catena-Poly[[(pyrimidine-2-carb­oxy­lic acid)iron(II)]-μ-oxalato]

In the title complex, [Fe(C₂O₄)(C₅H₄N₂O₄)]_n, the Fe^II ion is coordinated by two oxalate anions and a pyrimidine-2-carb­oxy­lic acid ligand in a slightly distorted octa­hedral geometry. Each oxalate anion chelates to two Fe^II ions, forming chains along the a axis. The chains are further connected by O—H...O and C—H...O hydrogen bonds, stabilizing the structure. An intra­molecular O—H...N inter­action results in a five-membered ring.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.040
• wR factor = 0.083
• Data-to-parameter ratio = 11.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for    O6     --  C3      ..       6.65 su
PLAT341_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..          7
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.01
           From the CIF: _reflns_number_total               1658
           Count of symmetry unique reflns          876
           Completeness (_total/calc)            189.27%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       782
           Fraction of Friedel pairs measured     0.893
           Are heavy atom types Z>Si present        yes
PLAT917_ALERT_2_G The FCF is likely NOT based on a BASF/TWIN Flack          !
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K

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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Pyrimidine-2-carboxylic acid (HL) and oxalate anion have similar coordination mode, acting as bidentate ligands, and some Cd complexes have been reported containing both ligands (Zhang et al., 2008). Here we report the synthesis and crystal structure of a new iron complex with pyrimidine-2-carboxylic acid and oxalate as co-ligands.

In the title complex, the Fe^II ions are coordinated by one HL ligand and two oxalate anions in a slightly distorted octahedral geometry (Fig. 1). Each oxalate anion chelates to two Fe^II ions resulting a chain along the a-axis. There is an intramolecular interaction O6—H6···N2 resulting in a five membererd ring. The O—H···O and C—H···O type hydrogen bonds between the oxalate and HL ligands impart stability to the structure (Fig. 2).

Related literature

For related structures, see: Zhang et al. (2008).

S2. Experimental

A mixture of Fe(III) chloride (2 mmol), oxalate acid (2 mmol)and pyrimidine-2-carbonitrile (1 mmol), in 10 ml dimethyl formamate (DMF) solvent was sealed in a Teflon-lined stainless-steel Parr bomb was heated at 413 K for 48 h. Red crystals of the title complex were collected after the bomb was allowed to cool to room temperature; yield 20%.

S3. Refinement

The absolute structure of the title complex was determined by the Flack (1983) method. Hydrogen atoms were included in calculated positions and treated as riding on their parent atoms with O—H and C—H = 0.85 and 0.93 Å, respectively and U_iso(H) = 1.2U_eq(O/C).

Computing details

Data collection: SCXmini Benchtop Crystallography System Software (Rigaku, 2006); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: PROCESS-AUTO (Rigaku, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The coordinated mode and linkage of the complex. Ellipsoids are drawn at the 30% probability level. Symmetry codes: i = x+1/2,-y-1/2,z ii= x-1/2,-y-1/2,z
	Fig. 2. A partial packing diagram of the unit cell viewed down the c-axis.

catena-Poly[[(pyrimidine-2-carboxylic acid)iron(II)]-µ-oxalato]

Crystal data

[Fe(C2O4)(C5H4N2O4)]	F(000) = 536
Mr = 267.97	Dx = 1.895 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 8691 reflections
a = 9.0524 (18) Å	θ = 3.2–27.5°
b = 9.1578 (18) Å	µ = 1.62 mm^−1
c = 11.329 (2) Å	T = 293 K
V = 939.2 (3) Å^3	Block, red
Z = 4	0.2 × 0.18 × 0.16 mm

Data collection

Rigaku SCXmini diffractometer	1658 independent reflections
Radiation source: fine-focus sealed tube	1503 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.074
ω scans	θmax = 25.0°, θmin = 3.2°
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	h = −10→10
Tmin = 0.780, Tmax = 1	k = −10→10
7603 measured reflections	l = −13→13

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)] = 0.040	H-atom parameters constrained
wR(F^2) = 0.083	w = 1/[σ^2(Fo^2) + (0.0339P)^2 + 0.7762P] where P = (Fo^2 + 2Fc^2)/3
S = 1.11	(Δ/σ)max = 0.001
1658 reflections	Δρmax = 0.46 e Å^−3
145 parameters	Δρmin = −0.30 e Å^−3
1 restraint	Absolute structure: Flack (1983), 783 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.05 (3)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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
Fe1	0.13566 (6)	−0.08170 (6)	0.71653 (7)	0.02969 (18)
C4	0.1749 (5)	0.2409 (5)	0.7015 (4)	0.0263 (10)
O5	0.2520 (4)	0.0586 (3)	0.8376 (3)	0.0397 (9)
O1	−0.0702 (3)	−0.0924 (3)	0.8009 (3)	0.0293 (7)
N1	0.0989 (4)	0.1349 (4)	0.6452 (4)	0.0307 (9)
O6	0.3406 (5)	0.2878 (5)	0.8630 (4)	0.0624 (12)
H6	0.3456	0.3746	0.8369	0.075*
C3	0.2601 (5)	0.1886 (5)	0.8074 (4)	0.0325 (11)
O3	−0.2731 (3)	−0.2329 (4)	0.8046 (3)	0.0353 (8)
O2	0.0098 (4)	−0.2138 (4)	0.5963 (3)	0.0343 (8)
C7	0.0149 (5)	0.1768 (6)	0.5565 (4)	0.0349 (12)
H7A	−0.0405	0.1072	0.5163	0.042*
O4	−0.1781 (4)	−0.3696 (4)	0.6089 (3)	0.0368 (9)
C5	0.0923 (6)	0.4168 (6)	0.5831 (5)	0.0438 (13)
H5A	0.0916	0.5141	0.5597	0.053*
C6	0.0066 (6)	0.3211 (6)	0.5216 (5)	0.0408 (13)
H6A	−0.0539	0.3511	0.4598	0.049*
N2	0.1764 (5)	0.3806 (4)	0.6738 (4)	0.0350 (11)
C2	−0.1034 (5)	−0.2649 (5)	0.6452 (4)	0.0263 (11)
C1	−0.1539 (5)	−0.1906 (5)	0.7602 (4)	0.0256 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Fe1	0.0248 (3)	0.0246 (3)	0.0396 (4)	−0.0008 (3)	0.0015 (4)	0.0021 (4)
C4	0.028 (2)	0.028 (2)	0.023 (3)	0.0011 (17)	0.002 (2)	−0.002 (2)
O5	0.053 (2)	0.0245 (19)	0.042 (2)	−0.0094 (17)	−0.0203 (18)	0.0093 (15)
O1	0.0252 (17)	0.0282 (17)	0.0344 (19)	0.0003 (15)	0.0030 (15)	−0.0040 (15)
N1	0.030 (2)	0.034 (2)	0.029 (2)	0.0011 (18)	0.0004 (18)	0.0003 (18)
O6	0.076 (3)	0.049 (3)	0.062 (3)	−0.010 (2)	−0.010 (2)	0.007 (2)
C3	0.033 (3)	0.035 (3)	0.029 (3)	−0.007 (2)	−0.006 (2)	−0.001 (2)
O3	0.0304 (19)	0.0338 (19)	0.042 (2)	−0.0084 (16)	0.0102 (17)	−0.0078 (17)
O2	0.0298 (18)	0.0426 (19)	0.0304 (18)	−0.0060 (16)	0.0071 (16)	−0.0054 (17)
C7	0.033 (3)	0.042 (3)	0.030 (3)	−0.002 (2)	−0.007 (2)	−0.003 (2)
O4	0.0292 (18)	0.041 (2)	0.040 (2)	−0.0042 (16)	0.0069 (17)	−0.0142 (17)
C5	0.053 (3)	0.033 (3)	0.045 (3)	0.010 (3)	−0.001 (3)	0.008 (3)
C6	0.043 (3)	0.043 (3)	0.037 (3)	0.010 (3)	−0.008 (3)	0.002 (2)
N2	0.041 (3)	0.024 (2)	0.039 (3)	−0.0041 (17)	−0.0069 (19)	0.0036 (16)
C2	0.023 (2)	0.030 (3)	0.026 (3)	0.007 (2)	−0.001 (2)	−0.001 (2)
C1	0.021 (2)	0.024 (2)	0.032 (2)	0.003 (2)	0.0027 (19)	0.0036 (18)

Geometric parameters (Å, º)

Fe1—O1	2.097 (3)	O6—H6	0.8500
Fe1—O4^i	2.128 (3)	O3—C1	1.252 (5)
Fe1—O3^i	2.136 (3)	O3—Fe1^ii	2.136 (3)
Fe1—O2	2.148 (3)	O2—C2	1.255 (6)
Fe1—O5	2.154 (3)	C7—C6	1.382 (7)
Fe1—N1	2.168 (4)	C7—H7A	0.9300
C4—N2	1.318 (6)	O4—C2	1.243 (6)
C4—N1	1.350 (6)	O4—Fe1^ii	2.128 (3)
C4—C3	1.504 (7)	C5—N2	1.321 (7)
O5—C3	1.240 (6)	C5—C6	1.362 (8)
O1—C1	1.263 (6)	C5—H5A	0.9300
N1—C7	1.317 (6)	C6—H6A	0.9300
O6—C3	1.325 (6)	C2—C1	1.540 (6)
O1—Fe1—O4^i	162.87 (14)	C3—O6—H6	120.4
O1—Fe1—O3^i	95.38 (13)	O5—C3—O6	124.0 (4)
O4^i—Fe1—O3^i	78.16 (13)	O5—C3—C4	119.7 (4)
O1—Fe1—O2	77.96 (12)	O6—C3—C4	116.3 (4)
O4^i—Fe1—O2	86.49 (14)	C1—O3—Fe1^ii	113.1 (3)
O3^i—Fe1—O2	93.08 (14)	C2—O2—Fe1	111.3 (3)
O1—Fe1—O5	99.90 (14)	N1—C7—C6	121.9 (5)
O4^i—Fe1—O5	95.90 (15)	N1—C7—H7A	119.1
O3^i—Fe1—O5	89.29 (13)	C6—C7—H7A	119.1
O2—Fe1—O5	176.94 (13)	C2—O4—Fe1^ii	113.7 (3)
O1—Fe1—N1	94.37 (14)	N2—C5—C6	124.4 (5)
O4^i—Fe1—N1	95.72 (14)	N2—C5—H5A	117.8
O3^i—Fe1—N1	163.96 (15)	C6—C5—H5A	117.8
O2—Fe1—N1	101.40 (14)	C5—C6—C7	115.9 (5)
O5—Fe1—N1	76.50 (14)	C5—C6—H6A	122.0
N2—C4—N1	126.2 (5)	C7—C6—H6A	122.0
N2—C4—C3	119.6 (4)	C4—N2—C5	115.0 (4)
N1—C4—C3	114.2 (4)	O4—C2—O2	125.8 (5)
C3—O5—Fe1	115.2 (3)	O4—C2—C1	117.4 (4)
C1—O1—Fe1	113.6 (3)	O2—C2—C1	116.8 (4)
C7—N1—C4	116.5 (4)	O3—C1—O1	126.2 (4)
C7—N1—Fe1	129.7 (4)	O3—C1—C2	117.3 (4)
C4—N1—Fe1	113.8 (3)	O1—C1—C2	116.5 (4)
O1—Fe1—O5—C3	−99.7 (4)	N1—C4—C3—O5	−2.3 (6)
O4^i—Fe1—O5—C3	86.9 (4)	N2—C4—C3—O6	−4.2 (7)
O3^i—Fe1—O5—C3	165.0 (4)	N1—C4—C3—O6	177.7 (4)
N1—Fe1—O5—C3	−7.5 (4)	O1—Fe1—O2—C2	−17.7 (3)
O4^i—Fe1—O1—C1	−10.5 (6)	O4^i—Fe1—O2—C2	155.1 (3)
O3^i—Fe1—O1—C1	−77.3 (3)	O3^i—Fe1—O2—C2	77.2 (3)
O2—Fe1—O1—C1	14.7 (3)	N1—Fe1—O2—C2	−109.8 (3)
O5—Fe1—O1—C1	−167.5 (3)	C4—N1—C7—C6	1.0 (7)
N1—Fe1—O1—C1	115.5 (3)	Fe1—N1—C7—C6	−178.9 (4)
N2—C4—N1—C7	−2.3 (7)	N2—C5—C6—C7	−2.2 (9)
C3—C4—N1—C7	175.7 (4)	N1—C7—C6—C5	1.0 (8)
N2—C4—N1—Fe1	177.7 (4)	N1—C4—N2—C5	1.2 (7)
C3—C4—N1—Fe1	−4.3 (5)	C3—C4—N2—C5	−176.7 (4)
O1—Fe1—N1—C7	−74.8 (4)	C6—C5—N2—C4	1.2 (8)
O4^i—Fe1—N1—C7	91.3 (4)	Fe1^ii—O4—C2—O2	−178.8 (4)
O3^i—Fe1—N1—C7	157.9 (5)	Fe1^ii—O4—C2—C1	1.0 (5)
O2—Fe1—N1—C7	3.8 (4)	Fe1—O2—C2—O4	−162.4 (4)
O5—Fe1—N1—C7	−174.0 (4)	Fe1—O2—C2—C1	17.8 (5)
O1—Fe1—N1—C4	105.3 (3)	Fe1^ii—O3—C1—O1	−173.3 (4)
O4^i—Fe1—N1—C4	−88.6 (3)	Fe1^ii—O3—C1—C2	6.6 (5)
O3^i—Fe1—N1—C4	−22.1 (7)	Fe1—O1—C1—O3	169.6 (4)
O2—Fe1—N1—C4	−176.2 (3)	Fe1—O1—C1—C2	−10.3 (5)
O5—Fe1—N1—C4	6.1 (3)	O4—C2—C1—O3	−5.4 (6)
Fe1—O5—C3—O6	−172.2 (4)	O2—C2—C1—O3	174.4 (4)
Fe1—O5—C3—C4	7.8 (6)	O4—C2—C1—O1	174.4 (4)
N2—C4—C3—O5	175.8 (5)	O2—C2—C1—O1	−5.7 (6)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6A···O3^iii	0.93	2.48	3.279 (6)	145
O6—H6···O1^iv	0.85	2.17	2.988 (5)	161
O6—H6···N2	0.85	2.40	2.743 (6)	105

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