Diaqua­bis(5-carb­oxy-2-methyl-1H-imid­azole-4-carboxyl­ato-κ²N³,O⁴)cadmium(II)

In the title compound, [Cd(C₆H₇N₂O₅)₂], the Cd atom lies on an inversion center and has a slightly distorted octa­hedral geometry. The equatorial plane contains two bidentate 5-carb­oxy-2-methyl-1H-imidazole-4-carboxyl­ate monoanionic ligands. Two coordinated water mol­ecules occupy the axial sites. Inter­molecular N—H...O hydrogen bonds link the mol­ecules into chains, which are further connected by inter­molecular O—H...O hydrogen bonds, resulting in a three-dimensional supra­molecular framework.

Key indicators

• Single-crystal X-ray study
• T = 113 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.021
• wR factor = 0.058
• Data-to-parameter ratio = 14.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       3.72

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

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

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Computing details

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg & Berndt, 2005); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2005).

diaquabis[5-carboxy-2-methyl-1H-imidazole-4-carboxylato- κ²N³,O⁴]cadmium(II)

Crystal data

[Cd(C6H7N2O5)2]	F(000) = 484
Mr = 486.67	Dx = 1.975 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71070 Å
Hall symbol: -P 2ybc	Cell parameters from 2435 reflections
a = 12.0540 (14) Å	θ = 2.2–27.9°
b = 9.2501 (12) Å	µ = 1.40 mm^−1
c = 7.4506 (10) Å	T = 113 K
β = 99.957 (6)°	Block, colorless
V = 818.23 (18) Å^3	0.32 × 0.10 × 0.08 mm
Z = 2

Data collection

Rigaku Saturn diffractometer	1929 independent reflections
Radiation source: rotating anode	1605 reflections with I > 2σ (I)
Confocal monochromator	Rint = 0.036
Detector resolution: 7.31 pixels mm^-1	θmax = 27.9°, θmin = 2.8°
ω scans	h = −15→15
Absorption correction: numerical (Jacobson, 1998)	k = −12→12
Tmin = 0.663, Tmax = 0.896	l = −9→9
9684 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.021	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.059	w = 1/[σ^2(Fo^2) + (0.0365P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.002
1929 reflections	Δρmax = 1.55 e Å^−3
136 parameters	Δρmin = −0.42 e Å^−3
4 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: 0.033 (2)

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
Cd1	0.5000	0.5000	1.0000	0.00937 (10)
O1	0.43259 (9)	0.26469 (12)	1.01015 (15)	0.0129 (3)
O2	0.29496 (9)	0.11477 (13)	0.88841 (15)	0.0133 (3)
O3	0.10072 (10)	0.12804 (14)	0.69348 (18)	0.0195 (3)
H3	0.1627 (15)	0.113 (2)	0.761 (3)	0.023*
O4	−0.00625 (10)	0.30220 (16)	0.5515 (2)	0.0226 (3)
O5	0.46972 (12)	0.53924 (16)	1.28686 (18)	0.0182 (3)
H5A	0.4174 (19)	0.4970 (17)	1.334 (4)	0.022*
H5B	0.5029 (15)	0.603 (2)	1.355 (2)	0.022*
N1	0.31039 (15)	0.50408 (12)	0.8737 (2)	0.0106 (3)
N2	0.14321 (16)	0.51737 (15)	0.7025 (3)	0.0137 (4)
H2	0.0868	0.5508	0.6360	0.016*
C1	0.23308 (14)	0.59308 (19)	0.7858 (2)	0.0128 (4)
C2	0.26811 (14)	0.36681 (19)	0.8445 (2)	0.0104 (3)
C3	0.16232 (13)	0.37380 (19)	0.7361 (2)	0.0112 (3)
C4	0.24189 (15)	0.75314 (18)	0.7767 (3)	0.0195 (4)
H4A	0.3084	0.7792	0.7244	0.029*
H4B	0.2489	0.7937	0.8997	0.029*
H4C	0.1742	0.7920	0.7000	0.029*
C5	0.33632 (14)	0.24015 (18)	0.9195 (2)	0.0110 (3)
C6	0.07894 (14)	0.26467 (19)	0.6537 (2)	0.0154 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.00841 (13)	0.01057 (13)	0.00812 (13)	−0.00017 (5)	−0.00144 (8)	−0.00048 (5)
O1	0.0115 (6)	0.0120 (6)	0.0133 (6)	0.0000 (5)	−0.0034 (5)	0.0015 (5)
O2	0.0129 (6)	0.0101 (6)	0.0162 (6)	−0.0009 (5)	0.0007 (5)	0.0001 (5)
O3	0.0132 (6)	0.0179 (7)	0.0242 (7)	−0.0021 (5)	−0.0058 (5)	0.0019 (5)
O4	0.0150 (7)	0.0228 (8)	0.0253 (7)	−0.0018 (5)	−0.0095 (5)	0.0041 (6)
O5	0.0212 (8)	0.0221 (7)	0.0121 (7)	−0.0120 (6)	0.0048 (6)	−0.0080 (6)
N1	0.0093 (9)	0.0125 (8)	0.0098 (8)	0.0008 (5)	0.0009 (7)	0.0004 (5)
N2	0.0097 (8)	0.0147 (8)	0.0151 (9)	0.0019 (5)	−0.0021 (7)	0.0028 (6)
C1	0.0094 (8)	0.0164 (9)	0.0124 (8)	0.0018 (7)	0.0010 (7)	0.0008 (7)
C2	0.0100 (8)	0.0131 (8)	0.0081 (7)	−0.0005 (7)	0.0013 (6)	−0.0001 (6)
C3	0.0087 (8)	0.0137 (9)	0.0112 (8)	0.0004 (7)	0.0012 (6)	0.0010 (6)
C4	0.0195 (9)	0.0132 (9)	0.0244 (10)	0.0019 (7)	−0.0003 (8)	0.0026 (8)
C5	0.0123 (8)	0.0132 (8)	0.0080 (7)	0.0010 (6)	0.0031 (6)	−0.0002 (6)
C6	0.0128 (8)	0.0179 (9)	0.0151 (8)	−0.0019 (7)	0.0010 (7)	0.0010 (7)

Geometric parameters (Å, º)

Cd1—O5^i	2.2589 (14)	N1—C1	1.328 (2)
Cd1—O5	2.2589 (14)	N1—C2	1.372 (2)
Cd1—N1^i	2.3167 (18)	N2—C1	1.348 (2)
Cd1—N1	2.3167 (18)	N2—C3	1.364 (2)
Cd1—O1	2.3292 (12)	N2—H2	0.8287
Cd1—O1^i	2.3292 (12)	C1—C4	1.487 (2)
O1—C5	1.2582 (19)	C2—C3	1.388 (2)
O2—C5	1.268 (2)	C2—C5	1.484 (2)
O3—C6	1.314 (2)	C3—C6	1.481 (2)
O3—H3	0.836 (17)	C4—H4A	0.9800
O4—C6	1.218 (2)	C4—H4B	0.9800
O5—H5A	0.87 (2)	C4—H4C	0.9800
O5—H5B	0.833 (16)
O5^i—Cd1—O5	180.0	C1—N2—H2	126.4
O5^i—Cd1—N1^i	94.15 (6)	C3—N2—H2	124.6
O5—Cd1—N1^i	85.86 (6)	N1—C1—N2	110.16 (16)
O5^i—Cd1—N1	85.85 (6)	N1—C1—C4	126.18 (16)
O5—Cd1—N1	94.14 (6)	N2—C1—C4	123.66 (15)
N1^i—Cd1—N1	180.0	N1—C2—C3	109.15 (15)
O5^i—Cd1—O1	89.71 (5)	N1—C2—C5	120.31 (15)
O5—Cd1—O1	90.29 (5)	C3—C2—C5	130.50 (16)
N1^i—Cd1—O1	107.27 (4)	N2—C3—C2	105.15 (15)
N1—Cd1—O1	72.73 (4)	N2—C3—C6	120.43 (15)
O5^i—Cd1—O1^i	90.29 (5)	C2—C3—C6	134.35 (16)
O5—Cd1—O1^i	89.71 (5)	C1—C4—H4A	109.5
N1^i—Cd1—O1^i	72.73 (4)	C1—C4—H4B	109.5
N1—Cd1—O1^i	107.27 (4)	H4A—C4—H4B	109.5
O1—Cd1—O1^i	180.0	C1—C4—H4C	109.5
C5—O1—Cd1	116.47 (10)	H4A—C4—H4C	109.5
C6—O3—H3	114.9 (15)	H4B—C4—H4C	109.5
Cd1—O5—H5A	124.0 (17)	O1—C5—O2	124.06 (15)
Cd1—O5—H5B	123.4 (13)	O1—C5—C2	117.34 (15)
H5A—O5—H5B	112.3 (18)	O2—C5—C2	118.59 (14)
C1—N1—C2	106.61 (15)	O4—C6—O3	121.94 (16)
C1—N1—Cd1	140.28 (12)	O4—C6—C3	120.22 (16)
C2—N1—Cd1	111.27 (11)	O3—C6—C3	117.84 (15)
C1—N2—C3	108.93 (15)
O5^i—Cd1—O1—C5	−73.79 (11)	Cd1—N1—C2—C3	−167.92 (11)
O5—Cd1—O1—C5	106.20 (11)	C1—N1—C2—C5	177.78 (14)
N1^i—Cd1—O1—C5	−168.04 (11)	Cd1—N1—C2—C5	9.9 (2)
N1—Cd1—O1—C5	11.95 (11)	C1—N2—C3—C2	0.2 (2)
O5^i—Cd1—N1—C1	−81.3 (2)	C1—N2—C3—C6	−177.27 (15)
O5—Cd1—N1—C1	98.7 (2)	N1—C2—C3—N2	−0.1 (2)
O1—Cd1—N1—C1	−172.3 (2)	C5—C2—C3—N2	−177.63 (17)
O1^i—Cd1—N1—C1	7.7 (2)	N1—C2—C3—C6	176.86 (18)
O5^i—Cd1—N1—C2	80.31 (13)	C5—C2—C3—C6	−0.7 (3)
O5—Cd1—N1—C2	−99.69 (13)	Cd1—O1—C5—O2	168.90 (12)
O1—Cd1—N1—C2	−10.67 (12)	Cd1—O1—C5—C2	−10.84 (18)
O1^i—Cd1—N1—C2	169.33 (12)	N1—C2—C5—O1	0.4 (2)
C2—N1—C1—N2	0.2 (2)	C3—C2—C5—O1	177.72 (17)
Cd1—N1—C1—N2	162.30 (16)	N1—C2—C5—O2	−179.38 (16)
C2—N1—C1—C4	−179.38 (15)	C3—C2—C5—O2	−2.0 (3)
Cd1—N1—C1—C4	−17.3 (3)	N2—C3—C6—O4	1.8 (3)
C3—N2—C1—N1	−0.2 (2)	C2—C3—C6—O4	−174.79 (19)
C3—N2—C1—C4	179.35 (16)	N2—C3—C6—O3	−178.76 (16)
C1—N1—C2—C3	−0.1 (2)	C2—C3—C6—O3	4.7 (3)

Symmetry code: (i) −x+1, −y+1, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O4^ii	0.83	2.07	2.830 (2)	153
O5—H5B···O1^iii	0.83 (2)	1.89 (2)	2.7216 (17)	173 (2)
O5—H5A···O2^iv	0.87 (2)	1.90 (2)	2.7551 (19)	168 (2)
O3—H3···O2	0.84 (2)	1.71 (2)	2.5358 (16)	169 (2)

Symmetry codes: (ii) −x, −y+1, −z+1; (iii) −x+1, y+1/2, −z+5/2; (iv) x, −y+1/2, z+1/2.