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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 [sigma](C-C) = 0.003 Å
Disorder in main residue
R = 0.047
wR = 0.110
Data-to-parameter ratio = 10.6
Details
Open access

4-Methoxybenzamidinium hydrogen oxalate monohydrate

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-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 R12(6) motif. These subunits are then joined through the remaining N-H...O hydrogen bonds to adjacent semi-oxalate anions into linear tetrameric chains running approximately along the b axis. The structure is stabilized by N-H...O and O-H...O 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[Powers, J. C. & Harper, J. W. (1999). Proteinase inhibitors, edited by A. J. Barrett & G. Salvesen, pp. 55-152. Amsterdam: Elsevier.]). For structural analysis of proton-transfer adducts containing molecules of biological interest, see: Portalone, (2011a[Portalone, G. (2011a). Chem. Centr. J. 5, 51.]); Portalone & Irrera (2011[Portalone, G. & Irrera, S. (2011). J. Mol. Struct. 991, 92-96.]). For supramolecular association in proton-transfer adducts containing benzamidinium cations, see; Portalone (2010[Portalone, G. (2010). Acta Cryst. C66, o295-o301.], 2011b[Portalone, G. (2011b). Acta Cryst. E67, o3394-o3395.], 2012[Portalone, G. (2012). Acta Cryst. E68, o268-o269.]); Irrera et al. (2012[Irrera, S., Ortaggi, G. & Portalone, G. (2012). Acta Cryst. C68, o447-o451.]); Irrera & Portalone (2012a[Irrera, S. & Portalone, G. (2012a). Acta Cryst. E68, o3083.],b[Irrera, S. & Portalone, G. (2012b). Acta Cryst. E68, o3244.],c[Irrera, S. & Portalone, G. (2012c). Acta Cryst. E68, o3277.]). For hydrogen-bond motifs, see Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C8H11N2O+·C2HO4-·H2O

  • Mr = 258.23

  • Monoclinic, P 21 /c

  • a = 7.1444 (8) Å

  • b = 9.0428 (7) Å

  • c = 18.115 (2) Å

  • [beta] = 93.156 (10)°

  • V = 1168.5 (2) Å3

  • Z = 4

  • Mo K[alpha] radiation

  • [mu] = 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[Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.]) Tmin = 0.978, Tmax = 0.989

  • 15203 measured reflections

  • 2135 independent reflections

  • 1693 reflections with I > 2[sigma](I)

  • Rint = 0.046

Refinement
  • R[F2 > 2[sigma](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

  • [Delta][rho]max = 0.16 e Å-3

  • [Delta][rho]min = -0.15 e Å-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) [-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[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.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]); software used to prepare material for publication: WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]).


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.  [ISI] [CrossRef] [ChemPort] [details]
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.  [CrossRef] [ChemPort] [ISI]
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.  [ISI] [CrossRef] [ChemPort] [details]
Irrera, S., Ortaggi, G. & Portalone, G. (2012). Acta Cryst. C68, o447-o451.  [CrossRef] [details]
Irrera, S. & Portalone, G. (2012a). Acta Cryst. E68, o3083.  [CSD] [CrossRef] [details]
Irrera, S. & Portalone, G. (2012b). Acta Cryst. E68, o3244.  [CSD] [CrossRef] [details]
Irrera, S. & Portalone, G. (2012c). Acta Cryst. E68, o3277.  [CrossRef] [details]
Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England.
Portalone, G. (2010). Acta Cryst. C66, o295-o301.  [CSD] [CrossRef] [details]
Portalone, G. (2011a). Chem. Centr. J. 5, 51.  [CSD] [CrossRef]
Portalone, G. (2011b). Acta Cryst. E67, o3394-o3395.  [CSD] [CrossRef] [details]
Portalone, G. (2012). Acta Cryst. E68, o268-o269.  [CSD] [CrossRef] [details]
Portalone, G. & Irrera, S. (2011). J. Mol. Struct. 991, 92-96.  [ISI] [CSD] [CrossRef] [ChemPort]
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.  [CrossRef] [details]


Acta Cryst (2012). E68, o3350-o3351   [ doi:10.1107/S1600536812046351 ]

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