Triclinic modification of diaqua-bis-(5-carb-oxy-1H-imidazole-4-carboxyl-ato-κ(2)N(3),O(4))iron(II).

The title compound, [Fe(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)], is a triclinic modification of a monoclinic form recently reported by Du et al. [Acta Cryst. (2011) ▶, E67, m997]. The Fe(II) ion lies at an inversion center and is coordinated by two N and two O atoms from two 5-carb-oxy-1H-imidazole-4-carboxyl-ate ligands in trans positions, together with two water mol-ecules, completing a slightly distorted octahedral coordination. Inter-molecular N-H⋯O hydrogen bonding between the N-H group of the imidazole ring and the deprotonated carboxyl-ate group builds a chain of 5-carb-oxy-1H-imidazole-4-carboxyl-ate anions along the [101] direction. The water molecules form intermolecular hydrogen bonds to O-C and O=C sites of the carboxylate group in adjacent layers.

Related literature

For the structural diversity of the coordination architecture of the metal complexes of 4,5-n class="Chemical">imidazole­dicarb­oxy­lic acid, see Shimizu et al. (2004 ▶); Fang & Zhang (2006 ▶). For the isotypic Co analog, see: Li et al. (2011 ▶). For the coexisting phase, see Yakubovich et al. (1995 ▶). For the monoclinic form, see: Du et al. (2011 ▶).

Experimental

Crystal data

[Fe(C5H3N2O4)2(n class="Chemical">H2O)2]

M = 402.08

Triclinic,

a = 4.9290 (5) Å

b = 6.4258 (6) Å

c = 12.2812 (10) Å

α = 78.161 (3)°

β = 85.175 (3)°

γ = 72.776 (4)°

V = 363.52 (6) Å3

Z = 1

Mo Kα radiation

μ = 1.10 mm−1

T = 298 K

0.15 × 0.13 × 0.10 mm

Data collection

Rigaku R-AXIS RAPID diffractometer

Absorption correction: empirical (using intensity measurements) (ABSCOR; Higashi, 1995 ▶) T min = 0.852, T max = 0.898

3655 measured reflections

1668 independent reflections

1066 reflections with I > 2σ(I)

R int = 0.050

Refinement

R[F 2 > 2σ(F 2)] = 0.041

wR(F 2) = 0.075

S = 0.92

1668 reflections

122 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.30 e Å−3

Δρmin = −0.34 e Å−3

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812031753/fj2571sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812031753/fj2571Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812031753/fj2571Isup6.mol

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

[Fe(C5H3N2O4)2(H2O)2]	Z = 1
Mr = 402.08	F(000) = 204
Triclinic, P1	Dx = 1.837 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 4.9290 (5) Å	Cell parameters from 3918 reflections
b = 6.4258 (6) Å	θ = 3.4–30.5°
c = 12.2812 (10) Å	µ = 1.10 mm−1
α = 78.161 (3)°	T = 298 K
β = 85.175 (3)°	Block, yellow
γ = 72.776 (4)°	0.15 × 0.13 × 0.10 mm
V = 363.52 (6) Å3

Rigaku R-AXIS RAPID diffractometer	1668 independent reflections
Radiation source: fine-focus sealed tube	1066 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
Detector resolution: 100 pixels mm-1	θmax = 27.5°, θmin = 3.4°
ω scans	h = −6→6
Absorption correction: empirical (using intensity measurements) (ABSCOR; Higashi, 1995)	k = −8→8
Tmin = 0.852, Tmax = 0.898	l = −15→15
3655 measured reflections

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.075	H atoms treated by a mixture of independent and constrained refinement
S = 0.92	w = 1/[σ2(Fo2) + (0.0339P)2] where P = (Fo2 + 2Fc2)/3
1668 reflections	(Δ/σ)max < 0.001
122 parameters	Δρmax = 0.30 e Å−3
0 restraints	Δρmin = −0.34 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
Fe1	0.0000	0.0000	0.0000	0.0224 (2)
O5	0.3576 (5)	−0.2580 (4)	0.06771 (17)	0.0314 (5)
H1W	0.297 (7)	−0.370 (6)	0.097 (2)	0.047*
H2W	0.489 (7)	−0.278 (6)	0.026 (3)	0.047*
N1	0.1698 (5)	−0.0023 (4)	−0.16828 (18)	0.0237 (5)
C1	0.3247 (6)	0.0920 (5)	−0.2439 (2)	0.0262 (7)
H1	0.4099	0.1967	−0.2323	0.031*
N2	0.3439 (5)	0.0184 (4)	−0.33916 (18)	0.0277 (6)
H2A	0.4346	0.0598	−0.3986	0.033*
C2	0.1936 (6)	−0.1351 (5)	−0.3258 (2)	0.0233 (7)
C3	0.0869 (6)	−0.1468 (4)	−0.2178 (2)	0.0216 (6)
C4	0.1805 (6)	−0.2443 (5)	−0.4200 (2)	0.0279 (7)
O1	0.3050 (5)	−0.2040 (4)	−0.50906 (15)	0.0409 (6)
O2	0.0250 (6)	−0.3870 (4)	−0.40319 (18)	0.0551 (7)
H2	−0.0479	−0.3917	−0.3405	0.083*
C5	−0.0966 (6)	−0.2761 (5)	−0.1514 (2)	0.0236 (6)
O3	−0.1770 (4)	−0.4089 (3)	−0.19419 (15)	0.0328 (5)
O4	−0.1626 (4)	−0.2417 (3)	−0.05321 (14)	0.0262 (5)

	U11	U22	U33	U12	U13	U23
Fe1	0.0257 (4)	0.0281 (4)	0.0170 (3)	−0.0135 (3)	0.0060 (3)	−0.0062 (3)
O5	0.0304 (14)	0.0328 (14)	0.0320 (12)	−0.0157 (12)	0.0077 (9)	−0.0019 (10)
N1	0.0283 (14)	0.0267 (14)	0.0211 (11)	−0.0140 (12)	0.0014 (10)	−0.0070 (10)
C1	0.0309 (18)	0.0317 (18)	0.0225 (14)	−0.0184 (15)	0.0019 (13)	−0.0067 (13)
N2	0.0314 (15)	0.0371 (16)	0.0195 (11)	−0.0195 (13)	0.0077 (10)	−0.0058 (11)
C2	0.0284 (17)	0.0243 (17)	0.0194 (14)	−0.0103 (14)	0.0006 (12)	−0.0056 (12)
C3	0.0225 (16)	0.0235 (16)	0.0191 (13)	−0.0078 (14)	0.0012 (11)	−0.0034 (12)
C4	0.0343 (19)	0.0304 (18)	0.0244 (16)	−0.0168 (16)	0.0028 (13)	−0.0077 (13)
O1	0.0533 (16)	0.0563 (16)	0.0234 (11)	−0.0307 (14)	0.0124 (11)	−0.0134 (11)
O2	0.073 (2)	0.0626 (18)	0.0436 (14)	−0.0405 (16)	0.0158 (13)	−0.0184 (14)
C5	0.0250 (17)	0.0234 (17)	0.0239 (15)	−0.0083 (14)	−0.0014 (12)	−0.0052 (13)
O3	0.0458 (14)	0.0345 (13)	0.0281 (10)	−0.0261 (12)	0.0047 (10)	−0.0087 (9)
O4	0.0302 (12)	0.0313 (12)	0.0218 (10)	−0.0179 (11)	0.0088 (9)	−0.0057 (9)

Fe1—O5	2.121 (2)	C1—H1	0.9300
Fe1—O5i	2.121 (2)	N2—C2	1.377 (3)
Fe1—N1i	2.165 (2)	N2—H2A	0.8600
Fe1—N1	2.165 (2)	C2—C3	1.380 (3)
Fe1—O4i	2.1732 (16)	C2—C4	1.487 (3)
Fe1—O4	2.1732 (16)	C3—C5	1.489 (4)
O5—H1W	0.86 (3)	C4—O1	1.226 (3)
O5—H2W	0.79 (3)	C4—O2	1.335 (3)
N1—C1	1.317 (3)	O2—H2	0.8200
N1—C3	1.377 (3)	C5—O3	1.257 (3)
C1—N2	1.336 (3)	C5—O4	1.269 (3)
O5—Fe1—O5i	180.00 (11)	N1—C1—N2	111.5 (2)
O5—Fe1—N1i	87.70 (9)	N1—C1—H1	124.3
O5i—Fe1—N1i	92.30 (9)	N2—C1—H1	124.3
O5—Fe1—N1	92.30 (9)	C1—N2—C2	108.2 (2)
O5i—Fe1—N1	87.70 (9)	C1—N2—H2A	125.9
N1i—Fe1—N1	180.00 (16)	C2—N2—H2A	125.9
O5—Fe1—O4i	90.06 (7)	N2—C2—C3	105.0 (2)
O5i—Fe1—O4i	89.94 (7)	N2—C2—C4	119.4 (2)
N1i—Fe1—O4i	76.79 (7)	C3—C2—C4	135.6 (2)
N1—Fe1—O4i	103.21 (7)	N1—C3—C2	109.3 (2)
O5—Fe1—O4	89.94 (7)	N1—C3—C5	118.0 (2)
O5i—Fe1—O4	90.06 (7)	C2—C3—C5	132.7 (2)
N1i—Fe1—O4	103.21 (7)	O1—C4—O2	121.8 (2)
N1—Fe1—O4	76.79 (7)	O1—C4—C2	121.5 (2)
O4i—Fe1—O4	180.00 (12)	O2—C4—C2	116.7 (2)
Fe1—O5—H1W	107 (2)	C4—O2—H2	109.5
Fe1—O5—H2W	113 (3)	O3—C5—O4	124.3 (3)
H1W—O5—H2W	117 (3)	O3—C5—C3	119.6 (2)
C1—N1—C3	106.0 (2)	O4—C5—C3	116.1 (2)
C1—N1—Fe1	141.85 (18)	C5—O4—Fe1	116.99 (16)
C3—N1—Fe1	112.14 (17)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H1W···O3ii	0.86 (3)	1.86 (3)	2.705 (3)	165 (3)
O5—H2W···O4iii	0.79 (3)	1.95 (3)	2.702 (3)	158 (3)
N2—H2A···O1iv	0.86	1.95	2.767 (3)	157
O2—H2···O3	0.82	1.85	2.665 (3)	174

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H1W⋯O3i	0.86 (3)	1.86 (3)	2.705 (3)	165 (3)
O5—H2W⋯O4ii	0.79 (3)	1.95 (3)	2.702 (3)	158 (3)
N2—H2A⋯O1iii	0.86	1.95	2.767 (3)	157
O2—H2⋯O3	0.82	1.85	2.665 (3)	174

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