organic compounds
1-Methylpiperazine-1,4-dium bis(hydrogen oxalate)
aLaboratoire de Chimie des Matériaux, Faculté des Sciences de Bizerte, 7021 Zarzouna Bizerte, Tunisia
*Correspondence e-mail: essidmanel@voila.fr
In the 5H14N22+·2HC2O4−, the two crystallographically independent hydrogen oxalate anions are linked by strong intermolecular O—H⋯O hydrogen bonds, forming two independent corrugated chains parallel to the b axis. These chains are further connected by N—H⋯O and C—H⋯O hydrogen bonds originating from the organic cations, forming a three-dimensional network. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position.
of the title compound, CCCDC reference: 987380
Related literature
For the biological activity of piperazines, see: Conrado et al. (2008); Brockunier et al. (2004); Bogatcheva et al. (2006). For related structures, see: Essid et al. (2013); Dutkiewicz et al. (2011); Vaidhyanathan et al. (2002); Ejsmont & Zaleski (2006). For puckering parameters, see: Cremer & Pople (1975).
Experimental
Crystal data
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Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 2012).
Supporting information
CCDC reference: 987380
10.1107/S1600536814003559/zl2578sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536814003559/zl2578Isup2.hkl
An aqueous solution containing 2 mmol of H2C2O4 in 20 ml of water was added to 1 mmol of 1-methylpiperazine in 10 ml of ethanol. The obtained solution was stirred at 333 K. When the solution became homogeneous it was cooled slowly and kept at room temperature. After several days, transparent colourless crystals formed. Crystals of the title compound, which remained stable under normal conditions of temperature and humidity, were isolated and subjected to X-ray
M.p. 260°C. Main IR bands (KBr disc, cm-1): (vs = very strong; s = strong; w = weak) 3025 w, 1619 s, 1470 s, 1410 s, 1356 vs, 1269 vs, 1203 w, 1050 vs, 1022 s, 985 s, 713 s.All H atoms were located in a difference map. Nevertheless, they were geometrically placed and refined using a riding model, with C—H = 0.96 Å (methyl) or 0.97 Å (methylene), N—H = 0.90 Å or 0.91 Å and O—H = 0.82 Å with Uiso(H) = 1.2Ueq(C or N) or 1.5Ueq(O).
Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell
CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 2012).Fig. 1. An ORTEP view of (I) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 45% probability level. H atoms are represented as small spheres of arbitrary radii. | |
Fig. 2. Projection of the corrugated hydrogen oxalate chains along the a axis. | |
Fig. 3. Projection of (I) along the b axis. The H-atoms not involved in H-bonding are omitted. |
C5H14N22+·2C2HO4− | F(000) = 1184 |
Mr = 280.24 | Dx = 1.585 Mg m−3 |
Monoclinic, C2/c | Ag Kα radiation, λ = 0.56083 Å |
Hall symbol: -C 2yc | Cell parameters from 25 reflections |
a = 15.649 (2) Å | θ = 9–11° |
b = 5.681 (3) Å | µ = 0.08 mm−1 |
c = 27.230 (2) Å | T = 293 K |
β = 104.05 (2)° | Prism, colourless |
V = 2348.4 (13) Å3 | 0.35 × 0.25 × 0.15 mm |
Z = 8 |
Enraf–Nonius CAD-4 diffractometer | Rint = 0.027 |
Radiation source: fine-focus sealed tube | θmax = 28.0°, θmin = 2.1° |
Graphite monochromator | h = −26→25 |
non–profiled ω scans | k = −2→9 |
7879 measured reflections | l = −1→45 |
5758 independent reflections | 2 standard reflections every 120 min |
3621 reflections with I > 2σ(I) | intensity decay: none |
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)] = 0.052 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.162 | H-atom parameters constrained |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0887P)2 + 0.6525P] where P = (Fo2 + 2Fc2)/3 |
5757 reflections | (Δ/σ)max = 0.006 |
175 parameters | Δρmax = 0.41 e Å−3 |
0 restraints | Δρmin = −0.40 e Å−3 |
C5H14N22+·2C2HO4− | V = 2348.4 (13) Å3 |
Mr = 280.24 | Z = 8 |
Monoclinic, C2/c | Ag Kα radiation, λ = 0.56083 Å |
a = 15.649 (2) Å | µ = 0.08 mm−1 |
b = 5.681 (3) Å | T = 293 K |
c = 27.230 (2) Å | 0.35 × 0.25 × 0.15 mm |
β = 104.05 (2)° |
Enraf–Nonius CAD-4 diffractometer | Rint = 0.027 |
7879 measured reflections | 2 standard reflections every 120 min |
5758 independent reflections | intensity decay: none |
3621 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.052 | 0 restraints |
wR(F2) = 0.162 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.41 e Å−3 |
5757 reflections | Δρmin = −0.40 e Å−3 |
175 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 | ||
O5 | 0.26348 (5) | 0.43588 (15) | 0.19137 (4) | 0.02858 (19) | |
H5 | 0.2892 | 0.3099 | 0.1980 | 0.043* | |
O6 | 0.39346 (6) | 0.58784 (19) | 0.23195 (5) | 0.0436 (3) | |
O7 | 0.19490 (5) | 0.86264 (16) | 0.17619 (4) | 0.02856 (19) | |
O8 | 0.32494 (5) | 1.02361 (15) | 0.21317 (4) | 0.02746 (18) | |
C8 | 0.27389 (6) | 0.85255 (19) | 0.19799 (4) | 0.02018 (18) | |
C9 | 0.31747 (7) | 0.60820 (19) | 0.20900 (4) | 0.02266 (19) | |
O1 | 0.12751 (6) | −0.01254 (18) | 0.05548 (4) | 0.0373 (2) | |
O2 | 0.26291 (6) | 0.13819 (16) | 0.08184 (4) | 0.0348 (2) | |
H2 | 0.2366 | 0.2642 | 0.0780 | 0.052* | |
O3 | 0.20184 (6) | −0.45041 (16) | 0.06515 (4) | 0.0331 (2) | |
O4 | 0.33311 (5) | −0.28288 (16) | 0.09557 (4) | 0.0334 (2) | |
C6 | 0.20627 (7) | −0.03411 (19) | 0.07029 (5) | 0.0231 (2) | |
C7 | 0.25214 (7) | −0.27840 (19) | 0.07768 (4) | 0.02206 (19) | |
N1 | 0.45019 (6) | 0.07065 (18) | 0.09040 (4) | 0.02256 (18) | |
H1 | 0.4022 | −0.0041 | 0.0963 | 0.027* | |
N2 | 0.57669 (6) | 0.01455 (19) | 0.18579 (4) | 0.0264 (2) | |
H2C | 0.5933 | −0.0381 | 0.2179 | 0.032* | |
H2D | 0.6228 | 0.0897 | 0.1786 | 0.032* | |
C1 | 0.42704 (10) | 0.1657 (3) | 0.03769 (5) | 0.0418 (3) | |
H1A | 0.3819 | 0.2830 | 0.0347 | 0.063* | |
H1B | 0.4060 | 0.0401 | 0.0143 | 0.063* | |
H1C | 0.4783 | 0.2351 | 0.0302 | 0.063* | |
C2 | 0.47453 (7) | 0.2672 (2) | 0.12710 (5) | 0.0261 (2) | |
H2A | 0.4245 | 0.3722 | 0.1237 | 0.031* | |
H2B | 0.5225 | 0.3562 | 0.1193 | 0.031* | |
C3 | 0.50225 (7) | 0.1799 (2) | 0.18088 (5) | 0.0270 (2) | |
H3A | 0.5198 | 0.3118 | 0.2037 | 0.032* | |
H3B | 0.4532 | 0.1011 | 0.1899 | 0.032* | |
C4 | 0.55098 (8) | −0.1872 (2) | 0.15092 (5) | 0.0298 (2) | |
H4A | 0.5024 | −0.2710 | 0.1593 | 0.036* | |
H4B | 0.6002 | −0.2952 | 0.1547 | 0.036* | |
C5 | 0.52395 (7) | −0.1014 (2) | 0.09704 (5) | 0.0284 (2) | |
H5A | 0.5739 | −0.0274 | 0.0881 | 0.034* | |
H5B | 0.5057 | −0.2342 | 0.0746 | 0.034* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O5 | 0.0224 (3) | 0.0150 (3) | 0.0441 (5) | 0.0008 (3) | −0.0001 (3) | −0.0021 (3) |
O6 | 0.0219 (4) | 0.0272 (5) | 0.0706 (7) | 0.0024 (3) | −0.0106 (4) | 0.0053 (5) |
O7 | 0.0187 (3) | 0.0206 (4) | 0.0417 (5) | 0.0014 (3) | −0.0019 (3) | 0.0026 (3) |
O8 | 0.0244 (4) | 0.0164 (3) | 0.0378 (5) | −0.0035 (3) | 0.0001 (3) | −0.0013 (3) |
C8 | 0.0195 (4) | 0.0160 (4) | 0.0237 (4) | 0.0000 (3) | 0.0026 (3) | 0.0004 (3) |
C9 | 0.0187 (4) | 0.0172 (4) | 0.0299 (5) | 0.0003 (3) | 0.0016 (3) | 0.0008 (4) |
O1 | 0.0189 (4) | 0.0270 (5) | 0.0608 (6) | 0.0032 (3) | −0.0003 (4) | 0.0064 (4) |
O2 | 0.0218 (4) | 0.0144 (3) | 0.0647 (6) | −0.0003 (3) | 0.0039 (4) | −0.0006 (4) |
O3 | 0.0243 (4) | 0.0166 (4) | 0.0532 (6) | −0.0030 (3) | −0.0006 (4) | −0.0024 (4) |
O4 | 0.0180 (3) | 0.0194 (4) | 0.0588 (6) | 0.0012 (3) | 0.0011 (3) | 0.0037 (4) |
C6 | 0.0204 (4) | 0.0166 (4) | 0.0308 (5) | 0.0008 (3) | 0.0032 (4) | 0.0021 (4) |
C7 | 0.0196 (4) | 0.0146 (4) | 0.0304 (5) | −0.0001 (3) | 0.0029 (3) | 0.0002 (4) |
N1 | 0.0172 (3) | 0.0229 (4) | 0.0255 (4) | −0.0018 (3) | 0.0012 (3) | 0.0008 (3) |
N2 | 0.0183 (4) | 0.0270 (5) | 0.0298 (5) | −0.0009 (3) | −0.0022 (3) | 0.0022 (4) |
C1 | 0.0363 (6) | 0.0563 (10) | 0.0291 (6) | −0.0029 (7) | 0.0009 (5) | 0.0108 (6) |
C2 | 0.0234 (4) | 0.0174 (4) | 0.0347 (6) | 0.0014 (4) | 0.0018 (4) | −0.0006 (4) |
C3 | 0.0220 (4) | 0.0276 (5) | 0.0298 (5) | 0.0005 (4) | 0.0034 (4) | −0.0054 (4) |
C4 | 0.0229 (5) | 0.0185 (5) | 0.0437 (7) | 0.0031 (4) | −0.0006 (4) | 0.0006 (5) |
C5 | 0.0221 (4) | 0.0259 (5) | 0.0367 (6) | 0.0013 (4) | 0.0061 (4) | −0.0075 (5) |
O5—C9 | 1.3061 (14) | N2—C4 | 1.4805 (17) |
O5—H5 | 0.8200 | N2—H2C | 0.9000 |
O6—C9 | 1.2070 (13) | N2—H2D | 0.9000 |
O7—C8 | 1.2358 (12) | C1—H1A | 0.9600 |
O8—C8 | 1.2622 (13) | C1—H1B | 0.9600 |
C8—C9 | 1.5437 (16) | C1—H1C | 0.9600 |
O1—C6 | 1.2063 (13) | C2—C3 | 1.5068 (18) |
O2—C6 | 1.3067 (14) | C2—H2A | 0.9700 |
O2—H2 | 0.8200 | C2—H2B | 0.9700 |
O3—C7 | 1.2493 (14) | C3—H3A | 0.9700 |
O4—C7 | 1.2424 (13) | C3—H3B | 0.9700 |
C6—C7 | 1.5530 (16) | C4—C5 | 1.5059 (19) |
N1—C2 | 1.4854 (16) | C4—H4A | 0.9700 |
N1—C5 | 1.4897 (15) | C4—H4B | 0.9700 |
N1—C1 | 1.4934 (17) | C5—H5A | 0.9700 |
N1—H1 | 0.9100 | C5—H5B | 0.9700 |
N2—C3 | 1.4770 (15) | ||
C9—O5—H5 | 109.5 | H1A—C1—H1B | 109.5 |
O7—C8—O8 | 126.96 (10) | N1—C1—H1C | 109.5 |
O7—C8—C9 | 118.57 (9) | H1A—C1—H1C | 109.5 |
O8—C8—C9 | 114.46 (9) | H1B—C1—H1C | 109.5 |
O6—C9—O5 | 125.91 (11) | N1—C2—C3 | 111.87 (10) |
O6—C9—C8 | 121.33 (10) | N1—C2—H2A | 109.2 |
O5—C9—C8 | 112.75 (9) | C3—C2—H2A | 109.2 |
C6—O2—H2 | 109.5 | N1—C2—H2B | 109.2 |
O1—C6—O2 | 125.63 (11) | C3—C2—H2B | 109.2 |
O1—C6—C7 | 122.46 (10) | H2A—C2—H2B | 107.9 |
O2—C6—C7 | 111.90 (9) | N2—C3—C2 | 109.40 (10) |
O4—C7—O3 | 127.31 (10) | N2—C3—H3A | 109.8 |
O4—C7—C6 | 117.67 (9) | C2—C3—H3A | 109.8 |
O3—C7—C6 | 115.01 (9) | N2—C3—H3B | 109.8 |
C2—N1—C5 | 110.32 (9) | C2—C3—H3B | 109.8 |
C2—N1—C1 | 109.73 (11) | H3A—C3—H3B | 108.2 |
C5—N1—C1 | 110.72 (11) | N2—C4—C5 | 110.04 (10) |
C2—N1—H1 | 108.7 | N2—C4—H4A | 109.7 |
C5—N1—H1 | 108.7 | C5—C4—H4A | 109.7 |
C1—N1—H1 | 108.7 | N2—C4—H4B | 109.7 |
C3—N2—C4 | 110.41 (9) | C5—C4—H4B | 109.7 |
C3—N2—H2C | 109.6 | H4A—C4—H4B | 108.2 |
C4—N2—H2C | 109.6 | N1—C5—C4 | 110.90 (10) |
C3—N2—H2D | 109.6 | N1—C5—H5A | 109.5 |
C4—N2—H2D | 109.6 | C4—C5—H5A | 109.5 |
H2C—N2—H2D | 108.1 | N1—C5—H5B | 109.5 |
N1—C1—H1A | 109.5 | C4—C5—H5B | 109.5 |
N1—C1—H1B | 109.5 | H5A—C5—H5B | 108.0 |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O3i | 0.82 | 1.72 | 2.5242 (17) | 167 |
O5—H5···O8ii | 0.82 | 1.74 | 2.5467 (16) | 169 |
N1—H1···O4 | 0.91 | 1.92 | 2.7452 (15) | 151 |
N1—H1···O2 | 0.91 | 2.27 | 2.9085 (13) | 127 |
N2—H2C···O8iii | 0.90 | 2.03 | 2.8080 (14) | 144 |
N2—H2C···O6iii | 0.90 | 2.51 | 3.2564 (19) | 141 |
N2—H2D···O7iv | 0.90 | 1.93 | 2.7633 (16) | 154 |
N2—H2D···O5iv | 0.90 | 2.32 | 2.9243 (13) | 125 |
C1—H1B···O3v | 0.96 | 2.45 | 3.2653 (19) | 142 |
C2—H2A···O4i | 0.97 | 2.44 | 3.3533 (18) | 157 |
C3—H3A···O6vi | 0.97 | 2.49 | 3.4334 (18) | 163 |
C3—H3B···O8ii | 0.97 | 2.29 | 3.2319 (15) | 164 |
C4—H4B···O7vii | 0.97 | 2.43 | 3.3665 (18) | 163 |
C5—H5A···O3viii | 0.97 | 2.28 | 3.2269 (16) | 165 |
Symmetry codes: (i) x, y+1, z; (ii) x, y−1, z; (iii) −x+1, y−1, −z+1/2; (iv) x+1/2, y−1/2, z; (v) −x+1/2, −y−1/2, −z; (vi) −x+1, y, −z+1/2; (vii) x+1/2, y−3/2, z; (viii) x+1/2, y+1/2, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O3i | 0.82 | 1.72 | 2.5242 (17) | 166.9 |
O5—H5···O8ii | 0.82 | 1.74 | 2.5467 (16) | 169.3 |
N1—H1···O4 | 0.91 | 1.92 | 2.7452 (15) | 150.7 |
N1—H1···O2 | 0.91 | 2.27 | 2.9085 (13) | 127.0 |
N2—H2C···O8iii | 0.90 | 2.03 | 2.8080 (14) | 144.0 |
N2—H2C···O6iii | 0.90 | 2.51 | 3.2564 (19) | 140.9 |
N2—H2D···O7iv | 0.90 | 1.93 | 2.7633 (16) | 153.6 |
N2—H2D···O5iv | 0.90 | 2.32 | 2.9243 (13) | 124.9 |
C1—H1B···O3v | 0.96 | 2.45 | 3.2653 (19) | 142.3 |
C2—H2A···O4i | 0.97 | 2.44 | 3.3533 (18) | 157.2 |
C3—H3A···O6vi | 0.97 | 2.49 | 3.4334 (18) | 163.3 |
C3—H3B···O8ii | 0.97 | 2.29 | 3.2319 (15) | 163.6 |
C4—H4B···O7vii | 0.97 | 2.43 | 3.3665 (18) | 162.6 |
C5—H5A···O3viii | 0.97 | 2.28 | 3.2269 (16) | 165.4 |
Symmetry codes: (i) x, y+1, z; (ii) x, y−1, z; (iii) −x+1, y−1, −z+1/2; (iv) x+1/2, y−1/2, z; (v) −x+1/2, −y−1/2, −z; (vi) −x+1, y, −z+1/2; (vii) x+1/2, y−3/2, z; (viii) x+1/2, y+1/2, z. |
Acknowledgements
This work was supported by the Tunisian Ministry of High Education Scientific Research.
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Piperazine and its derivatives have been intensively investigated owing to their interesting pharmacological, cardiovascular and autonomic properties (Conrado et al., 2008). Piperazine derivatives are found in biologically active compounds across a number of different therapeutic areas such as antifungal, antibacterial, antimalarial, antipsychotic, antidepressant and antitumour activity against colon, prostate, breast, lung and leukemia tumors (Brockunier et al., 2004; Bogatcheva et al., 2006; Essid et al., 2013). In the present work, we report the preparation and the crystal structure of an organic proton transfer salt (C5H14N2)2+·2(HC2O4)-, (I). The asymmetric unit of (I) contains one 1-methylpiperazin-1,4-diium dication and two semi-oxalate anions (Fig. 1). 1-Methylpiperazine is diprotonated at atom N1 and N2 and oxalic acid is mono-deprotonated. The oxalate monoanions are essentially planar, with dihedral angles between the carboxylate groups of less than 4°. Two strong O–H···O (Table 1) hydrogen bonds generate linear oxalate chains running parallel to the b axis (Fig. 2). The geometrical parameters of these chains correlate well with the corresponding values found in related crystal structures (Essid et al., 2013; Vaidhyanathan et al., 2002; Ejsmont & Zaleski, 2006). Bond distances around atom C7 and C8 indicate a carboxylate group with delocalization of the negative charge between atoms O3 and O4, and between O7 and O8. In the hydrogenoxalate anion HC2O4-, the H atoms are located at O2 and O5. The position of protonation is also indicated by elongation of the corresponding C–O distances [O2–C6 = 1.306 (2) Å, O5–C9 = 1.306 (1) Å]. The bond lengths of C6–C7 and C8–C9 are relatively long [1.553 (2) Å, 1.544 (2) Å] as expected for an oxalate anion. Geometrical parameters of the methylpiperazin-1,4-dium dications are found to be in agreement with those of another similar structure of methylpiperazin-1,4-diium dipicrate (Dutkiewicz et al., 2011). The cyclic amine adopts a chair conformation with the methyl group occupying an equatorial position, with puckering parameters: Q = 0.5772 (11) A, θ = 2.85 (11)° and φ = -174 (2)° (Cremer & Pople, 1975) and atoms N1 and N2 deviating by -0.308 (2) and 0.333 (2) Å from the least-squares plane defined by the remaining atoms in the ring. In addition, the crystal structure of [C5H14N2](HC2O4)2 is stabilized by ionic interactions between the 1-methylpiperazin-1,4-dium dications and the oxalate monoanions chains, as well as by a network of N–H···O and C–H···O hydrogen bonds (Fig. 3 and Table 1) such that all the hydrogen atoms bonded to nitrogen atoms participate in the formation of these hydrogen bonds, with donor-acceptor distances between 2.745 (2) and 3.433 (2) Å (Table 1).