3,3'-(Piperazine-1,4-diium-1,4-di-yl)di-propionate dihydrate.

During the recrystallization of 3-[4-(2-carb-oxy-eth-yl)piperazin-1-yl]propionic acid, the carb-oxy-lic acid H atoms were transferred to the piperazine N atoms, forming the title compound, C(10)H(18)N(2)O(4)·2H(2)O, in which the zwitterion lies about an inversion center. In the crystal, bifurcated N-H⋯(O,O) hydrogen bonds connect the zwitterions into a two-dimensional framework parallel to (-102) forming R(4) (4)(30) rings. O-H⋯O hydrogen bonds involving the solvent water mol-ecules connect the two-dimensional framework into a three-dimensional network. In addition, weak C-H⋯O hydrogen bonds are observed.

Related literature

For general background and applications of carb­oxy­lic acids, see: Jin et al. (2012 ▶); Grossel et al. (2006 ▶); Rueff et al. (2001 ▶); Strachan et al. (2007 ▶); Desiraju (2002 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C10H18N2O4·2H2O

M = 266.30

Monoclinic,

a = 6.8028 (6) Å

b = 8.8925 (7) Å

c = 10.4301 (11) Å

β = 101.780 (1)°

V = 617.67 (10) Å3

Z = 2

Mo Kα radiation

μ = 0.12 mm−1

T = 298 K

0.43 × 0.40 × 0.32 mm

Data collection

Bruker SMART CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2002 ▶) T min = 0.951, T max = 0.963

2951 measured reflections

1087 independent reflections

895 reflections with I > 2σ(I)

R int = 0.023

Refinement

R[F 2 > 2σ(F 2)] = 0.040

wR(F 2) = 0.111

S = 1.06

1087 reflections

82 parameters

H-atom parameters constrained

Δρmax = 0.21 e Å−3

Δρmin = −0.23 e Å−3

Data collection: SMART (Bruker, 2002 ▶); cell refinement: SAINT (Bruker, 2002 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXTL.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812037312/lh5520sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812037312/lh5520Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812037312/lh5520Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C10H18N2O4·2H2O	F(000) = 288
Mr = 266.30	Dx = 1.432 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1525 reflections
a = 6.8028 (6) Å	θ = 3.0–28.2°
b = 8.8925 (7) Å	µ = 0.12 mm−1
c = 10.4301 (11) Å	T = 298 K
β = 101.780 (1)°	Block, colorless
V = 617.67 (10) Å3	0.43 × 0.40 × 0.32 mm
Z = 2

Bruker SMART CCD diffractometer	1087 independent reflections
Radiation source: fine-focus sealed tube	895 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
φ and ω scans	θmax = 25.0°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −8→7
Tmin = 0.951, Tmax = 0.963	k = −10→5
2951 measured reflections	l = −12→11

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)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.111	H-atom parameters constrained
S = 1.06	w = 1/[σ2(Fo2) + (0.0526P)2 + 0.3063P] where P = (Fo2 + 2Fc2)/3
1087 reflections	(Δ/σ)max < 0.001
82 parameters	Δρmax = 0.21 e Å−3
0 restraints	Δρmin = −0.23 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
N1	0.15979 (19)	0.08898 (15)	0.08004 (12)	0.0204 (3)
H1	0.2428	0.0121	0.1137	0.024*
O1	0.56844 (18)	0.37957 (15)	0.31249 (12)	0.0340 (4)
O2	0.7046 (2)	0.4517 (2)	0.14744 (14)	0.0551 (5)
O3	0.8070 (2)	0.10838 (18)	0.40824 (15)	0.0541 (5)
H3E	0.7405	0.1861	0.3781	0.065*
H3F	0.7788	0.0870	0.4818	0.065*
C1	0.5838 (2)	0.3752 (2)	0.19346 (17)	0.0288 (4)
C2	0.4531 (3)	0.2636 (2)	0.10320 (18)	0.0335 (5)
H2A	0.4302	0.3019	0.0143	0.040*
H2B	0.5256	0.1694	0.1049	0.040*
C3	0.2521 (3)	0.23274 (19)	0.13874 (17)	0.0276 (4)
H3A	0.2697	0.2274	0.2333	0.033*
H3B	0.1616	0.3154	0.1084	0.033*
C4	−0.0379 (2)	0.06441 (19)	0.11862 (16)	0.0236 (4)
H4A	−0.1283	0.1462	0.0851	0.028*
H4B	−0.0187	0.0648	0.2134	0.028*
C5	0.1314 (2)	0.08320 (19)	−0.06607 (15)	0.0230 (4)
H5A	0.2604	0.0950	−0.0910	0.028*
H5B	0.0456	0.1656	−0.1042	0.028*

	U11	U22	U33	U12	U13	U23
N1	0.0183 (7)	0.0214 (7)	0.0211 (7)	−0.0005 (5)	0.0031 (5)	−0.0011 (6)
O1	0.0355 (7)	0.0386 (8)	0.0274 (7)	−0.0108 (6)	0.0049 (5)	−0.0046 (6)
O2	0.0584 (9)	0.0713 (11)	0.0388 (8)	−0.0414 (9)	0.0174 (7)	−0.0142 (8)
O3	0.0650 (10)	0.0500 (10)	0.0518 (10)	0.0019 (8)	0.0225 (8)	0.0053 (8)
C1	0.0261 (9)	0.0297 (9)	0.0300 (10)	−0.0040 (7)	0.0044 (7)	−0.0036 (8)
C2	0.0317 (10)	0.0379 (11)	0.0317 (10)	−0.0112 (8)	0.0084 (8)	−0.0090 (8)
C3	0.0249 (9)	0.0256 (9)	0.0317 (9)	−0.0040 (7)	0.0046 (7)	−0.0064 (7)
C4	0.0201 (8)	0.0287 (9)	0.0224 (8)	0.0000 (7)	0.0056 (6)	−0.0013 (7)
C5	0.0214 (8)	0.0279 (9)	0.0202 (8)	−0.0010 (7)	0.0050 (6)	0.0022 (7)

N1—C4	1.4966 (19)	C2—H2A	0.9700
N1—C5	1.4975 (19)	C2—H2B	0.9700
N1—C3	1.499 (2)	C3—H3A	0.9700
N1—H1	0.9100	C3—H3B	0.9700
O1—C1	1.267 (2)	C4—C5i	1.512 (2)
O2—C1	1.237 (2)	C4—H4A	0.9700
O3—H3E	0.8501	C4—H4B	0.9700
O3—H3F	0.8500	C5—C4i	1.512 (2)
C1—C2	1.523 (2)	C5—H5A	0.9700
C2—C3	1.513 (2)	C5—H5B	0.9700
C4—N1—C5	109.42 (12)	N1—C3—H3A	109.2
C4—N1—C3	109.84 (12)	C2—C3—H3A	109.2
C5—N1—C3	113.65 (13)	N1—C3—H3B	109.2
C4—N1—H1	107.9	C2—C3—H3B	109.2
C5—N1—H1	107.9	H3A—C3—H3B	107.9
C3—N1—H1	107.9	N1—C4—C5i	111.35 (13)
H3E—O3—H3F	108.3	N1—C4—H4A	109.4
O2—C1—O1	123.88 (16)	C5i—C4—H4A	109.4
O2—C1—C2	117.96 (16)	N1—C4—H4B	109.4
O1—C1—C2	118.09 (15)	C5i—C4—H4B	109.4
C3—C2—C1	114.16 (15)	H4A—C4—H4B	108.0
C3—C2—H2A	108.7	N1—C5—C4i	110.85 (13)
C1—C2—H2A	108.7	N1—C5—H5A	109.5
C3—C2—H2B	108.7	C4i—C5—H5A	109.5
C1—C2—H2B	108.7	N1—C5—H5B	109.5
H2A—C2—H2B	107.6	C4i—C5—H5B	109.5
N1—C3—C2	112.25 (14)	H5A—C5—H5B	108.1
O2—C1—C2—C3	−151.50 (18)	C5—N1—C4—C5i	57.11 (18)
O1—C1—C2—C3	31.5 (2)	C3—N1—C4—C5i	−177.48 (13)
C4—N1—C3—C2	179.91 (14)	C4—N1—C5—C4i	−56.82 (18)
C5—N1—C3—C2	−57.14 (19)	C3—N1—C5—C4i	−179.99 (13)
C1—C2—C3—N1	−160.56 (15)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3F···O2ii	0.85	1.93	2.776 (2)	177
O3—H3E···O1	0.85	2.11	2.964 (2)	177
N1—H1···O2iii	0.91	2.50	3.0577 (19)	120
N1—H1···O1iii	0.91	1.80	2.7011 (18)	172
C4—H4B···O3iv	0.97	2.58	3.419 (2)	145
C4—H4B···O2iii	0.97	2.53	3.137 (2)	120
C5—H5A···O1v	0.97	2.51	3.477 (2)	172

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3F⋯O2i	0.85	1.93	2.776 (2)	177
O3—H3E⋯O1	0.85	2.11	2.964 (2)	177
N1—H1⋯O2ii	0.91	2.50	3.0577 (19)	120
N1—H1⋯O1ii	0.91	1.80	2.7011 (18)	172
C4—H4B⋯O3iii	0.97	2.58	3.419 (2)	145
C4—H4B⋯O2ii	0.97	2.53	3.137 (2)	120
C5—H5A⋯O1iv	0.97	2.51	3.477 (2)	172

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .