A monoclinic form of N,N,N',N'-tetra­kis(carboxy­meth­yl)ethyl­enediammonium dichloride trihydrate

The crystal structure of a monoclinic form of the title compound, C₁₀H₁₈N₂O₈²⁺·2Cl^-·3H₂O or (H₆edta)Cl₂·3H₂O, is reported. The first published form had space group P1 [Mistryukov, Mikhailov, Sergeev, Zhuravlov, Schelokov, Chernov, Fodorov & Brekhovskikh (1987). Dokl. Akad. Nauk SSSR, 295, 1390-1393], while the structure reported here has P2/c. A crystallographic twofold rotation axis passes through the mid-point of the central C-C bond of the cation; another twofold axis passes through one water O atom. In the crystal structure, the (H₆edta)²⁺ and Cl^- ions and water mol­ecules are linked via hydrogen bonds, forming two-dimensional networks. The NH groups and carbonyl O atoms form trifurcated hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 170 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.034
• wR factor = 0.075
• Data-to-parameter ratio = 17.0

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT222_ALERT_3_B Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       4.92 Ratio
PLAT355_ALERT_3_B Long    O-H Bond (0.82A)   O1     -   H1O    ...       1.11 Ang.
PLAT417_ALERT_2_B Short Inter D-H..H-D       H1O    ..  H5OB    ..       1.96 Ang.
PLAT417_ALERT_2_B Short Inter D-H..H-D       H5OA   ..  H1O     ..       1.97 Ang.

Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.98
PLAT230_ALERT_2_C Hirshfeld Test Diff for    O2     -   C1      ..       5.69 su
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          2

   0 ALERT level A = In general: serious problem
   4 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The title molecule, (I), in this second polymorphic form (Fig. 1) differs from the reported structure (Mistryukov et al., 1987) and possesses twofold crystallographically imposed symmetry axis. The major difference between the polymorphs is found in the N–C–C–N torsion angle. Namely, in the reported structure ethylenediamine part was found to be antiperiplanar (torsion angle N–C–C–N = 180.2°) and here it is in gauche conformation (torsion angle N–C–C–N = 68.3 (2)°).

The structure of title compound is stabilized by intramolecular and intermolecular H-bonds (Table 2). The title compound shows a trifurcated intramolecular H-bond involving three carbonyl O atoms (O2, O4 and O4ⁱ) and N—H moieties. The formation of the N–H···O intramolecular hydrogen bonds (Fig. 1) leads to the formation of five-membered (with O2 and O4) and eight membered rings (involving O4ⁱ) closed by H-bonding. The H₆edta²⁺ cations are bonded in infinite chains through H-bonds via water molecules and chloride anions (O1—H···O5—H···Cl1···H—O3; Fig. 2). Long O1—H1O and short H1O···O5 bond lenghts are found within the structure. This is commonly observed in acidic O···H···O bridges (Steiner, 1999). The infinite chains are connected via H-bonds between the O6 of one water molecule and O5 atoms of two other water molecules and two chloride anions (Fig. 2).

Related literature

For related literature, see: Mistryukov et al. (1987); Steiner (1999).

S2. Experimental

The title compound was obtained unintentionally as the product of an attempt to syntesize [NiCl₂(Me₄edta)] by the reaction of NiCl₂ (0.5 mmol) and Me₄edta (0.5 mmol) in water (20 ml). The solution was stirred for 3 h at room temperature. By slow evaporation over two weeks colorless crystals of the title compound were afforded due to hydrolysis of starting material Me₄edta.

S3. Refinement

All H atoms were found.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Version 1.076; Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. ORTEP representation of H6edta^2+ cation in the title compound. Displacement ellipsoids are plotted at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. [Symmetry code: (i) –x + 1/2, y, –z + 3/2]
	Fig. 2. Network of H-bongind viewed normal to b-axis.

N,N,N',N'-tetrakis(carboxymethyl)ethylenediammonium dichloride trihydrate

Crystal data

C10H18N2O8^2+·2Cl^−·3H2O	F(000) = 440
Mr = 419.21	Dx = 1.535 Mg m^−3
Monoclinic, P2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yc	Cell parameters from 3118 reflections
a = 11.6817 (4) Å	θ = 2.5–32.2°
b = 5.5845 (2) Å	µ = 0.42 mm^−1
c = 16.4627 (6) Å	T = 170 K
β = 122.372 (3)°	Small needle, colourless
V = 907.06 (6) Å^3	0.4 × 0.05 × 0.05 mm
Z = 2

Data collection

Oxford Diffraction Xcalibur S CCD diffractometer	2762 independent reflections
Graphite monochromator	1740 reflections with I > 2σ(I)
Detector resolution: 16.356 pixels mm^-1	Rint = 0.042
ω and φ scans	θmax = 30.5°, θmin = 2.5°
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006)	h = −16→16
Tmin = 0.992, Tmax = 1	k = −7→7
10960 measured reflections	l = −23→23

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.034	Hydrogen site location: difference Fourier map
wR(F^2) = 0.075	All H-atom parameters refined
S = 0.92	w = 1/[σ^2(Fo^2) + (0.0347P)^2] where P = (Fo^2 + 2Fc^2)/3
2762 reflections	(Δ/σ)max < 0.001
162 parameters	Δρmax = 0.50 e Å^−3
0 restraints	Δρmin = −0.25 e Å^−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
O3	0.40757 (12)	0.3165 (2)	0.42566 (8)	0.0232 (3)
O4	0.41403 (10)	0.34559 (18)	0.29282 (7)	0.0201 (2)
O5	1.08106 (13)	0.5932 (2)	0.65974 (9)	0.0292 (3)
O6	0	1.1041 (3)	0.25	0.0294 (4)
C3	0.57529 (15)	−0.1579 (3)	0.28642 (10)	0.0157 (3)
C4	0.55585 (15)	0.0606 (3)	0.41261 (10)	0.0163 (3)
C5	0.45072 (14)	0.2554 (3)	0.37004 (10)	0.0159 (3)
H3O	0.347 (2)	0.433 (4)	0.3983 (14)	0.056 (7)*
H4A	0.5124 (15)	−0.091 (3)	0.4094 (10)	0.013 (4)*
H4B	0.6221 (15)	0.099 (3)	0.4786 (11)	0.016 (4)*
H5OA	1.038 (3)	0.689 (5)	0.678 (2)	0.110 (11)*
H5OB	1.145 (3)	0.498 (5)	0.716 (2)	0.105 (10)*
H6O	0.071 (2)	1.021 (4)	0.2792 (16)	0.065 (8)*
H1N	0.6095 (18)	0.172 (3)	0.3266 (13)	0.030 (5)*
H1O	0.988 (2)	0.419 (4)	0.5885 (15)	0.064 (7)*
H2A	0.8135 (16)	0.010 (3)	0.3860 (11)	0.025 (4)*
H2B	0.7973 (16)	−0.096 (3)	0.4646 (12)	0.022 (4)*
H3A	0.5973 (15)	−0.295 (3)	0.3238 (11)	0.015 (4)*
H3B	0.6279 (15)	−0.159 (2)	0.2570 (10)	0.013 (4)*
Cl1	0.24726 (4)	0.76000 (7)	0.33996 (3)	0.02310 (11)
O1	0.95474 (10)	0.2511 (2)	0.54558 (7)	0.0233 (2)
O2	0.75640 (11)	0.44325 (18)	0.45465 (7)	0.0205 (2)
N1	0.62474 (12)	0.0450 (2)	0.35771 (8)	0.0142 (3)
C1	0.82708 (14)	0.2676 (3)	0.47641 (10)	0.0176 (3)
C2	0.77559 (15)	0.0331 (3)	0.42386 (11)	0.0196 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O3	0.0295 (6)	0.0246 (6)	0.0206 (6)	0.0057 (5)	0.0169 (5)	0.0018 (5)
O4	0.0245 (6)	0.0201 (5)	0.0168 (5)	0.0051 (5)	0.0118 (5)	0.0028 (4)
O5	0.0249 (7)	0.0307 (7)	0.0245 (6)	−0.0011 (6)	0.0083 (5)	−0.0043 (5)
O6	0.0222 (10)	0.0222 (9)	0.0391 (10)	0	0.0133 (8)	0
C3	0.0182 (7)	0.0109 (7)	0.0137 (7)	0.0008 (6)	0.0058 (6)	−0.0006 (6)
C4	0.0178 (7)	0.0173 (8)	0.0129 (7)	−0.0015 (6)	0.0077 (6)	0.0009 (6)
C5	0.0161 (7)	0.0148 (7)	0.0161 (7)	−0.0041 (6)	0.0082 (6)	−0.0036 (6)
Cl1	0.02071 (19)	0.0243 (2)	0.02212 (19)	0.00210 (18)	0.01002 (15)	−0.00208 (17)
O1	0.0145 (5)	0.0230 (6)	0.0207 (6)	0.0005 (5)	0.0017 (4)	−0.0033 (5)
O2	0.0204 (6)	0.0147 (5)	0.0203 (5)	0.0016 (5)	0.0068 (5)	0.0013 (4)
N1	0.0150 (6)	0.0113 (6)	0.0135 (6)	−0.0001 (5)	0.0057 (5)	0.0002 (5)
C1	0.0155 (7)	0.0206 (8)	0.0147 (7)	−0.0016 (7)	0.0068 (6)	0.0007 (6)
C2	0.0146 (8)	0.0172 (8)	0.0207 (8)	0.0022 (6)	0.0052 (6)	0.0014 (7)

Geometric parameters (Å, º)

O3—C5	1.3049 (16)	O1—H1O	1.11 (2)
O4—C5	1.2124 (16)	O3—H3O	0.89 (2)
C3—N1	1.5066 (18)	N1—H1N	0.836 (17)
C3—C3^i	1.508 (3)	C2—H2A	0.947 (19)
C4—N1	1.5003 (18)	C2—H2B	0.923 (17)
C4—C5	1.504 (2)	C3—H3A	0.928 (16)
O1—C1	1.3080 (17)	C3—H3B	0.965 (19)
O2—C1	1.2063 (17)	C4—H4A	0.974 (17)
N1—C2	1.4968 (19)	C4—H4B	0.962 (16)
C1—C2	1.506 (2)
N1—C3—C3^i	114.64 (11)	C4—N1—H1N	108.2 (15)
N1—C4—C5	109.19 (12)	N1—C2—H2A	108.1 (11)
O4—C5—O3	125.08 (14)	N1—C2—H2B	108.8 (13)
O4—C5—C4	122.08 (12)	C1—C2—H2A	108.2 (11)
O3—C5—C4	112.82 (12)	C1—C2—H2B	113.1 (10)
C2—N1—C4	111.51 (11)	H2A—C2—H2B	109.2 (16)
C2—N1—C3	110.14 (11)	N1—C3—H3A	104.4 (10)
C4—N1—C3	114.03 (11)	N1—C3—H3B	108.3 (8)
O2—C1—O1	126.59 (14)	H3A—C3—H3B	107.6 (14)
O2—C1—C2	122.48 (13)	H3A—C3—C3^i	108.6 (12)
O1—C1—C2	110.93 (13)	H3B—C3—C3^i	112.7 (9)
N1—C2—C1	109.38 (12)	N1—C4—H4A	110.4 (11)
C1—O1—H1O	110.0 (12)	N1—C4—H4B	109.1 (12)
C5—O3—H3O	109.8 (15)	C5—C4—H4A	109.4 (11)
C2—N1—H1N	105.4 (15)	C5—C4—H4B	109.1 (11)
C3—N1—H1N	107.1 (12)	H4A—C4—H4B	109.6 (13)

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5OA···O6^ii	0.89 (3)	1.87 (3)	2.7329 (18)	163 (3)
O5—H5OB···Cl1^iii	0.98 (3)	2.25 (3)	3.2085 (13)	167 (3)
N1—H1N···O2	0.836 (17)	2.410 (18)	2.6889 (15)	100.3 (14)
N1—H1N···O4	0.836 (17)	2.26 (2)	2.6837 (18)	111.7 (19)
N1—H1N···O4^i	0.836 (17)	2.074 (19)	2.8218 (16)	148.6 (18)
O1—H1O···O5	1.11 (2)	1.46 (2)	2.5278 (16)	158 (2)
O3—H3O···Cl1	0.89 (2)	2.10 (2)	2.9669 (13)	165 (2)
O6—H6O···Cl1	0.84 (2)	2.27 (2)	3.1062 (11)	172 (2)

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