Guanidinium phenyl­arsonate-guanidine-water (1/1/2)

In the structure of the title compound, CH₆N₃⁺·C₆H₆AsO₃^-·CH₅N₃·2H₂O, the phenyl­arsonate anion participates in two R₂²(8) cyclic hydrogen-bonding inter­actions, one with a guanidinium cation, the other with a guanidine mol­ecule. The anions are also bridged by the water mol­ecules, one of which completes a cyclic R₅³(9) hydrogen-bonding association with the guanidinum cation, conjoint with one of the three R₂²(8) associations about that ion, as well as forming an R₂¹(6) cyclic association with the guanidine mol­ecule. The result is a three-dimensional framework structure.

Key indicators

• Single-crystal X-ray study
• T = 200 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.019
• wR factor = 0.035
• Data-to-parameter ratio = 8.6

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT915_ALERT_3_B Low Friedel Pair Coverage ......................      39.37 Perc.

Alert level C
PLAT420_ALERT_2_C D-H Without Acceptor       N1B    -   H12B   ...          ?
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          2
PLAT042_ALERT_1_C Calc. and Reported MoietyFormula Strings  Differ          ?
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              C H6 N3
PLAT926_ALERT_1_C Reported and Calculated   R1 * 100.0 Differ by .      -0.12
PLAT927_ALERT_1_C Reported and Calculated  wR2 * 100.0 Differ by .      -0.34

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           25.99
           From the CIF: _reflns_number_total               2095
           Count of symmetry unique reflns         1505
           Completeness (_total/calc)            139.20%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       590
           Fraction of Friedel pairs measured     0.392
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          2
PLAT033_ALERT_4_G Flack x Parameter Value Deviates from Zero .....       0.02

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The guanidinium cation has the capacity to form extended hydrogen-bonded structures through its six trigonally disposed H-donor sites. This ability is best illustrated in the host–guest clathrate structures with 4,4'-biphenyldisulfonate (Swift et al., 1998, Swift & Ward, 1998) or the supramolecular rosette ribbons with HCO₃^- and terephthalic acid (Mak & Xue, 2000). The hydrogen-bonded structures found in the guanidinium salts of carboxylic acids are largely three-dimensional and usually feature cyclic associations involving either two N–H···O_carboxyl links [graph set R₂²(8) (Etter et al., 1990)] or three-centre N–H···O,O'_carboxyl links [graph set R²₁(6)]. Some examples of the structures of the guanidinium salts of monocyclic aromatic acids are those with pyromellitic acid (Sun et al., 2002), 3,5-dinitrosalicylic acid (Smith et al., 2001) and phenylacetic acid (Smith & Wermuth, 2010). This last compound has both types of cation-anion interaction but shows an unusual one-dimensional columnar structure. The structure of the guanidinium salt of phenylarsonic acid [benzenearsonic acid (O'Neil, 2001)] has not been previously reported.

Our 2:1 stoichiometric reaction of phenylarsonic acid with guanidinium carbonate aqueous propan-2-ol gave large, high-quality crystals of the title compound, the adduct hydrate CH₆N₃⁺ C₆H₆AsO₃^-. CH₅N₃. 2H₂O (I), the structure of which is reported here.

In (I) the phenylarsonate anion gives two R₂²(8) cyclic hydrogen-bonding interactions, one with a guanidinium cation (A), the other with a guanidine molecule (B), in which the second donor H atom is provided by the arsonate O–H group (Fig. 1). The anions are also bridged by the linked water molecules, one of which (O2W) completes a cyclic R₅³(9) hydrogen-bonding association with a guanidinum cation (Fig. 2) (Table 1). This ring is conjoint with one of the three R₂²(8) associations about the cation, whereas with the guanidine molecule there is one R₂²(8) and one R¹₂(6) association, also with O2W. The overall result is a three-dimensional framework structure (Fig. 3).

It is notable that the As environment has a total of eight As–H contacts both inter- and intra-molecular with a range of 2.95 (3)–3.15 (3) Å. Also, one of the H atoms of the guanidine cation (H12B) has no feasibly situated acceptor atom.

Related literature

For chemical data on phenylarsonic acid, see: O'Neil (2001). For related guanidinium structures, see: Smith et al. (2001); Smith & Wermuth (2010); Sun et al. (2002); Swift & Ward (1998); Swift et al. (1998); Mak & Xue (2000). For graph-set analysis, see: Etter et al. (1990).

S2. Experimental

The title compound was synthesized by heating together under reflux for 10 minutes, 1 mmol of phenylarsonic acid (benzenearsonic acid) and 0.5 mmol of guanidine carbonate in 50% aqueous propan-2-ol. After concentration to ca 30 ml, room temperature evaporation of the hot-filtered solution to moist dryness gave colourless plates of (I) (m.p. 505 K), from which a specimen suitable for X-ray analysis was cleaved.

S3. Refinement

Hydrogen atoms involved in hydrogen-bonding interactions were located by difference methods and their positional and isotropic displacement parameters were refined. The aromatic H atoms were included in the refinement in calculated positions (C–H = 0.93 Å) and treated as riding, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell refinement: CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON (Spek, 2009).

Figures

	Fig. 1. Molecular configuration and atom naming scheme for the guanidinium cation (A and the guanidine molecule B), the phenylarsonate anion and the two water molecules of solvation in (I). Inter-species hydrogen bonds are shown as dashed lines. Displacement ellipsoids are drawn at the 40% probability level.
	Fig. 2. The hydrogen-bonding extensions of the basic asymmetric unit in the structure of (I), showing hydrogen-bonding associations as dashed lines. For symmetry codes, see Table 1.
	Fig. 3. The hydrogen-bonded framework structure of (I) viewed down the b axial direction of the unit cell, showing hydrogen-bonding associations as dashed lines. Non-associative hydrogen atoms are deleted.

Guanidinium phenylarsonate–guanidine–water (1/1/2)

Crystal data

CH6N3^+·C6H6AsO3^−·CH5N3·2H2O	F(000) = 736
Mr = 356.23	Dx = 1.548 Mg m^−3
Monoclinic, Cc	Melting point: 505 K
Hall symbol: C -2yc	Mo Kα radiation, λ = 0.71073 Å
a = 18.6545 (14) Å	Cell parameters from 3772 reflections
b = 7.6394 (3) Å	θ = 3.1–28.7°
c = 12.6319 (10) Å	µ = 2.25 mm^−1
β = 121.856 (10)°	T = 200 K
V = 1529.0 (2) Å^3	Block, colourless
Z = 4	0.27 × 0.25 × 0.20 mm

Data collection

Oxford Diffraction Gemini-S CCD-detector diffractometer	2095 independent reflections
Radiation source: Enhance (Mo) X-ray source	1940 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.024
Detector resolution: 16.08 pixels mm^-1	θmax = 26.0°, θmin = 3.1°
ω scans	h = −22→21
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −9→9
Tmin = 0.935, Tmax = 0.985	l = −11→15
4919 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)] = 0.019	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.035	w = 1/[σ^2(Fo^2) + (0.0159P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.96	(Δ/σ)max = 0.002
2095 reflections	Δρmax = 0.17 e Å^−3
245 parameters	Δρmin = −0.22 e Å^−3
2 restraints	Absolute structure: Flack (1983), 590 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.020 (7)

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	0.85472 (1)	0.69726 (3)	0.45636 (2)	0.0162 (1)
O1	0.85598 (11)	0.8928 (2)	0.39683 (17)	0.0220 (6)
O2	0.79876 (11)	0.5495 (2)	0.34181 (17)	0.0223 (6)
O3	0.81253 (10)	0.7081 (2)	0.54592 (15)	0.0209 (6)
C1	0.96902 (16)	0.6103 (3)	0.5496 (2)	0.0214 (8)
C2	1.00375 (19)	0.5330 (4)	0.6658 (3)	0.0312 (10)
C3	1.0834 (2)	0.4638 (5)	0.7248 (4)	0.0393 (12)
C4	1.1311 (2)	0.4729 (5)	0.6705 (3)	0.0388 (11)
C5	1.0978 (2)	0.5496 (5)	0.5556 (4)	0.0423 (16)
C6	1.0164 (2)	0.6166 (5)	0.4950 (3)	0.0326 (11)
N1A	0.81112 (15)	1.0554 (3)	0.6380 (3)	0.0214 (8)
N2A	0.79667 (18)	1.3549 (4)	0.6207 (3)	0.0253 (9)
N3A	0.80233 (15)	1.1956 (4)	0.4697 (2)	0.0259 (8)
C1A	0.80313 (16)	1.2018 (4)	0.5759 (2)	0.0185 (8)
N1B	0.50840 (19)	0.4864 (5)	0.2386 (4)	0.0452 (11)
N2B	0.6296 (2)	0.6056 (4)	0.4032 (3)	0.0391 (12)
N3B	0.6265 (2)	0.5171 (5)	0.2284 (4)	0.0391 (11)
C1B	0.5899 (2)	0.5383 (4)	0.2899 (4)	0.0301 (11)
O1W	0.88312 (19)	0.7021 (3)	0.7987 (2)	0.0416 (10)
O2W	0.99736 (15)	0.9183 (4)	0.9723 (2)	0.0421 (8)
H2	0.97270	0.52800	0.70410	0.0370*
H3	1.10560	0.41020	0.80200	0.0470*
H4	1.18560	0.42720	0.71170	0.0470*
H5	1.12960	0.55670	0.51860	0.0510*
H6	0.99350	0.66650	0.41640	0.0390*
H21	0.737 (3)	0.538 (7)	0.301 (4)	0.042 (11)*
H11A	0.8076 (16)	0.956 (4)	0.606 (3)	0.036 (8)*
H12A	0.823 (2)	1.061 (4)	0.717 (3)	0.043 (10)*
H21A	0.7921 (16)	1.368 (4)	0.680 (3)	0.038 (7)*
H22A	0.7998 (16)	1.461 (4)	0.585 (3)	0.045 (8)*
H31A	0.8017 (17)	1.287 (4)	0.436 (3)	0.035 (8)*
H32A	0.8159 (13)	1.093 (3)	0.441 (2)	0.037 (6)*
H11B	0.486 (2)	0.501 (5)	0.285 (3)	0.048 (11)*
H12B	0.480 (2)	0.444 (5)	0.166 (4)	0.052 (12)*
H21B	0.599 (2)	0.613 (5)	0.437 (4)	0.053 (12)*
H22B	0.683 (2)	0.653 (4)	0.436 (3)	0.055 (9)*
H31B	0.5958 (18)	0.495 (4)	0.156 (3)	0.050 (9)*
H11W	0.8672 (19)	0.702 (4)	0.714 (3)	0.052 (9)*
H12W	0.859 (2)	0.610 (4)	0.809 (3)	0.046 (10)*
H21W	0.960 (2)	0.982 (5)	0.954 (3)	0.046 (12)*
H22W	0.973 (2)	0.830 (5)	0.950 (4)	0.048 (12)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
As1	0.0201 (1)	0.0152 (1)	0.0153 (1)	−0.0004 (2)	0.0107 (1)	−0.0003 (2)
O1	0.0286 (10)	0.0189 (10)	0.0231 (11)	−0.0003 (8)	0.0167 (9)	0.0020 (8)
O2	0.0206 (10)	0.0247 (10)	0.0215 (11)	−0.0028 (8)	0.0111 (8)	−0.0049 (8)
O3	0.0278 (10)	0.0226 (9)	0.0174 (10)	0.0002 (8)	0.0155 (8)	−0.0031 (8)
C1	0.0212 (14)	0.0191 (13)	0.0205 (15)	−0.0008 (11)	0.0087 (12)	−0.0026 (12)
C2	0.0302 (17)	0.0396 (18)	0.0248 (17)	0.0038 (14)	0.0153 (14)	0.0063 (14)
C3	0.034 (2)	0.051 (2)	0.027 (2)	0.0097 (18)	0.0121 (17)	0.0101 (18)
C4	0.0249 (19)	0.051 (2)	0.033 (2)	0.0132 (17)	0.0101 (15)	0.0051 (18)
C5	0.026 (2)	0.070 (3)	0.039 (3)	0.0116 (19)	0.0226 (19)	0.013 (2)
C6	0.0287 (19)	0.0407 (19)	0.0261 (18)	0.0037 (15)	0.0130 (14)	0.0105 (16)
N1A	0.0329 (14)	0.0147 (12)	0.0211 (14)	0.0015 (10)	0.0174 (12)	0.0009 (11)
N2A	0.0425 (18)	0.0191 (15)	0.0245 (16)	0.0001 (12)	0.0246 (14)	−0.0022 (12)
N3A	0.0440 (15)	0.0198 (12)	0.0223 (13)	0.0015 (12)	0.0233 (11)	0.0028 (12)
C1A	0.0165 (13)	0.0203 (14)	0.0167 (14)	−0.0022 (12)	0.0075 (11)	−0.0028 (13)
N1B	0.0262 (17)	0.061 (2)	0.046 (2)	−0.0091 (14)	0.0175 (16)	−0.0030 (17)
N2B	0.027 (2)	0.054 (2)	0.032 (2)	−0.0023 (15)	0.0127 (16)	0.0048 (15)
N3B	0.0340 (19)	0.049 (2)	0.031 (2)	−0.0045 (16)	0.0150 (17)	−0.0104 (17)
C1B	0.0252 (19)	0.027 (2)	0.034 (2)	−0.0006 (15)	0.0128 (19)	0.0063 (18)
O1W	0.068 (2)	0.0355 (17)	0.0222 (14)	−0.0275 (14)	0.0245 (14)	−0.0064 (13)
O2W	0.0281 (13)	0.0333 (14)	0.0532 (16)	0.0002 (12)	0.0134 (12)	−0.0182 (13)

Geometric parameters (Å, º)

As1—O1	1.6781 (17)	N2B—C1B	1.320 (5)
As1—O2	1.6921 (17)	N3B—C1B	1.287 (6)
As1—O3	1.687 (2)	N1B—H11B	0.89 (4)
As1—C1	1.930 (3)	N1B—H12B	0.85 (4)
O2—H21	0.99 (6)	N2B—H21B	0.88 (5)
O1W—H11W	0.95 (3)	N2B—H22B	0.93 (4)
O1W—H12W	0.88 (3)	N3B—H31B	0.80 (3)
O2W—H21W	0.78 (4)	C1—C2	1.385 (4)
O2W—H22W	0.78 (4)	C1—C6	1.379 (5)
N1A—C1A	1.329 (4)	C2—C3	1.369 (6)
N2A—C1A	1.332 (4)	C3—C4	1.383 (6)
N3A—C1A	1.335 (3)	C4—C5	1.373 (5)
N1A—H12A	0.90 (3)	C5—C6	1.388 (6)
N1A—H11A	0.85 (3)	C2—H2	0.9300
N2A—H21A	0.80 (3)	C3—H3	0.9300
N2A—H22A	0.94 (3)	C4—H4	0.9300
N3A—H31A	0.82 (3)	C5—H5	0.9300
N3A—H32A	0.95 (2)	C6—H6	0.9300
N1B—C1B	1.360 (6)
As1···H11A	3.16 (3)	As1···H32A	3.09 (2)
As1···H11W	3.14 (3)	As1···H12W^ii	3.02 (3)
As1···H22A^i	2.95 (3)	As1···H21A^iii	3.08 (3)
As1···H22B	3.09 (4)	As1···H21W^iii	3.15 (4)
O1—As1—O2	111.03 (9)	As1—C1—C6	118.4 (2)
O1—As1—O3	112.25 (9)	C2—C1—C6	118.7 (3)
O1—As1—C1	107.92 (11)	As1—C1—C2	122.8 (3)
O2—As1—O3	108.09 (10)	C1—C2—C3	120.5 (4)
O2—As1—C1	106.05 (10)	C2—C3—C4	120.6 (4)
O3—As1—C1	111.34 (10)	C3—C4—C5	119.7 (4)
As1—O2—H21	122 (3)	C4—C5—C6	119.6 (4)
H11W—O1W—H12W	107 (3)	C1—C6—C5	121.0 (3)
H21W—O2W—H22W	100 (4)	C3—C2—H2	120.00
H11A—N1A—H12A	119 (3)	C1—C2—H2	120.00
C1A—N1A—H11A	121 (2)	C2—C3—H3	120.00
C1A—N1A—H12A	120 (2)	C4—C3—H3	120.00
H21A—N2A—H22A	114 (3)	C5—C4—H4	120.00
C1A—N2A—H21A	126 (2)	C3—C4—H4	120.00
C1A—N2A—H22A	121 (2)	C6—C5—H5	120.00
H31A—N3A—H32A	116 (3)	C4—C5—H5	120.00
C1A—N3A—H32A	123.2 (14)	C5—C6—H6	119.00
C1A—N3A—H31A	119 (2)	C1—C6—H6	120.00
C1B—N1B—H11B	117 (2)	N2A—C1A—N3A	120.2 (3)
H11B—N1B—H12B	121 (4)	N1A—C1A—N2A	119.7 (3)
C1B—N1B—H12B	122 (3)	N1A—C1A—N3A	120.1 (3)
C1B—N2B—H22B	120 (2)	N2B—C1B—N3B	122.1 (4)
C1B—N2B—H21B	115 (3)	N1B—C1B—N2B	118.5 (4)
H21B—N2B—H22B	125 (4)	N1B—C1B—N3B	119.5 (4)
C1B—N3B—H31B	115 (3)
O1—As1—C1—C2	136.3 (2)	C6—C1—C2—C3	−0.2 (5)
O1—As1—C1—C6	−47.5 (2)	As1—C1—C6—C5	−177.4 (3)
O2—As1—C1—C2	−104.7 (2)	C2—C1—C6—C5	−1.0 (5)
O2—As1—C1—C6	71.6 (2)	C1—C2—C3—C4	1.3 (5)
O3—As1—C1—C2	12.7 (2)	C2—C3—C4—C5	−1.0 (6)
O3—As1—C1—C6	−171.1 (2)	C3—C4—C5—C6	−0.3 (6)
As1—C1—C2—C3	176.0 (3)	C4—C5—C6—C1	1.3 (6)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H21···N3B	0.99 (6)	1.77 (6)	2.753 (5)	180 (6)
N1A—H11A···O3	0.85 (3)	2.06 (3)	2.903 (3)	173 (3)
N1A—H12A···O1^iv	0.90 (3)	2.05 (3)	2.943 (4)	172 (3)
N2A—H21A···O2^iv	0.80 (3)	2.08 (3)	2.867 (4)	167 (3)
N2A—H22A···O3^v	0.94 (3)	2.00 (3)	2.925 (4)	167 (3)
N3A—H31A···O2^v	0.82 (3)	2.32 (3)	3.132 (3)	179 (5)
N3A—H32A···O1	0.95 (2)	1.91 (2)	2.859 (4)	174 (2)
N1B—H11B···O2W^vi	0.89 (4)	2.34 (3)	3.151 (5)	151 (3)
N2B—H21B···O2W^vi	0.88 (5)	2.18 (5)	3.026 (5)	163 (4)
N2B—H22B···O3	0.93 (4)	2.10 (4)	3.002 (4)	165 (3)
N3B—H31B···O2W^vii	0.80 (3)	2.15 (3)	2.935 (5)	169 (4)
O1W—H11W···O3	0.95 (3)	1.81 (3)	2.737 (3)	167 (4)
O1W—H12W···O2^viii	0.88 (3)	1.85 (4)	2.715 (4)	168 (4)
O2W—H21W···O1^iv	0.78 (4)	1.93 (4)	2.701 (4)	171 (4)
O2W—H22W···O1W	0.78 (4)	2.01 (4)	2.673 (4)	143 (4)

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