organic compounds
1H-Pyrazol-2-ium hydrogen oxalate
aOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
*Correspondence e-mail: zhurunqiang@163.com
In the title compound, C3H5N2+·C2HO4−, the anions form centrosymmetric dimers through cyclic O—H⋯O hydrogen-bonding associations [graph set R22(10)]. These dimers are then linked through a cyclic R42(10) N—H⋯O hydrogen-bonding association involving two cations and the carboxyl O-atom acceptors of separate anions, giving chain structures extending across the (111) plane.
Related literature
For general background to ferroelectric organic frameworks, see: Fu et al. (2009); Ye et al. (2006); Zhang et al. (2008, 2010). For graph-set analysis, see: Etter et al. (1990).
Experimental
Crystal data
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Refinement
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Data collection: CrystalClear (Rigaku, 2005); cell CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536812023136/zs2209sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812023136/zs2209Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812023136/zs2209Isup3.cml
A mixture of pyrazole (0.68 g, 10 mmol) and oxalic acid (0.95 g, 10 mmol) in water was stirred for several days at ambient temperature. Colourless crystal plates of the title compound suitable for X-ray analysis were obtained.
Hydrogen atom positions were calculated and allowed to ride on their parent atoms with aromatic C—H = 0.93 Å, N—H = 0.86 Å and O—H = 0.82 Å, and with Uiso(H) = 1.2Ueq(C or N) and Uiso(H) = 1.5Ueq(O).
Data collection: CrystalClear (Rigaku, 2005); cell
CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C3H5N2+·C2HO4− | Z = 2 |
Mr = 158.12 | F(000) = 164 |
Triclinic, P1 | Dx = 1.563 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 3.7286 (7) Å | Cell parameters from 1527 reflections |
b = 9.836 (2) Å | θ = 2.4–27.5° |
c = 10.487 (2) Å | µ = 0.14 mm−1 |
α = 117.35 (3)° | T = 293 K |
β = 97.01 (3)° | Sheet, colourless |
γ = 93.65 (3)° | 0.26 × 0.22 × 0.14 mm |
V = 335.92 (14) Å3 |
Rigaku SCXmini CCD diffractometer | 1527 independent reflections |
Radiation source: fine-focus sealed tube | 702 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.063 |
CCD_Profile_fitting scans | θmax = 27.5°, θmin = 3.9° |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005) | h = −4→4 |
Tmin = 0.965, Tmax = 0.993 | k = −12→12 |
3484 measured reflections | l = −13→13 |
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)] = 0.095 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.285 | H-atom parameters constrained |
S = 1.07 | w = 1/[σ2(Fo2) + (0.1349P)2 + 0.0952P] where P = (Fo2 + 2Fc2)/3 |
1527 reflections | (Δ/σ)max < 0.001 |
101 parameters | Δρmax = 0.48 e Å−3 |
0 restraints | Δρmin = −0.29 e Å−3 |
C3H5N2+·C2HO4− | γ = 93.65 (3)° |
Mr = 158.12 | V = 335.92 (14) Å3 |
Triclinic, P1 | Z = 2 |
a = 3.7286 (7) Å | Mo Kα radiation |
b = 9.836 (2) Å | µ = 0.14 mm−1 |
c = 10.487 (2) Å | T = 293 K |
α = 117.35 (3)° | 0.26 × 0.22 × 0.14 mm |
β = 97.01 (3)° |
Rigaku SCXmini CCD diffractometer | 1527 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005) | 702 reflections with I > 2σ(I) |
Tmin = 0.965, Tmax = 0.993 | Rint = 0.063 |
3484 measured reflections |
R[F2 > 2σ(F2)] = 0.095 | 0 restraints |
wR(F2) = 0.285 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.48 e Å−3 |
1527 reflections | Δρmin = −0.29 e Å−3 |
101 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > 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 | ||
N1 | 1.0872 (11) | 0.0136 (5) | 0.3057 (4) | 0.0416 (11) | |
H1A | 1.1595 | −0.0585 | 0.3230 | 0.050* | |
N2 | 1.1523 (11) | 0.1643 (5) | 0.3992 (4) | 0.0412 (11) | |
H2A | 1.2729 | 0.2054 | 0.4865 | 0.049* | |
C1 | 0.9992 (15) | 0.2395 (6) | 0.3352 (6) | 0.0493 (15) | |
H1 | 1.0047 | 0.3461 | 0.3773 | 0.059* | |
C2 | 0.8307 (15) | 0.1355 (7) | 0.1967 (6) | 0.0505 (15) | |
H2 | 0.7020 | 0.1567 | 0.1277 | 0.061* | |
C3 | 0.8931 (15) | −0.0076 (7) | 0.1818 (6) | 0.0477 (14) | |
H3 | 0.8131 | −0.1021 | 0.0993 | 0.057* | |
O1 | 0.3997 (10) | 0.8001 (4) | 0.3600 (3) | 0.0475 (10) | |
O2 | 0.6353 (11) | 0.5351 (4) | 0.3418 (4) | 0.0577 (12) | |
O3 | 0.0807 (11) | 0.6588 (4) | 0.1355 (4) | 0.0581 (11) | |
O4 | 0.3270 (11) | 0.4012 (4) | 0.1179 (4) | 0.0554 (11) | |
H4 | 0.1905 | 0.4187 | 0.0612 | 0.083* | |
C4 | 0.2907 (14) | 0.6762 (6) | 0.2446 (5) | 0.0402 (13) | |
C5 | 0.4374 (14) | 0.5304 (6) | 0.2400 (5) | 0.0425 (13) |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.049 (3) | 0.033 (2) | 0.041 (2) | 0.0045 (19) | −0.0029 (19) | 0.019 (2) |
N2 | 0.048 (3) | 0.034 (2) | 0.031 (2) | 0.005 (2) | −0.0023 (19) | 0.0087 (19) |
C1 | 0.053 (3) | 0.045 (3) | 0.056 (4) | 0.011 (3) | 0.006 (3) | 0.029 (3) |
C2 | 0.053 (4) | 0.052 (4) | 0.048 (3) | 0.010 (3) | −0.002 (3) | 0.027 (3) |
C3 | 0.047 (3) | 0.042 (3) | 0.041 (3) | 0.004 (2) | −0.006 (2) | 0.011 (3) |
O1 | 0.062 (2) | 0.033 (2) | 0.037 (2) | 0.0087 (17) | −0.0074 (17) | 0.0110 (18) |
O2 | 0.076 (3) | 0.043 (2) | 0.045 (2) | 0.0122 (19) | −0.0127 (19) | 0.018 (2) |
O3 | 0.077 (3) | 0.042 (2) | 0.044 (2) | 0.0123 (19) | −0.0126 (19) | 0.0155 (19) |
O4 | 0.075 (3) | 0.032 (2) | 0.045 (2) | 0.0098 (19) | −0.0082 (19) | 0.0113 (19) |
C4 | 0.047 (3) | 0.032 (3) | 0.035 (3) | 0.005 (2) | 0.005 (2) | 0.011 (2) |
C5 | 0.050 (3) | 0.033 (3) | 0.039 (3) | 0.003 (2) | 0.004 (3) | 0.013 (3) |
N1—C3 | 1.325 (6) | C2—H2 | 0.9300 |
N1—N2 | 1.333 (5) | C3—H3 | 0.9300 |
N1—H1A | 0.8601 | O1—C4 | 1.256 (6) |
N2—C1 | 1.319 (6) | O2—C5 | 1.202 (6) |
N2—H2A | 0.8600 | O3—C4 | 1.239 (6) |
C1—C2 | 1.372 (7) | O4—C5 | 1.317 (6) |
C1—H1 | 0.9300 | O4—H4 | 0.8200 |
C2—C3 | 1.380 (8) | C4—C5 | 1.549 (7) |
C3—N1—N2 | 109.3 (4) | C3—C2—H2 | 127.4 |
C3—N1—H1A | 125.3 | N1—C3—C2 | 108.0 (5) |
N2—N1—H1A | 125.4 | N1—C3—H3 | 126.0 |
C1—N2—N1 | 108.4 (4) | C2—C3—H3 | 126.0 |
C1—N2—H2A | 125.8 | C5—O4—H4 | 109.5 |
N1—N2—H2A | 125.8 | O3—C4—O1 | 127.0 (5) |
N2—C1—C2 | 109.1 (5) | O3—C4—C5 | 117.3 (4) |
N2—C1—H1 | 125.4 | O1—C4—C5 | 115.7 (4) |
C2—C1—H1 | 125.4 | O2—C5—O4 | 122.4 (5) |
C1—C2—C3 | 105.2 (5) | O2—C5—C4 | 122.1 (5) |
C1—C2—H2 | 127.4 | O4—C5—C4 | 115.4 (4) |
C3—N1—N2—C1 | 0.1 (6) | O3—C4—C5—O2 | −178.2 (5) |
N1—N2—C1—C2 | 0.0 (6) | O1—C4—C5—O2 | 1.9 (8) |
N2—C1—C2—C3 | 0.0 (6) | O3—C4—C5—O4 | 1.0 (7) |
N2—N1—C3—C2 | −0.1 (6) | O1—C4—C5—O4 | −178.9 (4) |
C1—C2—C3—N1 | 0.1 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1i | 0.86 | 1.86 | 2.709 (5) | 170 |
N2—H2A···O1ii | 0.86 | 1.92 | 2.715 (5) | 153 |
O4—H4···O3iii | 0.82 | 1.95 | 2.679 (5) | 147 |
Symmetry codes: (i) x+1, y−1, z; (ii) −x+2, −y+1, −z+1; (iii) −x, −y+1, −z. |
Experimental details
Crystal data | |
Chemical formula | C3H5N2+·C2HO4− |
Mr | 158.12 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 3.7286 (7), 9.836 (2), 10.487 (2) |
α, β, γ (°) | 117.35 (3), 97.01 (3), 93.65 (3) |
V (Å3) | 335.92 (14) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.14 |
Crystal size (mm) | 0.26 × 0.22 × 0.14 |
Data collection | |
Diffractometer | Rigaku SCXmini CCD diffractometer |
Absorption correction | Multi-scan (CrystalClear; Rigaku, 2005) |
Tmin, Tmax | 0.965, 0.993 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3484, 1527, 702 |
Rint | 0.063 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.095, 0.285, 1.07 |
No. of reflections | 1527 |
No. of parameters | 101 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.48, −0.29 |
Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O1i | 0.86 | 1.86 | 2.709 (5) | 169.6 |
N2—H2A···O1ii | 0.86 | 1.92 | 2.715 (5) | 152.7 |
O4—H4···O3iii | 0.82 | 1.95 | 2.679 (5) | 147.4 |
Symmetry codes: (i) x+1, y−1, z; (ii) −x+2, −y+1, −z+1; (iii) −x, −y+1, −z. |
Acknowledgements
This work was supported by Southeast University.
References
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As a contribution to a search for new ferroelectric materials (Fu et al., 2009; Ye et al., 2006; Zhang et al., 2008, 2010), we have synthesized the title salt, C3H5N2+. C2HO4- from a 1:1 stoichiometric reaction of pyrazole with oxalic acid and the structure is reported here.
In the structure of the title compound (Fig.1) the molecules are organized in a one-dimensional chain structure involving both inter-anionic and cation–anion hydrogen-bonding associations (Table 1). The anions form centrosymmetric dimers through cyclic O—H···O hydrogen-bonding associations [graph set R22(10) (Etter et al., 1990)]. These dimers are then linked through a cyclic R24(10) N—H···O hydrogen-bonding association involving two cations and the carboxyl O-atom acceptors of separate anions, giving one-dimensional chain structures extending across the (111) plane (Fig. 2).