Guanidinium 4-amino-benzoate.

In the title compound, CH(6)N(3) (+)·C(7)H(6)NO(2) (-), the cation and anion lie on crystallographic mirror planes. The 4-amino-benzoate anion is almost in a planar conformation with a maximum deviation of 0.024 (2) Å for the N atom. The bond length in the deprotonated carboxyl group is inter-mediate between those of normal single and double Csp(2)=O bonds, indicating delocalization of the charge over both O atoms of the COO(-) group. In the crystal, N-H⋯O hydrogen bonds assemble the ions in layers propagating in the bc plane. This structure is very similar to that of guanidinium benzoate.

Related literature

For a related structure, see: Pereira Silva et al. (2007 ▶). 4-Amino­benzoic acid has two known polymorphs, see: Gracin & Rasmuson (2004 ▶). For the potential applications of guanidine compounds in non-linear optics, see: Zyss et al. (1993 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

CH6N3 +·n class="Chemical">C7H6NO2 −

M = 196.22

Orthorhombic,

a = 14.9833 (4) Å

b = 8.0602 (2) Å

c = 8.4737 (2) Å

V = 1023.36 (4) Å3

Z = 4

Mo Kα radiation

μ = 0.10 mm−1

T = 293 K

0.33 × 0.19 × 0.15 mm

Data collection

Bruker APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ▶) T min = 0.898, T max = 0.986

19879 measured reflections

1323 independent reflections

960 reflections with I > 2σ(I)

R int = 0.026

Refinement

R[F 2 > 2σ(F 2)] = 0.037

wR(F 2) = 0.109

S = 1.04

1323 reflections

85 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.13 e Å−3

Δρmin = −0.20 e Å−3

Data collection: APEX2 (Bruker, 2003 ▶); cell refinement: SAIn class="Chemical">NT (Bruker, 2003 ▶); data reduction: SAINT; 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: SHELXL97.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681000396X/ds2019sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053681000396X/ds2019Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

CH6N3+·C7H6NO2−	F(000) = 416
Mr = 196.22	Dx = 1.274 Mg m−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 8009 reflections
a = 14.9833 (4) Å	θ = 2.8–27.5°
b = 8.0602 (2) Å	µ = 0.10 mm−1
c = 8.4737 (2) Å	T = 293 K
V = 1023.36 (4) Å3	Irregular edge, light brown
Z = 4	0.33 × 0.19 × 0.15 mm

Bruker APEX2 CCD area-detector diffractometer	1323 independent reflections
Radiation source: fine-focus sealed tube	960 reflections with I > 2σ(I)
graphite	Rint = 0.026
φ and ω scans	θmax = 28.1°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −18→19
Tmin = 0.898, Tmax = 0.986	k = −10→9
19879 measured reflections	l = −10→11

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.109	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ2(Fo2) + (0.051P)2 + 0.1635P] where P = (Fo2 + 2Fc2)/3
1323 reflections	(Δ/σ)max < 0.001
85 parameters	Δρmax = 0.13 e Å−3
0 restraints	Δρmin = −0.20 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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.

	x	y	z	Uiso*/Ueq
O1	0.34385 (6)	0.11290 (10)	−0.04842 (10)	0.0519 (3)
C1	0.43652 (10)	0.2500	0.13590 (17)	0.0390 (4)
C2	0.46854 (8)	0.10235 (14)	0.19926 (13)	0.0462 (3)
H2	0.4490	0.0019	0.1577	0.055*
C3	0.52869 (8)	0.10183 (16)	0.32253 (14)	0.0542 (3)
H3	0.5491	0.0015	0.3630	0.065*
C4	0.55904 (11)	0.2500	0.3867 (2)	0.0556 (5)
C5	0.37086 (10)	0.2500	0.00390 (17)	0.0391 (4)
N4	0.61881 (15)	0.2500	0.5120 (3)	0.0886 (7)
H4	0.6353 (13)	0.149 (3)	0.543 (2)	0.106*
N1	0.25025 (7)	0.10833 (13)	0.66469 (14)	0.0551 (3)
H1A	0.2845 (9)	0.1093 (16)	0.7576 (18)	0.066*
H1B	0.2285 (9)	0.016 (2)	0.6258 (17)	0.066*
N2	0.17018 (11)	0.2500	0.47745 (19)	0.0563 (4)
H2A	0.1493 (9)	0.147 (2)	0.4470 (16)	0.068*
C6	0.22330 (11)	0.2500	0.6031 (2)	0.0426 (4)

	U11	U22	U33	U12	U13	U23
O1	0.0705 (6)	0.0334 (4)	0.0519 (5)	−0.0031 (4)	−0.0139 (4)	−0.0006 (3)
C1	0.0415 (8)	0.0398 (8)	0.0358 (7)	0.000	0.0050 (6)	0.000
C2	0.0489 (6)	0.0455 (6)	0.0442 (6)	0.0021 (5)	0.0014 (5)	0.0013 (5)
C3	0.0530 (7)	0.0627 (8)	0.0467 (7)	0.0100 (6)	−0.0004 (5)	0.0089 (6)
C4	0.0443 (9)	0.0813 (14)	0.0411 (9)	0.000	−0.0018 (8)	0.000
C5	0.0460 (8)	0.0335 (8)	0.0380 (8)	0.000	0.0035 (7)	0.000
N4	0.0818 (13)	0.1110 (19)	0.0732 (13)	0.000	−0.0344 (11)	0.000
N1	0.0655 (7)	0.0379 (6)	0.0618 (7)	0.0026 (5)	−0.0206 (5)	−0.0012 (5)
N2	0.0656 (10)	0.0446 (9)	0.0587 (9)	0.000	−0.0226 (8)	0.000
C6	0.0419 (8)	0.0398 (8)	0.0460 (8)	0.000	−0.0036 (7)	0.000

O1—C5	1.2575 (11)	C4—N4	1.390 (3)
C1—C2i	1.3910 (13)	C5—O1i	1.2575 (11)
C1—C2	1.3910 (13)	N4—H4	0.89 (2)
C1—C5	1.490 (2)	N1—C6	1.3188 (13)
C2—C3	1.3796 (17)	N1—H1A	0.940 (15)
C2—H2	0.9300	N1—H1B	0.875 (16)
C3—C4	1.3886 (15)	N2—C6	1.329 (2)
C3—H3	0.9300	N2—H2A	0.923 (16)
C4—C3i	1.3886 (15)	C6—N1i	1.3188 (13)
C2i—C1—C2	117.65 (14)	O1—C5—O1i	122.98 (14)
C2i—C1—C5	121.18 (7)	O1—C5—C1	118.50 (7)
C2—C1—C5	121.18 (7)	O1i—C5—C1	118.50 (7)
C3—C2—C1	121.34 (11)	C4—N4—H4	113.7 (13)
C3—C2—H2	119.3	C6—N1—H1A	119.5 (8)
C1—C2—H2	119.3	C6—N1—H1B	118.1 (10)
C2—C3—C4	120.50 (12)	H1A—N1—H1B	121.7 (13)
C2—C3—H3	119.7	C6—N2—H2A	115.3 (9)
C4—C3—H3	119.7	N1i—C6—N1	119.95 (15)
C3—C4—C3i	118.64 (15)	N1i—C6—N2	120.02 (8)
C3—C4—N4	120.68 (8)	N1—C6—N2	120.02 (8)
C3i—C4—N4	120.68 (8)
C2i—C1—C2—C3	1.2 (2)	C2i—C1—C5—O1	−179.70 (13)
C5—C1—C2—C3	−179.36 (12)	C2—C1—C5—O1	0.8 (2)
C1—C2—C3—C4	−0.1 (2)	C2i—C1—C5—O1i	−0.8 (2)
C2—C3—C4—C3i	−1.0 (3)	C2—C1—C5—O1i	179.70 (13)
C2—C3—C4—N4	179.23 (16)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ii	0.940 (15)	1.869 (16)	2.8068 (14)	175.4 (13)
N1—H1B···O1iii	0.875 (16)	2.107 (16)	2.9032 (15)	151.0 (13)
N2—H2A···O1iii	0.923 (16)	2.099 (16)	2.9408 (8)	151.1 (12)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1i	0.940 (15)	1.869 (16)	2.8068 (14)	175.4 (13)
N1—H1B⋯O1ii	0.875 (16)	2.107 (16)	2.9032 (15)	151.0 (13)
N2—H2A⋯O1ii	0.923 (16)	2.099 (16)	2.9408 (8)	151.1 (12)

Symmetry codes: (i) ; (ii) .