4-Meth-oxy-benzamidinium hydrogen oxalate monohydrate.

The title hydrated salt, C8H11N2O(+)·C2HO4(-)·H2O, was synthesized by a reaction of 4-meth-oxy-benzamidine (4-amidino-anisole) and oxalic acid in water solution. In the cation, the amidinium group forms a dihedral angle of 15.60 (6)° with the mean plane of the benzene ring. In the crystal, each amidinium unit is bound to three acetate anions and one water mol-ecule by six distinct N-H⋯O hydrogen bonds. The ion pairs of the asymmetric unit are joined by two N-H⋯O hydrogen bonds into ionic dimers in which the carbonyl O atom of the semi-oxalate anion acts as a bifurcated acceptor, thus generating an R(1)2(6) motif. These subunits are then joined through the remaining N-H⋯O hydrogen bonds to adjacent semi-oxalate anions into linear tetra-meric chains running approximately along the b axis. The structure is stabilized by N-H⋯O and O-H⋯O inter-molecular hydrogen bonds. The water mol-ecule plays an important role in the cohesion and the stability of the crystal structure being involved in three hydrogen bonds connecting two semi-oxalate anions as donor and a benzamidinium cation as acceptor.

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: Portalone, (2011a ▶); Portalone & Irrera (2011 ▶). For supra­molecular association in proton-transfer adducts containing benzamidinium cations, see; Portalone (2010 ▶, 2011b ▶, 2012 ▶); Irrera et al. (2012 ▶); Irrera & Portalone (2012a ▶,b ▶,c ▶). For hydrogen-bond motifs, see Bernstein et al. (1995 ▶).

Experimental

Crystal data

C8H11N2O+·C2HO4 −·H2O

M = 258.23

Monoclinic,

a = 7.1444 (8) Å

b = 9.0428 (7) Å

c = 18.115 (2) Å

β = 93.156 (10)°

V = 1168.5 (2) Å3

Z = 4

Mo Kα radiation

μ = 0.12 mm−1

T = 298 K

0.18 × 0.12 × 0.09 mm

Data collection

Oxford Diffraction Xcalibur S CCD diffractometer

Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T min = 0.978, T max = 0.989

15203 measured reflections

2135 independent reflections

1693 reflections with I > 2σ(I)

R int = 0.046

Refinement

R[F 2 > 2σ(F 2)] = 0.047

wR(F 2) = 0.110

S = 1.09

2135 reflections

201 parameters

2 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.16 e Å−3

Δρmin = −0.15 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 ▶); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2006 ▶); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Click here for additional data file.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812046351/kp2440sup1.cif

Click here for additional data file.

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812046351/kp2440Isup2.hkl

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

C8H11N2O+·C2HO4−·H2O	F(000) = 544
Mr = 258.23	Dx = 1.468 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybc	Cell parameters from 4235 reflections
a = 7.1444 (8) Å	θ = 3.0–29.1°
b = 9.0428 (7) Å	µ = 0.12 mm−1
c = 18.115 (2) Å	T = 298 K
β = 93.156 (10)°	Tablets, colourless
V = 1168.5 (2) Å3	0.18 × 0.12 × 0.09 mm
Z = 4

Oxford Diffraction Xcalibur S CCD diffractometer	2135 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1693 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.046
Detector resolution: 16.0696 pixels mm-1	θmax = 25.4°, θmin = 3.2°
ω and φ scans	h = −8→8
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −10→10
Tmin = 0.978, Tmax = 0.989	l = −21→21
15203 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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.110	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	w = 1/[σ2(Fo2) + (0.0502P)2 + 0.2028P] where P = (Fo2 + 2Fc2)/3
2135 reflections	(Δ/σ)max < 0.001
201 parameters	Δρmax = 0.16 e Å−3
2 restraints	Δρmin = −0.15 e Å−3

Experimental. Absorption correction: CrysAlisPro, Agilent Technologies, Version 1.171.35.19 (release 27-10-2011 CrysAlis171 .NET) (compiled Oct 27 2011,15:02:11) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

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	Occ. (<1)
O1	0.8980 (2)	0.07501 (16)	0.24710 (8)	0.0511 (4)
N1	0.7104 (3)	−0.2554 (2)	−0.06019 (12)	0.0484 (5)
H1A	0.671 (4)	−0.287 (3)	−0.1070 (16)	0.084 (9)*
H1B	0.728 (3)	−0.326 (3)	−0.0238 (13)	0.060 (7)*
N2	0.6975 (3)	−0.0163 (2)	−0.09613 (11)	0.0439 (5)
H2A	0.668 (3)	−0.043 (2)	−0.1409 (14)	0.055 (7)*
H2B	0.702 (3)	0.080 (3)	−0.0883 (12)	0.053 (7)*
C1	0.7801 (2)	−0.0672 (2)	0.03205 (10)	0.0327 (4)
C2	0.8530 (3)	−0.1659 (2)	0.08440 (11)	0.0420 (5)
H2	0.8730	−0.2635	0.0707	0.050*
C3	0.8970 (3)	−0.1231 (2)	0.15668 (11)	0.0414 (5)
H3	0.9472	−0.1908	0.1910	0.050*
C4	0.8654 (3)	0.0217 (2)	0.17730 (11)	0.0371 (5)
C5	0.7954 (3)	0.1222 (2)	0.12537 (11)	0.0440 (5)
H5	0.7761	0.2199	0.1390	0.053*
C6	0.7543 (3)	0.0788 (2)	0.05387 (11)	0.0395 (5)
H6	0.7085	0.1478	0.0194	0.047*
C7	0.7288 (2)	−0.1139 (2)	−0.04408 (10)	0.0346 (5)
C8	0.9800 (3)	−0.0223 (3)	0.30183 (12)	0.0542 (6)
H8A	0.9075 (15)	−0.1129 (14)	0.3028 (6)	0.081*
H8B	0.981 (2)	0.0250 (9)	0.3499 (7)	0.081*
H8C	1.1076 (19)	−0.0452 (14)	0.2900 (5)	0.081*
O3	0.6035 (2)	−0.17989 (15)	−0.22870 (8)	0.0506 (4)
O4	0.4130 (2)	−0.35402 (14)	−0.27537 (8)	0.0448 (4)
H4	0.454 (4)	−0.412 (3)	−0.2291 (15)	0.086 (8)*
O5	0.4872 (2)	0.00180 (14)	−0.34351 (8)	0.0478 (4)
O6	0.3608 (2)	−0.19541 (15)	−0.39997 (8)	0.0517 (4)
C9	0.4936 (3)	−0.22516 (19)	−0.27658 (11)	0.0354 (5)
C10	0.4403 (3)	−0.1325 (2)	−0.34652 (11)	0.0383 (5)
O2W	0.7296 (9)	−0.5215 (3)	0.02842 (17)	0.0531 (13)	0.85 (2)
H21W	0.646 (3)	−0.530 (3)	0.0600 (14)	0.080*
H22W	0.699 (4)	−0.578 (3)	−0.0102 (12)	0.080*
O21W	0.845 (10)	−0.520 (2)	0.008 (2)	0.101 (17)	0.15 (2)

	U11	U22	U33	U12	U13	U23
O1	0.0703 (10)	0.0445 (8)	0.0369 (8)	0.0073 (7)	−0.0118 (7)	−0.0061 (7)
N1	0.0728 (13)	0.0325 (10)	0.0385 (11)	−0.0018 (9)	−0.0083 (10)	−0.0023 (9)
N2	0.0607 (12)	0.0371 (11)	0.0328 (11)	−0.0035 (8)	−0.0074 (9)	0.0024 (8)
C1	0.0334 (10)	0.0303 (10)	0.0341 (11)	−0.0011 (8)	0.0007 (8)	−0.0002 (8)
C2	0.0576 (13)	0.0273 (10)	0.0406 (12)	0.0026 (9)	−0.0034 (10)	−0.0015 (9)
C3	0.0513 (13)	0.0332 (10)	0.0386 (12)	0.0015 (9)	−0.0080 (10)	0.0052 (9)
C4	0.0373 (11)	0.0383 (11)	0.0353 (11)	−0.0010 (8)	−0.0021 (8)	−0.0038 (9)
C5	0.0572 (13)	0.0292 (10)	0.0449 (13)	0.0061 (9)	−0.0045 (10)	−0.0041 (9)
C6	0.0494 (12)	0.0315 (10)	0.0370 (11)	0.0048 (9)	−0.0043 (9)	0.0042 (9)
C7	0.0354 (11)	0.0333 (10)	0.0348 (11)	−0.0016 (8)	−0.0007 (8)	0.0009 (9)
C8	0.0646 (15)	0.0563 (14)	0.0402 (13)	0.0030 (11)	−0.0105 (11)	0.0007 (11)
O3	0.0705 (10)	0.0363 (8)	0.0427 (9)	−0.0050 (7)	−0.0184 (8)	−0.0008 (6)
O4	0.0650 (10)	0.0293 (7)	0.0386 (9)	−0.0066 (6)	−0.0096 (7)	0.0046 (6)
O5	0.0765 (11)	0.0278 (7)	0.0379 (8)	−0.0054 (7)	−0.0081 (7)	0.0019 (6)
O6	0.0857 (11)	0.0329 (8)	0.0343 (9)	−0.0044 (7)	−0.0164 (8)	−0.0001 (6)
C9	0.0458 (12)	0.0257 (9)	0.0345 (11)	0.0045 (8)	−0.0006 (9)	−0.0040 (8)
C10	0.0511 (12)	0.0289 (10)	0.0346 (11)	0.0007 (9)	−0.0014 (9)	−0.0016 (8)
O2W	0.074 (3)	0.0401 (12)	0.0453 (15)	−0.0055 (13)	0.0009 (14)	−0.0065 (9)
O21W	0.15 (4)	0.067 (10)	0.078 (16)	0.022 (14)	−0.04 (2)	−0.021 (9)

O1—C4	1.361 (2)	C5—C6	1.370 (3)
O1—C8	1.427 (2)	C5—H5	0.9300
N1—C7	1.317 (3)	C6—H6	0.9300
N1—H1A	0.92 (3)	C8—H8A	0.9696
N1—H1B	0.92 (2)	C8—H8B	0.9697
N2—C7	1.302 (2)	C8—H8C	0.9696
N2—H2A	0.86 (2)	O3—C9	1.209 (2)
N2—H2B	0.88 (2)	O4—C9	1.300 (2)
C1—C2	1.383 (3)	O4—H4	1.02 (3)
C1—C6	1.393 (3)	O5—C10	1.260 (2)
C1—C7	1.470 (3)	O6—C10	1.234 (2)
C2—C3	1.385 (3)	C9—C10	1.549 (3)
C2—H2	0.9300	O2W—O21W	0.92 (8)
C3—C4	1.383 (3)	O2W—H21W	0.854 (17)
C3—H3	0.9300	O2W—H22W	0.883 (17)
C4—C5	1.382 (3)	O21W—H22W	1.20 (6)
C4—O1—C8	118.00 (16)	C5—C6—H6	119.5
C7—N1—H1A	121.5 (18)	C1—C6—H6	119.5
C7—N1—H1B	120.6 (14)	N2—C7—N1	119.1 (2)
H1A—N1—H1B	118 (2)	N2—C7—C1	120.56 (18)
C7—N2—H2A	121.0 (15)	N1—C7—C1	120.28 (18)
C7—N2—H2B	123.3 (14)	O1—C8—H8A	109.5
H2A—N2—H2B	116 (2)	O1—C8—H8B	109.5
C2—C1—C6	117.90 (17)	H8A—C8—H8B	109.5
C2—C1—C7	121.50 (17)	O1—C8—H8C	109.5
C6—C1—C7	120.59 (17)	H8A—C8—H8C	109.5
C1—C2—C3	121.65 (18)	H8B—C8—H8C	109.5
C1—C2—H2	119.2	C9—O4—H4	111.6 (15)
C3—C2—H2	119.2	O3—C9—O4	124.20 (18)
C4—C3—C2	119.22 (18)	O3—C9—C10	121.61 (17)
C4—C3—H3	120.4	O4—C9—C10	114.18 (17)
C2—C3—H3	120.4	O6—C10—O5	126.03 (18)
O1—C4—C5	115.88 (17)	O6—C10—C9	118.28 (16)
O1—C4—C3	124.32 (18)	O5—C10—C9	115.68 (17)
C5—C4—C3	119.80 (18)	O21W—O2W—H21W	161 (2)
C6—C5—C4	120.39 (18)	O21W—O2W—H22W	83 (2)
C6—C5—H5	119.8	H21W—O2W—H22W	109 (3)
C4—C5—H5	119.8	O2W—O21W—H22W	47 (3)
C5—C6—C1	121.01 (18)
C6—C1—C2—C3	0.9 (3)	C2—C1—C6—C5	−1.6 (3)
C7—C1—C2—C3	−178.30 (18)	C7—C1—C6—C5	177.63 (18)
C1—C2—C3—C4	0.7 (3)	C2—C1—C7—N2	−165.77 (19)
C8—O1—C4—C5	−176.59 (18)	C6—C1—C7—N2	15.0 (3)
C8—O1—C4—C3	3.7 (3)	C2—C1—C7—N1	15.5 (3)
C2—C3—C4—O1	177.98 (18)	C6—C1—C7—N1	−163.68 (19)
C2—C3—C4—C5	−1.7 (3)	O3—C9—C10—O6	164.7 (2)
O1—C4—C5—C6	−178.67 (17)	O4—C9—C10—O6	−14.1 (3)
C3—C4—C5—C6	1.1 (3)	O3—C9—C10—O5	−13.9 (3)
C4—C5—C6—C1	0.6 (3)	O4—C9—C10—O5	167.33 (17)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O3	0.92 (3)	2.43 (3)	3.180 (3)	138 (2)
N1—H1B···O2W	0.92 (2)	2.00 (2)	2.891 (3)	161 (2)
N1—H1A···O5i	0.92 (3)	2.37 (3)	3.096 (2)	135 (2)
N2—H2A···O3	0.86 (2)	2.05 (2)	2.869 (2)	159 (2)
N2—H2A···O4ii	0.86 (2)	2.34 (2)	2.827 (2)	116.4 (18)
N2—H2B···O6ii	0.88 (2)	2.09 (3)	2.932 (2)	159.5 (19)
O4—H4···O5i	1.02 (3)	1.56 (3)	2.5840 (19)	178 (2)
O2W—H21W···O5iii	0.85 (2)	2.15 (2)	2.976 (6)	163 (3)
O2W—H22W···O6i	0.88 (2)	1.97 (2)	2.853 (3)	177 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O3	0.92 (3)	2.43 (3)	3.180 (3)	138 (2)
N1—H1B⋯O2W	0.92 (2)	2.00 (2)	2.891 (3)	161 (2)
N1—H1A⋯O5i	0.92 (3)	2.37 (3)	3.096 (2)	135 (2)
N2—H2A⋯O3	0.86 (2)	2.05 (2)	2.869 (2)	159 (2)
N2—H2A⋯O4ii	0.86 (2)	2.34 (2)	2.827 (2)	116.4 (18)
N2—H2B⋯O6ii	0.88 (2)	2.09 (3)	2.932 (2)	159.5 (19)
O4—H4⋯O5i	1.02 (3)	1.56 (3)	2.5840 (19)	178 (2)
O2W—H21W⋯O5iii	0.85 (2)	2.15 (2)	2.976 (6)	163 (3)
O2W—H22W⋯O6i	0.88 (2)	1.97 (2)	2.853 (3)	177 (3)

Symmetry codes: (i) ; (ii) ; (iii) .