1-Methyl-piperazine-1,4-dium bis-(hydrogen oxalate).

In the crystal structure of the title compound, C5H14N2 (2+)·2HC2O4 (-), the two crystallographically independent hydrogen oxalate anions are linked by strong inter-molecular 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.

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

C5H14N2 2+·2C2HO4 −

M = 280.24

Monoclinic,

a = 15.649 (2) Å

b = 5.681 (3) Å

c = 27.230 (2) Å

β = 104.05 (2)°

V = 2348.4 (13) Å3

Z = 8

Ag Kα radiation

λ = 0.56083 Å

μ = 0.08 mm−1

T = 293 K

0.35 × 0.25 × 0.15 mm

Data collection

Enraf–Nonius CAD-4 diffractometer

7879 measured reflections

5758 independent reflections

3621 reflections with I > 2σ(I)

R int = 0.027

2 standard reflections every 120 min intensity decay: none

Refinement

R[F 2 > 2σ(F 2)] = 0.052

wR(F 2) = 0.162

S = 1.01

5757 reflections

175 parameters

H-atom parameters constrained

Δρmax = 0.41 e Å−3

Δρmin = −0.40 e Å−3

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ▶); cell refinement: 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 ▶).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536814003559/zl2578sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814003559/zl2578Isup2.hkl

CCDC reference: 987380

Additional supporting information: crystallographic information; 3D view; checkCIF report

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

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

Table 1

Hydrogen-bond geometry (Å, °)

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) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) .