Hydro­gen bonding in ethyl­ene­di­ammonium bis­(hydrogen malonate) mono­hydrate

In the title compound, C₂H₁₀N₂²⁺·2C₃H₃O₄^-·H₂O, the hydrogen malonate anion has an intramolecular O-H...O hydrogen bond of 2.430 (2) Å. The water mol­ecule lies on a twofold axis and connects the anions into pairs through hydrogen bonds of 2.734 (1) Å. The ethyl­enedi­ammonium cation lies across an inversion centre. Each of the ammonium protons is involved in hydrogen bonding to an anion or a water mol­ecule [N...O 2.815 (2)-2.875 (2) Å].

S1. Comment

Reaction of an amine with a polycarboxylic acid often gives crystals of only one of the possible salts. Frequently, the dominant compound contains a partially ionized acid group, such as hydrogen oxalate or hydrogen malonate, to optimize hydrogen bonding. The hydrogen bonding may be extended further by water molecules (Barnes & Barnes, 1996; Barnes et al., 1998). In the present work, ethylenediammonium bis(hydrogen malonate) monohydrate, (I), was the only crystalline product from aqueous mixtures of 1,2-diaminoethane and malonic acid.

Golic (Djinovic et al., 1990; Djinovic & Golic, 1991) has discussed the structural patterns of the hydrogenmalonate ion. The acidic proton is used either to form chains by inter-anion hydrogen bonding or, as in (I), in an asymmetric intramolecular hydrogen bond. In (I), the R₁¹(6) ring (Bernstein et al., 1995) ···O═C—C—C—O—H··· is more symmetrical than in, for example, benzylammonium hydrogen malonate (Djinovic et al., 1990) [values in brackets], with O8—H81 1.13 (2) Å [0.80 Å] and H8···O7 1.33 (2) Å [1.67 Å]. In (I), C4—C5 is only 3σ shorter than C3—C4 compared with 7σ in benzylammonium hydrogen malonate.

The water molecule, O10, lies on the twofold axis. Hydrogen bonds connect the anions into pairs [O10—H101···O6 2.734 (1) Å] and the centrosymmetric cations into chains [N1—H1B···O10 2.848 (2) Å]. The ammonium protons H1A and H1C form hydrogen bonds to O6 and O9 of separate anions (see Table 2).

S2. Experimental

Crystals were grown by slow evaporation of an aqueous mixture of 1,2-diaminoethane and malonic acid (1:1).

Computing details

Data collection: CAD-4-PC (Enraf-Nonius, 1993); cell refinement: CAD-4-PC; data reduction: XCAD4 (Harms & Wocadlo, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97.

Ethylene diammonium bis(hydrogenmalonate) monohydrate

Crystal data

C2H10N2^2+·2C3H3O4^−·H2O	F(000) = 304
Mr = 286.24	Dx = 1.483 Mg m^−3
Monoclinic, P2/n	Mo Kα radiation, λ = 0.71073 Å
a = 8.0276 (10) Å	Cell parameters from 25 reflections
b = 8.7013 (11) Å	θ = 14.4–15.0°
c = 9.543 (2) Å	µ = 0.14 mm^−1
β = 105.901 (13)°	T = 293 K
V = 641.05 (18) Å^3	Block, colourless
Z = 2	0.52 × 0.50 × 0.25 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.017
Radiation source: fine-focus sealed tube	θmax = 30.0°, θmin = 2.3°
Graphite monochromator	h = −1→11
ω–2θ scans	k = 0→12
2227 measured reflections	l = −13→13
1865 independent reflections	3 standard reflections every 60 min
1441 reflections with I > 2σ(I)	intensity decay: 1%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.044	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.159	w = 1/[σ^2(Fo^2) + (0.1366P)^2 + 0.1458P] where P = (Fo^2 + 2Fc^2)/3
S = 0.79	(Δ/σ)max < 0.001
1865 reflections	Δρmax = 0.32 e Å^−3
100 parameters	Δρmin = −0.23 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.35 (3)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.20214 (16)	0.92650 (13)	0.46134 (15)	0.0463 (3)
H1A	0.2901	0.8715	0.5150	0.060*
H1B	0.2414	1.0163	0.4389	0.060*
H1C	0.1518	0.8755	0.3799	0.060*
C2	0.07509 (16)	0.95326 (15)	0.54433 (13)	0.0362 (3)
H21	0.131 (2)	1.008 (2)	0.632 (2)	0.047*
H22	0.039 (2)	0.855 (2)	0.571 (2)	0.047*
C3	0.37077 (16)	0.59023 (15)	0.62151 (13)	0.0354 (3)
C4	0.48180 (16)	0.45300 (15)	0.68777 (14)	0.0377 (3)
H4A	0.5902	0.4601	0.6617	0.049*
H4B	0.5090	0.4618	0.7930	0.049*
C5	0.40674 (19)	0.29445 (16)	0.64540 (14)	0.0447 (4)
O6	0.43623 (14)	0.71955 (13)	0.64001 (14)	0.0542 (3)
O7	0.21513 (13)	0.56566 (13)	0.54908 (12)	0.0491 (3)
O8	0.24639 (17)	0.28811 (15)	0.56815 (14)	0.0602 (4)
H81	0.208 (3)	0.413 (3)	0.552 (2)	0.078*
O9	0.4933 (2)	0.17887 (14)	0.68295 (14)	0.0655 (4)
O10	0.7500	0.85931 (16)	0.7500	0.0446 (4)
H101	0.661 (2)	0.800 (2)	0.718 (2)	0.058*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0447 (6)	0.0394 (6)	0.0568 (7)	0.0063 (4)	0.0175 (5)	0.0105 (5)
C2	0.0356 (6)	0.0346 (6)	0.0352 (6)	0.0009 (4)	0.0045 (5)	0.0038 (4)
C3	0.0331 (5)	0.0385 (6)	0.0342 (5)	−0.0008 (4)	0.0083 (4)	0.0025 (4)
C4	0.0342 (6)	0.0415 (6)	0.0350 (6)	0.0016 (5)	0.0056 (4)	0.0024 (5)
C5	0.0592 (9)	0.0393 (7)	0.0371 (6)	0.0005 (6)	0.0158 (6)	0.0019 (5)
O6	0.0452 (6)	0.0388 (6)	0.0710 (7)	−0.0047 (4)	0.0030 (5)	0.0077 (5)
O7	0.0343 (5)	0.0508 (6)	0.0537 (6)	−0.0007 (4)	−0.0024 (4)	0.0033 (4)
O8	0.0622 (7)	0.0474 (6)	0.0633 (7)	−0.0162 (5)	0.0043 (6)	−0.0061 (5)
O9	0.0931 (10)	0.0430 (6)	0.0618 (7)	0.0161 (6)	0.0235 (7)	0.0089 (5)
O10	0.0420 (7)	0.0351 (7)	0.0555 (8)	0.000	0.0110 (6)	0.000

Geometric parameters (Å, º)

N1—C2	1.4711 (18)	C3—C4	1.5203 (17)
C2—C2^i	1.507 (2)	C4—C5	1.5154 (19)
C3—O6	1.2340 (17)	C5—O9	1.2192 (19)
C3—O7	1.2693 (15)	C5—O8	1.2975 (19)
N1—C2—C2^i	110.44 (13)	C5—C4—C3	117.33 (11)
O6—C3—O7	123.27 (12)	O9—C5—O8	121.92 (15)
O6—C3—C4	118.59 (11)	O9—C5—C4	121.31 (14)
O7—C3—C4	118.14 (12)	O8—C5—C4	116.77 (12)
N1—C2—C2^i—N1^i	180.0	O7—C3—C4—C5	8.24 (18)
O6—C3—C4—C5	−171.40 (12)	C3—C4—C5—O9	173.16 (13)
C3—C4—C5—O8	−7.13 (18)

Symmetry code: (i) −x, −y+2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O6	0.89	1.94	2.8152 (16)	166
N1—H1B···O10^ii	0.89	2.12	2.8483 (15)	139
N1—H1C···O9^iii	0.89	2.02	2.875 (2)	162
O8—H81···O7	1.13 (2)	1.33 (2)	2.4297 (17)	162 (2)
O10—H101···O6	0.87 (2)	1.889 (19)	2.7342 (13)	165 (2)

Symmetry codes: (ii) −x+1, −y+2, −z+1; (iii) x−1/2, −y+1, z−1/2.