4-Meth­oxy­benzamidinium hydrogen oxalate monohydrate

Irrera, S.; Portalone, G.

doi:10.1107/S1600536812046351

Volume 68
Part 12
Pages o3350-o3351
December 2012

Received 6 November 2012
Accepted 9 November 2012
Online 14 November 2012

Key indicators
Single-crystal X-ray study
T = 298 K
Mean (C-C) = 0.003 Å
Disorder in main residue
R = 0.047
wR = 0.110
Data-to-parameter ratio = 10.6
Details

4-Methoxybenzamidinium hydrogen oxalate monohydrate

Simona Irrera ^a and Gustavo Portalone ^a ^*

^aChemistry Department, "Sapienza" University of Rome, P.le A. Moro, 5, I-00185 Rome, Italy
Correspondence e-mail: g.portalone@caspur.it

The title hydrated salt, C₈H₁₁N₂O⁺·C₂HO₄^-·H₂O, was synthesized by a reaction of 4-methoxybenzamidine (4-amidinoanisole) 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 molecule by six distinct N-HO hydrogen bonds. The ion pairs of the asymmetric unit are joined by two N-HO hydrogen bonds into ionic dimers in which the carbonyl O atom of the semi-oxalate anion acts as a bifurcated acceptor, thus generating an R¹₂(6) motif. These subunits are then joined through the remaining N-HO hydrogen bonds to adjacent semi-oxalate anions into linear tetrameric chains running approximately along the b axis. The structure is stabilized by N-HO and O-HO intermolecular hydrogen bonds. The water molecule 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_r = 258.23
Monoclinic, P 2₁ /c
a = 7.1444 (8) Å
b = 9.0428 (7) Å
c = 18.115 (2) Å
= 93.156 (10)°
V = 1168.5 (2) Å³
Z = 4
Mo K radiation
= 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 > 2(I)
R_int = 0.046

Refinement

R[F² > 2(F²)] = 0.047
wR(F²) = 0.110
S = 1.09
2135 reflections
201 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
_max = 0.16 e Å^-3
_min = -0.15 e Å^-3

Table 1
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
N1-H1AO3	0.92 (3)	2.43 (3)	3.180 (3)	138 (2)
N1-H1BO2W	0.92 (2)	2.00 (2)	2.891 (3)	161 (2)
N1-H1AO5ⁱ	0.92 (3)	2.37 (3)	3.096 (2)	135 (2)
N2-H2AO3	0.86 (2)	2.05 (2)	2.869 (2)	159 (2)
N2-H2AO4ⁱⁱ	0.86 (2)	2.34 (2)	2.827 (2)	116.4 (18)
N2-H2BO6ⁱⁱ	0.88 (2)	2.09 (3)	2.932 (2)	159.5 (19)
O4-H4O5ⁱ	1.02 (3)	1.56 (3)	2.5840 (19)	178 (2)
O2W-H21WO5ⁱⁱⁱ	0.85 (2)	2.15 (2)	2.976 (6)	163 (3)
O2W-H22WO6ⁱ	0.88 (2)	1.97 (2)	2.853 (3)	177 (3)
Symmetry codes: (i) $[-x+1, y-{\script{1\over 2}}, -z-{\script{1\over 2}}]$ ; (ii) $[-x+1, y+{\script{1\over 2}}, -z-{\script{1\over 2}}]$ ; (iii) $[x, -y-{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.]$ ); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.]$ ); 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).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: KP2440 ).

References

Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.
Irrera, S., Ortaggi, G. & Portalone, G. (2012). Acta Cryst. C68, o447-o451.
Irrera, S. & Portalone, G. (2012a). Acta Cryst. E68, o3083.
Irrera, S. & Portalone, G. (2012b). Acta Cryst. E68, o3244.
Irrera, S. & Portalone, G. (2012c). Acta Cryst. E68, o3277.
Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.
Portalone, G. (2010). Acta Cryst. C66, o295-o301.
Portalone, G. (2011a). Chem. Centr. J. 5, 51.
Portalone, G. (2011b). Acta Cryst. E67, o3394-o3395.
Portalone, G. (2012). Acta Cryst. E68, o268-o269.
Portalone, G. & Irrera, S. (2011). J. Mol. Struct. 991, 92-96.
Powers, J. C. & Harper, J. W. (1999). Proteinase inhibitors, edited by A. J. Barrett & G. Salvesen, pp. 55-152. Amsterdam: Elsevier.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.

organic compounds