Benzamidinium 2-meth-oxy-benzoate.

The title mol-ecular salt, C7H9N2 (+.)C8H7O3 (-), was synthesized by reaction between benzamidine (benzene-carboximidamide) and 2-meth-oxy-benzoic acid. In the cation, the amidinium group has two similar C-N bonds [1.3070 (17) and 1.3145 (16) Å] and is almost coplanar with the benzene ring, making a dihedral angle of 5.34 (12)°. In the anion, the meth-oxy substituent forces the carboxyl-ate group to be twisted by 69.45 (6)° with respect to the plane of the aromatic fragment. In the crystal, the components are connected by two N(+)-H⋯O(-) (±)CAHB (charge-assisted hydrogen bonds), forming centrosymmetric ionic dimers with graph-set motif R 2 (2)(8). These ionic dimers are then joined in ribbons running along the b-axis direction by another R 4 (2)(8) motif involving the remaining N(+)-H⋯O(-) hydrogen bonds. Remarkably, at variance with the well known carb-oxy-lic dimer R 2 (2)(8) motif, the carboxyl-ate-amidinium pair is not planar, the dihedral angle between the planes defined by the CN2 (+) and CO2 (-) atoms being 18.57 (12)°.

Related literature

For the biological and pharmacological relevance of benzamidine, see: Powers & Harper (1999 ▶). For structural analysis of proton-transfer adducts containing mol­ecules of biological inter­est, see: n class="Chemical">Portalone (2010 ▶, 2013 ▶). For the supra­molecular association in proton-transfer adducts containing benzamidinium cations, see: Portalone (2010 ▶, 2012 ▶, 2013 ▶); Irrera & Portalone (2012 ▶, 2013 ▶); Irrera et al. (2012 ▶). For 2-meth­oxy­benzoic acid derivatives, see: Portalone (2011 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C7H9N2 +·n class="Chemical">C8H7O3 −

M = 272.30

Triclinic,

a = 7.5154 (3) Å

b = 9.1393 (4) Å

c = 11.6498 (5) Å

α = 69.612 (3)°

β = 80.500 (5)°

γ = 72.482 (4)°

V = 713.63 (6) Å3

Z = 2

Mo Kα radiation

μ = 0.09 mm−1

T = 298 K

0.12 × 0.09 × 0.05 mm

Data collection

Agilent Xcalibur Sapphire3 diffractometer

Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T min = 0.989, T max = 0.996

20559 measured reflections

4332 independent reflections

3188 reflections with I > 2σ(I)

R int = 0.025

Refinement

R[F 2 > 2σ(F 2)] = 0.062

wR(F 2) = 0.161

S = 1.05

4332 reflections

199 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.38 e Å−3

Δρmin = −0.18 e Å−3

Data collection: CrysAlis PRO (Agilent, 2011 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813016395/nk2209sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813016395/nk2209Isup2.hkl

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

C7H9N2+·C8H7O3−	Z = 2
Mr = 272.30	F(000) = 288
Triclinic, P1	Dx = 1.267 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 7.5154 (3) Å	Cell parameters from 9004 reflections
b = 9.1393 (4) Å	θ = 3.2–32.5°
c = 11.6498 (5) Å	µ = 0.09 mm−1
α = 69.612 (3)°	T = 298 K
β = 80.500 (5)°	Tablets, colourless
γ = 72.482 (4)°	0.12 × 0.09 × 0.05 mm
V = 713.63 (6) Å3

Agilent Xcalibur Sapphire3 diffractometer	4332 independent reflections
Radiation source: Enhance (Mo) X-ray Source	3188 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.025
Detector resolution: 16.0696 pixels mm-1	θmax = 30.5°, θmin = 3.2°
ω and φ scans	h = −10→10
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −13→13
Tmin = 0.989, Tmax = 0.996	l = −16→16
20559 measured reflections

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)] = 0.062	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.161	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ2(Fo2) + (0.0812P)2 + 0.1295P] where P = (Fo2 + 2Fc2)/3
4332 reflections	(Δ/σ)max < 0.001
199 parameters	Δρmax = 0.38 e Å−3
0 restraints	Δρmin = −0.18 e Å−3

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
N1	−0.44074 (18)	0.33628 (15)	0.94036 (13)	0.0426 (3)
H1A	−0.369 (3)	0.355 (2)	0.9866 (17)	0.052 (5)*
H1B	−0.550 (3)	0.403 (2)	0.9196 (17)	0.053 (5)*
N2	−0.21153 (17)	0.11282 (17)	0.93377 (13)	0.0464 (3)
H2A	−0.139 (3)	0.138 (2)	0.9810 (17)	0.055 (5)*
H2B	−0.167 (3)	0.022 (3)	0.9197 (18)	0.059 (5)*
C1	−0.50196 (17)	0.16439 (15)	0.84181 (11)	0.0319 (3)
C2	−0.6776 (2)	0.2674 (2)	0.81080 (18)	0.0531 (4)
H2	−0.7178	0.3693	0.8281	0.064*
C3	−0.7954 (2)	0.2254 (2)	0.75542 (18)	0.0602 (5)
H3	−0.9172	0.2986	0.7333	0.072*
C4	−0.7414 (2)	0.0816 (2)	0.73164 (15)	0.0508 (4)
H4	−0.8254	0.0522	0.6939	0.061*
C5	−0.5678 (2)	−0.0216 (2)	0.76121 (16)	0.0504 (4)
H5	−0.5291	−0.1233	0.7435	0.060*
C6	−0.4480 (2)	0.01930 (18)	0.81621 (14)	0.0418 (3)
H6	−0.3257	−0.0539	0.8369	0.050*
C7	−0.38026 (17)	0.20627 (15)	0.90698 (12)	0.0323 (3)
O1	−0.24816 (15)	0.39582 (13)	1.09618 (11)	0.0513 (3)
O2	−0.00870 (15)	0.18920 (14)	1.08560 (11)	0.0536 (3)
O3	−0.24579 (19)	0.2238 (2)	1.37136 (12)	0.0694 (4)
C8	−0.00944 (18)	0.31556 (15)	1.23202 (12)	0.0335 (3)
C9	−0.0897 (2)	0.2793 (2)	1.35187 (14)	0.0434 (3)
C10	−0.0097 (3)	0.2988 (2)	1.44339 (15)	0.0572 (4)
H10	−0.0654	0.2737	1.5268	0.069*
C11	0.1493 (3)	0.3540 (2)	1.41503 (17)	0.0578 (5)
H11	0.2044	0.3678	1.4790	0.069*
C12	0.2300 (3)	0.3895 (2)	1.29805 (18)	0.0567 (4)
H12	0.3417	0.4281	1.2788	0.068*
C13	0.1494 (2)	0.3694 (2)	1.20632 (14)	0.0466 (4)
H13	0.2066	0.3940	1.1233	0.056*
C14	−0.09582 (18)	0.29772 (15)	1.13074 (12)	0.0335 (3)
C15	−0.3237 (4)	0.1697 (4)	1.4934 (2)	0.0938 (8)
H15A	−0.2241 (19)	0.083 (2)	1.5466 (11)	0.141*
H15B	−0.430 (3)	0.123 (2)	1.4938 (3)	0.141*
H15C	−0.372 (3)	0.2639 (17)	1.5268 (9)	0.141*

	U11	U22	U33	U12	U13	U23
N1	0.0387 (6)	0.0361 (6)	0.0566 (8)	0.0057 (5)	−0.0185 (5)	−0.0255 (6)
N2	0.0370 (6)	0.0443 (7)	0.0641 (8)	0.0087 (5)	−0.0192 (6)	−0.0341 (7)
C1	0.0328 (6)	0.0316 (6)	0.0304 (6)	−0.0023 (5)	−0.0065 (5)	−0.0122 (5)
C2	0.0485 (8)	0.0434 (8)	0.0714 (11)	0.0097 (7)	−0.0279 (8)	−0.0309 (8)
C3	0.0469 (9)	0.0595 (10)	0.0779 (12)	0.0077 (8)	−0.0332 (8)	−0.0317 (9)
C4	0.0538 (9)	0.0555 (9)	0.0506 (9)	−0.0146 (7)	−0.0188 (7)	−0.0189 (7)
C5	0.0590 (9)	0.0429 (8)	0.0573 (9)	−0.0076 (7)	−0.0158 (7)	−0.0253 (7)
C6	0.0410 (7)	0.0373 (7)	0.0483 (8)	0.0006 (6)	−0.0120 (6)	−0.0202 (6)
C7	0.0325 (6)	0.0305 (6)	0.0331 (6)	−0.0015 (5)	−0.0057 (5)	−0.0133 (5)
O1	0.0498 (6)	0.0453 (6)	0.0616 (7)	0.0158 (5)	−0.0293 (5)	−0.0328 (5)
O2	0.0462 (6)	0.0537 (7)	0.0690 (7)	0.0137 (5)	−0.0211 (5)	−0.0442 (6)
O3	0.0628 (8)	0.1107 (12)	0.0494 (7)	−0.0439 (8)	0.0064 (6)	−0.0300 (7)
C8	0.0341 (6)	0.0297 (6)	0.0363 (6)	0.0028 (5)	−0.0105 (5)	−0.0156 (5)
C9	0.0415 (7)	0.0506 (8)	0.0409 (7)	−0.0066 (6)	−0.0066 (6)	−0.0208 (6)
C10	0.0624 (10)	0.0752 (12)	0.0384 (8)	−0.0115 (9)	−0.0104 (7)	−0.0258 (8)
C11	0.0645 (11)	0.0638 (11)	0.0548 (10)	−0.0087 (9)	−0.0253 (8)	−0.0279 (8)
C12	0.0536 (9)	0.0614 (10)	0.0652 (11)	−0.0192 (8)	−0.0166 (8)	−0.0232 (9)
C13	0.0472 (8)	0.0541 (9)	0.0420 (8)	−0.0150 (7)	−0.0045 (6)	−0.0175 (7)
C14	0.0344 (6)	0.0301 (6)	0.0366 (6)	−0.0001 (5)	−0.0088 (5)	−0.0156 (5)
C15	0.0826 (16)	0.144 (2)	0.0608 (13)	−0.0546 (17)	0.0201 (12)	−0.0299 (14)

N1—C7	1.3070 (17)	O1—C14	1.2488 (15)
N1—H1A	0.913 (19)	O2—C14	1.2441 (16)
N1—H1B	0.87 (2)	O3—C9	1.369 (2)
N2—C7	1.3145 (16)	O3—C15	1.421 (3)
N2—H2A	0.959 (19)	C8—C13	1.375 (2)
N2—H2B	0.86 (2)	C8—C9	1.394 (2)
C1—C6	1.3869 (19)	C8—C14	1.5135 (17)
C1—C2	1.3898 (19)	C9—C10	1.393 (2)
C1—C7	1.4838 (18)	C10—C11	1.381 (3)
C2—C3	1.383 (2)	C10—H10	0.9700
C2—H2	0.9700	C11—C12	1.367 (3)
C3—C4	1.366 (2)	C11—H11	0.9700
C3—H3	0.9700	C12—C13	1.399 (2)
C4—C5	1.375 (2)	C12—H12	0.9700
C4—H4	0.9700	C13—H13	0.9700
C5—C6	1.386 (2)	C15—H15A	1.0120
C5—H5	0.9700	C15—H15B	1.0120
C6—H6	0.9700	C15—H15C	1.0120
C7—N1—H1A	119.2 (12)	C13—C8—C9	119.07 (13)
C7—N1—H1B	120.3 (12)	C13—C8—C14	120.07 (12)
H1A—N1—H1B	120.5 (17)	C9—C8—C14	120.86 (12)
C7—N2—H2A	119.6 (11)	O3—C9—C10	124.03 (15)
C7—N2—H2B	123.2 (13)	O3—C9—C8	115.99 (13)
H2A—N2—H2B	116.7 (17)	C10—C9—C8	119.97 (15)
C6—C1—C2	118.65 (13)	C11—C10—C9	119.83 (16)
C6—C1—C7	121.19 (11)	C11—C10—H10	120.1
C2—C1—C7	120.08 (12)	C9—C10—H10	120.1
C3—C2—C1	120.39 (14)	C12—C11—C10	120.83 (15)
C3—C2—H2	119.8	C12—C11—H11	119.6
C1—C2—H2	119.8	C10—C11—H11	119.6
C4—C3—C2	120.44 (15)	C11—C12—C13	119.22 (16)
C4—C3—H3	119.8	C11—C12—H12	120.4
C2—C3—H3	119.8	C13—C12—H12	120.4
C3—C4—C5	119.99 (14)	C8—C13—C12	121.07 (15)
C3—C4—H4	120.0	C8—C13—H13	119.5
C5—C4—H4	120.0	C12—C13—H13	119.5
C4—C5—C6	120.16 (15)	O2—C14—O1	124.40 (12)
C4—C5—H5	119.9	O2—C14—C8	118.04 (11)
C6—C5—H5	119.9	O1—C14—C8	117.53 (11)
C5—C6—C1	120.36 (13)	O3—C15—H15A	109.5
C5—C6—H6	119.8	O3—C15—H15B	109.5
C1—C6—H6	119.8	H15A—C15—H15B	109.5
N1—C7—N2	118.81 (13)	O3—C15—H15C	109.5
N1—C7—C1	120.25 (11)	H15A—C15—H15C	109.5
N2—C7—C1	120.93 (12)	H15B—C15—H15C	109.5
C9—O3—C15	118.79 (15)
C6—C1—C2—C3	−0.1 (3)	C14—C8—C9—O3	1.6 (2)
C7—C1—C2—C3	−176.85 (16)	C13—C8—C9—C10	0.4 (2)
C1—C2—C3—C4	0.7 (3)	C14—C8—C9—C10	−179.03 (14)
C2—C3—C4—C5	−0.9 (3)	O3—C9—C10—C11	179.31 (17)
C3—C4—C5—C6	0.6 (3)	C8—C9—C10—C11	−0.1 (3)
C4—C5—C6—C1	0.0 (3)	C9—C10—C11—C12	−0.2 (3)
C2—C1—C6—C5	−0.2 (2)	C10—C11—C12—C13	0.1 (3)
C7—C1—C6—C5	176.50 (14)	C9—C8—C13—C12	−0.6 (2)
C6—C1—C7—N1	−173.63 (14)	C14—C8—C13—C12	178.91 (14)
C2—C1—C7—N1	3.1 (2)	C11—C12—C13—C8	0.3 (3)
C6—C1—C7—N2	5.4 (2)	C13—C8—C14—O2	68.85 (18)
C2—C1—C7—N2	−177.93 (15)	C9—C8—C14—O2	−111.69 (16)
C15—O3—C9—C10	−5.5 (3)	C13—C8—C14—O1	−109.51 (16)
C15—O3—C9—C8	173.93 (19)	C9—C8—C14—O1	69.95 (18)
C13—C8—C9—O3	−178.98 (14)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1	0.913 (19)	1.87 (2)	2.7777 (16)	172.4 (17)
N1—H1B···O1i	0.87 (2)	1.97 (2)	2.7926 (15)	155.7 (17)
N2—H2A···O2	0.959 (19)	1.93 (2)	2.8863 (17)	175.4 (16)
N2—H2B···O2ii	0.86 (2)	2.00 (2)	2.8230 (16)	160.3 (18)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1	0.913 (19)	1.87 (2)	2.7777 (16)	172.4 (17)
N1—H1B⋯O1i	0.87 (2)	1.97 (2)	2.7926 (15)	155.7 (17)
N2—H2A⋯O2	0.959 (19)	1.93 (2)	2.8863 (17)	175.4 (16)
N2—H2B⋯O2ii	0.86 (2)	2.00 (2)	2.8230 (16)	160.3 (18)

Symmetry codes: (i) ; (ii) .