1—C1	111.20 (19)	C4—N4—H42	116 (4)
O13—As1—C1	106.2 (2)	H41—N4—H42	118 (5)
O1W—Na1—O2W	90.06 (14)	C4—N4—H41	105 (4)
O1W—Na1—O3W	165.12 (16)	As1—C1—C2	121.3 (4)
O1W—Na1—O12	95.74 (15)	As1—C1—C6	119.8 (4)
O1W—Na1—O2W^i	83.37 (14)	C2—C1—C6	118.9 (5)
O2W—Na1—O3W	87.31 (14)	C1—C2—C3	120.7 (5)
O2W—Na1—O12	93.26 (14)	C2—C3—C4	120.1 (5)
O2W—Na1—O2W^i	112.34 (14)	N4—C4—C3	120.3 (4)
O3W—Na1—O12	99.03 (15)	N4—C4—C5	120.6 (4)
O2W^i—Na1—O3W	84.10 (15)	C3—C4—C5	119.0 (5)
O2W^i—Na1—O12	154.36 (14)	C4—C5—C6	120.9 (4)
Na1—O2W—Na1^ii	130.30 (17)	C1—C6—C5	120.3 (4)
As1—O12—Na1	106.74 (16)	C1—C2—H2	120.00
Na1—O1W—H11W	97 (3)	C3—C2—H2	120.00
Na1—O1W—H12W	123 (3)	C2—C3—H3	120.00
H11W—O1W—H12W	110 (4)	C4—C3—H3	120.00
H21W—O2W—H22W	111 (5)	C4—C5—H5	120.00
Na1^ii—O2W—H21W	116 (3)	C6—C5—H5	120.00
Na1^ii—O2W—H22W	105 (3)	C1—C6—H6	120.00
Na1—O2W—H21W	95 (3)	C5—C6—H6	120.00
Na1—O2W—H22W	98 (3)
O11—As1—O12—Na1	111.88 (17)	O2W^i—Na1—O12—As1	−4.3 (5)
O13—As1—O12—Na1	−6.5 (2)	O1W—Na1—O2W^i—Na1^i	−155.4 (2)
C1—As1—O12—Na1	−119.9 (2)	O2W—Na1—O2W^i—Na1^i	−68.1 (3)
O11—As1—C1—C2	−53.3 (4)	O3W—Na1—O2W^i—Na1^i	16.6 (2)
O11—As1—C1—C6	130.1 (4)	O12—Na1—O2W^i—Na1^i	115.1 (3)
O12—As1—C1—C2	177.5 (4)	As1—C1—C2—C3	−174.7 (4)
O12—As1—C1—C6	0.9 (4)	C6—C1—C2—C3	2.0 (7)
O13—As1—C1—C2	66.2 (4)	As1—C1—C6—C5	175.5 (3)
O13—As1—C1—C6	−110.4 (4)	C2—C1—C6—C5	−1.2 (7)
O1W—Na1—O2W—Na1^ii	−111.2 (2)	C1—C2—C3—C4	0.3 (7)
O3W—Na1—O2W—Na1^ii	83.4 (2)	C2—C3—C4—N4	−179.3 (5)
O12—Na1—O2W—Na1^ii	−15.5 (2)	C2—C3—C4—C5	−3.3 (7)
O2W^i—Na1—O2W—Na1^ii	165.93 (19)	N4—C4—C5—C6	−179.9 (4)
O1W—Na1—O12—As1	−90.9 (2)	C3—C4—C5—C6	4.1 (7)
O2W—Na1—O12—As1	178.68 (19)	C4—C5—C6—C1	−1.8 (7)
O3W—Na1—O12—As1	90.9 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H41···O3W^iii	0.87 (4)	2.07 (4)	2.908 (6)	164 (5)
N4—H42···O13^iv	0.87 (4)	2.32 (5)	3.117 (6)	154 (4)
O13—H13···O11^v	0.92 (4)	1.71 (5)	2.604 (5)	161 (5)
O1W—H11W···O11^vi	0.92 (5)	1.89 (5)	2.808 (5)	177 (5)
O1W—H12W···O12^vii	0.94 (4)	1.83 (4)	2.768 (5)	175 (5)
O2W—H21W···O1W^vi	0.93 (4)	1.91 (4)	2.819 (5)	163 (4)
O2W—H22W···O11^vi	0.94 (3)	1.93 (3)	2.852 (5)	168 (5)
O3W—H31W···O12^i	0.93 (4)	1.84 (5)	2.766 (5)	173 (5)
O3W—H32W···N4^viii	0.92 (5)	1.97 (6)	2.852 (6)	160 (5)

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