

Supporting information
![]() | Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536810025821/bv2147sup1.cif |
![]() | Structure factor file (CIF format) https://doi.org/10.1107/S1600536810025821/bv2147Isup2.hkl |
CCDC reference: 788346
Key indicators
- Single-crystal X-ray study
- T = 200 K
- Mean
(C-C) = 0.003 Å
- R factor = 0.040
- wR factor = 0.101
- Data-to-parameter ratio = 14.5
checkCIF/PLATON results
No syntax errors found
Alert level B PLAT230_ALERT_2_B Hirshfeld Test Diff for C2 -- C3 .. 7.01 su PLAT230_ALERT_2_B Hirshfeld Test Diff for C4 -- C5 .. 8.12 su
Alert level C PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for C11 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C1 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C21 PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) ..... 3 PLAT042_ALERT_1_C Calc. and Reported MoietyFormula Strings Differ ?
0 ALERT level A = In general: serious problem 2 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 5 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
The title compound was synthesized by heating together under reflux for 10 minutes 1 mmol of phenylacetic acid and 0.5 mmol of guanidinium carbonate in 50 ml of 50% ethanol-water. After concentration to ca 30 ml, room temperature evaporation of the hot-filtered solution gave a colourless powder which was recrystallized from a minimum volume of water, giving on total evaporation, crystal plates of (I) (m.p. 443 K), from which a specimen suitable for X-ray analysis was cleaved.
Hydrogen atoms involved in hydrogen-bonding interactions were located by difference methods and their positional and isotropic displacement parameters were refined. The H atoms were included in the refinement in calculated positions (C–Haromatic = 0.93 Å and C–Haliphatc = 0.97 Å) and treated as riding, with Uiso(H) = 1.2Ueq(C).
The known structures of the guanidinium salts of simple monocyclic aromatic carboxylic acids comsist of those with benzoic acid (Pereira Silva et al., 2007), 4-aminobenzoic acid (Pereira Silva et al., 2010), 4-nitrobenzoic acid (Kleb et al., 1998) and 3-nitrobenzoic acid (Smith & Wermuth, 2010). In these anhydrous structures the guanidinium cation is usually involved in cyclic hydrogen-bonding associations through N–H···Ocarboxyl links [graph sets R22(8) or R21(6) (Etter et al., 1990)] giving most commonly three-dimensional structures. The structure of the guanidinium salt of phenylacetic acid had not been previously reported so we carried out the 2:1 stoichiometric reaction of phenylacetic acid with guanidinium carbonate in aqueous ethanol solution, providing colourless crystals of the title compound, CH6N3+ C8H7O2- (I) when recrystallized from water.
In the structure of (I) (Figs. 1, 2), each guanidinium cation is involved in three cyclic hydrogen-bonding interactions with the carboxyl O-acceptors of three independent phenylacetate anions, one R22(8) and two R21(6). These result in un-associated one-dimensional columnar structures which extend down the 42 (c) axis in the tetragonal cell (Fig. 3). Within these columnar structures there are 86.5 Å3 solvent accessible voids which are large enough to accommodate water molecules but surprisingly do not, despite the sample having been obtained by recrystallization from water.
With the anion, the acetate substituent is close to normal to the plane of the benzene ring [torsion angle C2–C1–C11–C21, 86.98 (18)°]. Present in the benzene ring are unexplained high unidirectional displacement parameters for three atoms [C3, C4, C5: U11, 0.1009 (18), 0.185 (3), 0.1019 (18) Å2 respectively, cf. a typical value 0.0427 (9) Å2 for C2].
For the structures of simple monocyclic aromatic guanidinium carboxylates, see: Pereira Silva et al. (2007, 2010); Kleb et al. (1998); Smith & Wermuth (2010). For graph-set analysis, see: Etter et al. (1990). For related literature, see: Farrugia (1999).
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); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON (Spek, 2009).
CH6N3+·C8H7O2− | Dx = 1.167 Mg m−3 |
Mr = 195.22 | Melting point: 443 K |
Tetragonal, P42/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 4bc | Cell parameters from 2510 reflections |
a = 16.8418 (10) Å | θ = 3.1–28.6° |
c = 7.8372 (6) Å | µ = 0.09 mm−1 |
V = 2223.0 (3) Å3 | T = 200 K |
Z = 8 | Block, colourless |
F(000) = 832 | 0.30 × 0.25 × 0.20 mm |
Oxford Diffraction Gemini-S CCD-detector diffractometer | 1430 reflections with I > 2σ(I) |
Radiation source: Enhance (Mo) X-ray source | Rint = 0.027 |
Graphite monochromator | θmax = 26.0°, θmin = 3.1° |
ω scans | h = −20→18 |
7477 measured reflections | k = −10→20 |
2191 independent reflections | l = −9→8 |
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)] = 0.040 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.101 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.93 | w = 1/[σ2(Fo2) + (0.0592P)2] where P = (Fo2 + 2Fc2)/3 |
2191 reflections | (Δ/σ)max = 0.001 |
151 parameters | Δρmax = 0.14 e Å−3 |
0 restraints | Δρmin = −0.14 e Å−3 |
CH6N3+·C8H7O2− | Z = 8 |
Mr = 195.22 | Mo Kα radiation |
Tetragonal, P42/n | µ = 0.09 mm−1 |
a = 16.8418 (10) Å | T = 200 K |
c = 7.8372 (6) Å | 0.30 × 0.25 × 0.20 mm |
V = 2223.0 (3) Å3 |
Oxford Diffraction Gemini-S CCD-detector diffractometer | 1430 reflections with I > 2σ(I) |
7477 measured reflections | Rint = 0.027 |
2191 independent reflections |
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.101 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.93 | Δρmax = 0.14 e Å−3 |
2191 reflections | Δρmin = −0.14 e Å−3 |
151 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O21 | 0.64098 (7) | 0.43351 (6) | 0.19316 (12) | 0.0534 (4) | |
O22 | 0.62981 (7) | 0.44279 (6) | −0.08684 (12) | 0.0518 (4) | |
C1 | 0.61757 (8) | 0.59370 (8) | 0.25158 (18) | 0.0364 (5) | |
C2 | 0.68820 (9) | 0.61788 (9) | 0.3219 (2) | 0.0510 (6) | |
C3 | 0.69086 (15) | 0.64720 (11) | 0.4853 (3) | 0.0775 (9) | |
C4 | 0.6222 (2) | 0.65222 (12) | 0.5811 (2) | 0.0918 (11) | |
C5 | 0.55179 (15) | 0.62730 (13) | 0.5105 (3) | 0.0817 (9) | |
C6 | 0.54971 (10) | 0.59874 (10) | 0.3487 (2) | 0.0554 (6) | |
C11 | 0.61473 (11) | 0.56093 (9) | 0.07399 (18) | 0.0550 (6) | |
C21 | 0.62985 (8) | 0.47232 (9) | 0.05979 (17) | 0.0378 (5) | |
N1G | 0.77589 (11) | 0.40624 (9) | 0.41545 (18) | 0.0537 (5) | |
N2G | 0.77186 (10) | 0.40368 (9) | 0.70667 (17) | 0.0517 (5) | |
N3G | 0.66128 (8) | 0.43990 (8) | 0.55565 (18) | 0.0445 (5) | |
C1G | 0.73652 (9) | 0.41692 (8) | 0.55946 (17) | 0.0381 (5) | |
H2 | 0.73470 | 0.61440 | 0.25830 | 0.0610* | |
H3 | 0.73900 | 0.66370 | 0.53150 | 0.0930* | |
H4 | 0.62360 | 0.67210 | 0.69180 | 0.1100* | |
H5 | 0.50520 | 0.63000 | 0.57400 | 0.0980* | |
H6 | 0.50160 | 0.58230 | 0.30260 | 0.0670* | |
H11 | 0.65390 | 0.58860 | 0.00530 | 0.0660* | |
H12 | 0.56290 | 0.57230 | 0.02590 | 0.0660* | |
H11G | 0.8248 (12) | 0.3924 (10) | 0.4193 (18) | 0.054 (5)* | |
H12G | 0.7504 (10) | 0.4141 (10) | 0.321 (2) | 0.063 (5)* | |
H21G | 0.7451 (10) | 0.4104 (9) | 0.795 (2) | 0.049 (5)* | |
H22G | 0.8201 (12) | 0.3872 (10) | 0.710 (2) | 0.061 (6)* | |
H31G | 0.6432 (9) | 0.4549 (9) | 0.453 (2) | 0.049 (5)* | |
H32G | 0.6410 (10) | 0.4547 (10) | 0.651 (2) | 0.055 (5)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O21 | 0.0885 (9) | 0.0400 (6) | 0.0317 (6) | 0.0054 (6) | −0.0136 (5) | −0.0003 (5) |
O22 | 0.0728 (8) | 0.0548 (7) | 0.0279 (6) | −0.0017 (6) | 0.0036 (5) | −0.0026 (5) |
C1 | 0.0399 (8) | 0.0297 (8) | 0.0397 (8) | 0.0033 (7) | −0.0008 (7) | 0.0028 (6) |
C2 | 0.0427 (9) | 0.0458 (10) | 0.0646 (11) | −0.0026 (8) | −0.0051 (8) | 0.0073 (8) |
C3 | 0.1009 (18) | 0.0509 (12) | 0.0807 (15) | −0.0161 (12) | −0.0466 (13) | 0.0084 (11) |
C4 | 0.185 (3) | 0.0493 (12) | 0.0411 (11) | 0.0059 (15) | −0.0096 (14) | −0.0145 (9) |
C5 | 0.1019 (18) | 0.0733 (14) | 0.0699 (14) | 0.0135 (13) | 0.0366 (13) | −0.0137 (12) |
C6 | 0.0406 (10) | 0.0558 (11) | 0.0698 (12) | 0.0006 (8) | 0.0068 (8) | −0.0051 (9) |
C11 | 0.0797 (13) | 0.0446 (9) | 0.0406 (9) | 0.0064 (9) | −0.0023 (8) | 0.0044 (7) |
C21 | 0.0400 (8) | 0.0445 (9) | 0.0288 (8) | 0.0002 (7) | 0.0003 (6) | 0.0004 (7) |
N1G | 0.0462 (9) | 0.0832 (11) | 0.0318 (8) | 0.0094 (8) | 0.0017 (7) | 0.0011 (7) |
N2G | 0.0433 (9) | 0.0805 (11) | 0.0312 (8) | 0.0052 (8) | −0.0022 (7) | −0.0033 (7) |
N3G | 0.0449 (8) | 0.0599 (9) | 0.0288 (8) | 0.0051 (6) | 0.0005 (6) | 0.0030 (6) |
C1G | 0.0415 (9) | 0.0413 (8) | 0.0314 (8) | −0.0044 (7) | −0.0011 (7) | −0.0003 (6) |
O21—C21 | 1.2470 (17) | C1—C2 | 1.373 (2) |
O22—C21 | 1.2522 (17) | C2—C3 | 1.373 (3) |
N1G—C1G | 1.321 (2) | C3—C4 | 1.381 (4) |
N2G—C1G | 1.317 (2) | C4—C5 | 1.374 (4) |
N3G—C1G | 1.325 (2) | C5—C6 | 1.357 (3) |
N1G—H11G | 0.86 (2) | C11—C21 | 1.518 (2) |
N1G—H12G | 0.866 (16) | C2—H2 | 0.9300 |
N2G—H21G | 0.834 (16) | C3—H3 | 0.9300 |
N2G—H22G | 0.86 (2) | C4—H4 | 0.9300 |
N3G—H31G | 0.897 (16) | C5—H5 | 0.9300 |
N3G—H32G | 0.859 (16) | C6—H6 | 0.9300 |
C1—C6 | 1.376 (2) | C11—H12 | 0.9700 |
C1—C11 | 1.498 (2) | C11—H11 | 0.9700 |
C1G—N1G—H12G | 117.4 (11) | O21—C21—O22 | 124.14 (14) |
H11G—N1G—H12G | 123.3 (15) | C1—C2—H2 | 120.00 |
C1G—N1G—H11G | 119.3 (10) | C3—C2—H2 | 120.00 |
C1G—N2G—H22G | 120.6 (11) | C2—C3—H3 | 120.00 |
H21G—N2G—H22G | 122.0 (15) | C4—C3—H3 | 120.00 |
C1G—N2G—H21G | 117.4 (11) | C5—C4—H4 | 120.00 |
C1G—N3G—H32G | 116.5 (11) | C3—C4—H4 | 121.00 |
H31G—N3G—H32G | 124.3 (15) | C4—C5—H5 | 120.00 |
C1G—N3G—H31G | 115.3 (10) | C6—C5—H5 | 120.00 |
C2—C1—C6 | 118.65 (14) | C1—C6—H6 | 119.00 |
C2—C1—C11 | 120.66 (13) | C5—C6—H6 | 119.00 |
C6—C1—C11 | 120.68 (14) | C21—C11—H11 | 109.00 |
C1—C2—C3 | 120.62 (16) | C21—C11—H12 | 108.00 |
C2—C3—C4 | 120.1 (2) | H11—C11—H12 | 108.00 |
C3—C4—C5 | 119.00 (18) | C1—C11—H11 | 108.00 |
C4—C5—C6 | 120.5 (2) | C1—C11—H12 | 108.00 |
C1—C6—C5 | 121.17 (17) | N2G—C1G—N3G | 120.08 (14) |
C1—C11—C21 | 115.15 (12) | N1G—C1G—N2G | 119.89 (15) |
O21—C21—C11 | 118.63 (12) | N1G—C1G—N3G | 120.02 (14) |
O22—C21—C11 | 117.24 (12) | ||
C6—C1—C2—C3 | −0.6 (2) | C1—C2—C3—C4 | 0.4 (3) |
C11—C1—C2—C3 | −179.37 (15) | C2—C3—C4—C5 | 0.2 (3) |
C2—C1—C6—C5 | 0.3 (2) | C3—C4—C5—C6 | −0.5 (3) |
C11—C1—C6—C5 | 179.08 (16) | C4—C5—C6—C1 | 0.2 (3) |
C2—C1—C11—C21 | 86.98 (18) | C1—C11—C21—O21 | 2.0 (2) |
C6—C1—C11—C21 | −91.75 (18) | C1—C11—C21—O22 | −178.42 (13) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1G—H11G···O22i | 0.86 (2) | 2.02 (2) | 2.876 (2) | 173.9 (15) |
N1G—H12G···O21 | 0.866 (16) | 2.123 (17) | 2.900 (2) | 149.0 (15) |
N2G—H21G···O22ii | 0.834 (16) | 2.219 (17) | 2.9625 (19) | 148.5 (15) |
N2G—H22G···O21i | 0.86 (2) | 1.97 (2) | 2.827 (2) | 172.6 (15) |
N3G—H31G···O21 | 0.897 (16) | 2.068 (16) | 2.8634 (17) | 147.2 (13) |
N3G—H32G···O22ii | 0.859 (16) | 2.073 (16) | 2.8520 (17) | 150.5 (15) |
Symmetry codes: (i) y+1/2, −x+1, z+1/2; (ii) x, y, z+1. |
Experimental details
Crystal data | |
Chemical formula | CH6N3+·C8H7O2− |
Mr | 195.22 |
Crystal system, space group | Tetragonal, P42/n |
Temperature (K) | 200 |
a, c (Å) | 16.8418 (10), 7.8372 (6) |
V (Å3) | 2223.0 (3) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.30 × 0.25 × 0.20 |
Data collection | |
Diffractometer | Oxford Diffraction Gemini-S CCD-detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7477, 2191, 1430 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.101, 0.93 |
No. of reflections | 2191 |
No. of parameters | 151 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.14, −0.14 |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
N1G—H11G···O22i | 0.86 (2) | 2.02 (2) | 2.876 (2) | 173.9 (15) |
N1G—H12G···O21 | 0.866 (16) | 2.123 (17) | 2.900 (2) | 149.0 (15) |
N2G—H21G···O22ii | 0.834 (16) | 2.219 (17) | 2.9625 (19) | 148.5 (15) |
N2G—H22G···O21i | 0.86 (2) | 1.97 (2) | 2.827 (2) | 172.6 (15) |
N3G—H31G···O21 | 0.897 (16) | 2.068 (16) | 2.8634 (17) | 147.2 (13) |
N3G—H32G···O22ii | 0.859 (16) | 2.073 (16) | 2.8520 (17) | 150.5 (15) |
Symmetry codes: (i) y+1/2, −x+1, z+1/2; (ii) x, y, z+1. |
The known structures of the guanidinium salts of simple monocyclic aromatic carboxylic acids comsist of those with benzoic acid (Pereira Silva et al., 2007), 4-aminobenzoic acid (Pereira Silva et al., 2010), 4-nitrobenzoic acid (Kleb et al., 1998) and 3-nitrobenzoic acid (Smith & Wermuth, 2010). In these anhydrous structures the guanidinium cation is usually involved in cyclic hydrogen-bonding associations through N–H···Ocarboxyl links [graph sets R22(8) or R21(6) (Etter et al., 1990)] giving most commonly three-dimensional structures. The structure of the guanidinium salt of phenylacetic acid had not been previously reported so we carried out the 2:1 stoichiometric reaction of phenylacetic acid with guanidinium carbonate in aqueous ethanol solution, providing colourless crystals of the title compound, CH6N3+ C8H7O2- (I) when recrystallized from water.
In the structure of (I) (Figs. 1, 2), each guanidinium cation is involved in three cyclic hydrogen-bonding interactions with the carboxyl O-acceptors of three independent phenylacetate anions, one R22(8) and two R21(6). These result in un-associated one-dimensional columnar structures which extend down the 42 (c) axis in the tetragonal cell (Fig. 3). Within these columnar structures there are 86.5 Å3 solvent accessible voids which are large enough to accommodate water molecules but surprisingly do not, despite the sample having been obtained by recrystallization from water.
With the anion, the acetate substituent is close to normal to the plane of the benzene ring [torsion angle C2–C1–C11–C21, 86.98 (18)°]. Present in the benzene ring are unexplained high unidirectional displacement parameters for three atoms [C3, C4, C5: U11, 0.1009 (18), 0.185 (3), 0.1019 (18) Å2 respectively, cf. a typical value 0.0427 (9) Å2 for C2].