Diaqua­(5-methyl­pyrazine-2-carboxyl­ato-κ² N ¹,O)iron(II)

Abstract

In the neutral title complex, [Fe(C₆H₅N₂O₂)₂(H₂O)₂], the coordination geometry aound the Fe^II atom, which lies on an inversion centre, is distorted octa­hedral comprising two N atoms and two O atoms from two 5-methyl­pyrazine-2-carboxyl­ate ligands, and two water mol­ecules. The crystal structure is stabilized by a network of O—H⋯O hydrogen bonds, resulting in a two-dimensional supra­molecular structure.

Related literature

For background to this study, see: Fan et al. (2007 ▶).

Experimental

Crystal data

• [Fe(C₆H₅N₂O₂)₂(H₂O)₂]

• M _r = 366.12

• Triclinic,

• a = 5.068 (1) Å

• b = 6.401 (1) Å

• c = 12.381 (1) Å

• α = 103.851 (2)°

• β = 91.790(10)°

• γ = 108.340 (2)°

• V = 368.22 (10) ų

• Z = 1

• Mo Kα radiation

• μ = 1.06 mm⁻¹

• T = 298 (2) K

• 0.18 × 0.09 × 0.05 mm

Data collection

• Bruker SMART CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.832, T _max = 0.949

• 1916 measured reflections

• 1260 independent reflections

• 1061 reflections with I > 2σ(I)

• R _int = 0.025

Refinement

• R[F ² > 2σ(F ²)] = 0.041

• wR(F ²) = 0.095

• S = 1.00

• 1260 reflections

• 107 parameters

• H-atom parameters constrained

• Δρ_max = 0.33 e Å⁻³

• Δρ_min = −0.28 e Å⁻³

Data collection: SMART (Bruker, 2002 ▶); cell refinement: SAINT (Bruker, 2002 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3A⋯O1i	0.85	1.93	2.720 (3)	155
O3—H3B⋯O2ii	0.85	1.86	2.673 (3)	159

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

The background to this study is set out in the preceding paper (Fan et al., 2007). Here we report the crystal structure of a mononuclear Fe^II (Fig. 1).

The asymmetric unit consists of a Fe^II atom, which lies on an inversion centre, one 2mpac ligand and two water molecules. A ring nitrogen atom and an oxygen atom of the carboxylate group from 2mpac ligand with Fe1—O1 = 2.103 (2) Å and Fe1—N1 = 2.167 (3) Å are involved in coordination to the Fe^II atom; these form a square. The coordination of the two water molecules with Fe1—O3 = 2.114 (2) Å occupied the axial sites results in the formation of a distorted octahedral geometry.

In the crystal structure, hydrogen bonding interactions are observed between the hydrogen atoms of the coordinated water molecules and the oxygen atoms of the carboxyl groups of a neighbouring unit, affording a two-dimensional supramolecular structure (Figure 2).

Experimental

The title compound was obtained from the mixture of ferrous ammonium sulfate hexahydrate(0.10 g, 0.25 mmol), 5-methylpyrazine-2-carboxylic acid (0.70 g, 0.5 mmol) and distilled water (20 ml), which was placed at room temperature for two weeks and red single crystals were obtained finally.

Refinement

All H atoms attached to C atoms from the organic ligands were generated in idealized positions and constrained to ride on their parent atoms, with d(C—H) = 0.93 Å, U_iso=1.2U_eq (C) for aromatic and 0.96 Å, U_iso = 1.5U_eq (C) for CH₃ atoms.

Figures

Fig. 1.

A view of the molecular structure of title complex with the atom-labling scheme. Displacement ellipsoids are drawn at the 30% probability level. Symmetry code for A: 1-X, 1-Y, 1-Z.

Fig. 2.

Two-dimensional supramolecular structure of the title complex.

Crystal data

[Fe(C6H5N2O2)2(H2O)2]	Z = 1
Mr = 366.12	F(000) = 188
Triclinic, P1	Dx = 1.651 Mg m−3
a = 5.068 (1) Å	Mo Kα radiation, λ = 0.71073 Å
b = 6.401 (1) Å	Cell parameters from 715 reflections
c = 12.3810 (12) Å	θ = 3.4–26.8°
α = 103.851 (2)°	µ = 1.06 mm−1
β = 91.079 (1)°	T = 298 K
γ = 108.340 (2)°	Block, red
V = 368.22 (10) Å3	0.18 × 0.09 × 0.05 mm

Data collection

Bruker SMART CCD area-detector diffractometer	1260 independent reflections
Radiation source: fine-focus sealed tube	1061 reflections with I > 2σ(I)
graphite	Rint = 0.025
φ and ω scans	θmax = 25.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→6
Tmin = 0.832, Tmax = 0.949	k = −7→7
1916 measured reflections	l = −14→12

Refinement

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) = 0.095	H-atom parameters constrained
S = 1.00	w = 1/[σ2(Fo2) + (0.0456P)2] where P = (Fo2 + 2Fc2)/3
1260 reflections	(Δ/σ)max < 0.001
107 parameters	Δρmax = 0.33 e Å−3
0 restraints	Δρmin = −0.28 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
Fe1	0.5000	0.5000	0.5000	0.0326 (3)
N1	0.5923 (6)	0.4742 (4)	0.3281 (2)	0.0323 (7)
N2	0.6791 (7)	0.4921 (6)	0.1096 (2)	0.0508 (8)
O1	0.3162 (5)	0.7203 (4)	0.45178 (18)	0.0359 (6)
O2	0.2550 (5)	0.8729 (4)	0.3133 (2)	0.0472 (7)
O3	0.8721 (5)	0.7772 (4)	0.56033 (19)	0.0423 (6)
H3A	1.0121	0.7975	0.5226	0.051*
H3B	0.8701	0.9077	0.5961	0.051*
C1	0.3463 (7)	0.7489 (5)	0.3543 (3)	0.0330 (8)
C2	0.5049 (7)	0.6138 (5)	0.2826 (3)	0.0313 (8)
C3	0.5494 (8)	0.6191 (7)	0.1744 (3)	0.0482 (10)
H3	0.4856	0.7167	0.1445	0.058*
C4	0.7211 (7)	0.3461 (6)	0.2642 (3)	0.0360 (8)
H4	0.7855	0.2487	0.2940	0.043*
C5	0.7624 (7)	0.3530 (6)	0.1548 (3)	0.0394 (8)
C6	0.9003 (9)	0.2011 (7)	0.0829 (3)	0.0582 (11)
H6A	0.7600	0.0722	0.0347	0.087*
H6B	1.0059	0.1495	0.1297	0.087*
H6C	1.0232	0.2847	0.0384	0.087*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Fe1	0.0405 (5)	0.0352 (4)	0.0282 (4)	0.0197 (3)	0.0122 (3)	0.0092 (3)
N1	0.0366 (16)	0.0321 (16)	0.0329 (15)	0.0170 (13)	0.0109 (12)	0.0089 (13)
N2	0.064 (2)	0.068 (2)	0.0329 (17)	0.0347 (19)	0.0192 (15)	0.0171 (17)
O1	0.0419 (14)	0.0395 (14)	0.0356 (14)	0.0238 (11)	0.0170 (10)	0.0118 (11)
O2	0.0649 (18)	0.0445 (16)	0.0469 (15)	0.0355 (14)	0.0114 (12)	0.0151 (13)
O3	0.0427 (15)	0.0346 (14)	0.0527 (16)	0.0186 (12)	0.0178 (11)	0.0082 (12)
C1	0.0330 (19)	0.0275 (18)	0.037 (2)	0.0099 (15)	0.0054 (14)	0.0044 (15)
C2	0.0337 (19)	0.0296 (18)	0.0322 (19)	0.0137 (15)	0.0061 (14)	0.0066 (15)
C3	0.063 (3)	0.059 (3)	0.038 (2)	0.035 (2)	0.0160 (18)	0.020 (2)
C4	0.039 (2)	0.037 (2)	0.039 (2)	0.0206 (16)	0.0122 (16)	0.0104 (16)
C5	0.038 (2)	0.047 (2)	0.0333 (19)	0.0198 (17)	0.0102 (15)	0.0036 (17)
C6	0.065 (3)	0.063 (3)	0.047 (2)	0.030 (2)	0.019 (2)	−0.001 (2)

Geometric parameters (Å, °)

Fe1—O1i	2.103 (2)	O3—H3A	0.8500
Fe1—O1	2.103 (2)	O3—H3B	0.8499
Fe1—O3i	2.114 (2)	C1—C2	1.510 (5)
Fe1—O3	2.114 (2)	C2—C3	1.369 (5)
Fe1—N1i	2.167 (3)	C3—H3	0.9300
Fe1—N1	2.167 (3)	C4—C5	1.384 (5)
N1—C4	1.331 (4)	C4—H4	0.9300
N1—C2	1.339 (4)	C5—C6	1.505 (5)
N2—C5	1.323 (4)	C6—H6A	0.9600
N2—C3	1.335 (5)	C6—H6B	0.9600
O1—C1	1.268 (4)	C6—H6C	0.9600
O2—C1	1.232 (4)
O1i—Fe1—O1	180.00 (11)	H3A—O3—H3B	107.6
O1i—Fe1—O3i	89.75 (9)	O2—C1—O1	126.0 (3)
O1—Fe1—O3i	90.25 (9)	O2—C1—C2	117.9 (3)
O1i—Fe1—O3	90.25 (9)	O1—C1—C2	116.0 (3)
O1—Fe1—O3	89.75 (9)	N1—C2—C3	119.7 (3)
O3i—Fe1—O3	180.00 (10)	N1—C2—C1	116.5 (3)
O1i—Fe1—N1i	77.21 (9)	C3—C2—C1	123.7 (3)
O1—Fe1—N1i	102.79 (9)	N2—C3—C2	123.6 (3)
O3i—Fe1—N1i	92.02 (9)	N2—C3—H3	118.2
O3—Fe1—N1i	87.98 (9)	C2—C3—H3	118.2
O1i—Fe1—N1	102.79 (9)	N1—C4—C5	122.1 (3)
O1—Fe1—N1	77.21 (9)	N1—C4—H4	118.9
O3i—Fe1—N1	87.98 (9)	C5—C4—H4	118.9
O3—Fe1—N1	92.02 (9)	N2—C5—C4	121.0 (3)
N1i—Fe1—N1	180.000 (1)	N2—C5—C6	117.8 (3)
C4—N1—C2	117.2 (3)	C4—C5—C6	121.2 (3)
C4—N1—Fe1	130.3 (2)	C5—C6—H6A	109.5
C2—N1—Fe1	112.5 (2)	C5—C6—H6B	109.5
C5—N2—C3	116.3 (3)	H6A—C6—H6B	109.5
C1—O1—Fe1	117.6 (2)	C5—C6—H6C	109.5
Fe1—O3—H3A	121.1	H6A—C6—H6C	109.5
Fe1—O3—H3B	121.9	H6B—C6—H6C	109.5
O1i—Fe1—N1—C4	2.7 (3)	C4—N1—C2—C3	0.2 (5)
O1—Fe1—N1—C4	−177.3 (3)	Fe1—N1—C2—C3	179.5 (3)
O3i—Fe1—N1—C4	−86.6 (3)	C4—N1—C2—C1	177.0 (3)
O3—Fe1—N1—C4	93.4 (3)	Fe1—N1—C2—C1	−3.7 (3)
N1i—Fe1—N1—C4	131 (100)	O2—C1—C2—N1	−177.5 (3)
O1i—Fe1—N1—C2	−176.5 (2)	O1—C1—C2—N1	1.4 (4)
O1—Fe1—N1—C2	3.5 (2)	O2—C1—C2—C3	−0.9 (5)
O3i—Fe1—N1—C2	94.2 (2)	O1—C1—C2—C3	178.0 (3)
O3—Fe1—N1—C2	−85.8 (2)	C5—N2—C3—C2	1.1 (6)
N1i—Fe1—N1—C2	−48 (100)	N1—C2—C3—N2	−0.5 (6)
O1i—Fe1—O1—C1	29 (100)	C1—C2—C3—N2	−177.0 (3)
O3i—Fe1—O1—C1	−90.8 (2)	C2—N1—C4—C5	−0.6 (5)
O3—Fe1—O1—C1	89.2 (2)	Fe1—N1—C4—C5	−179.8 (2)
N1i—Fe1—O1—C1	177.1 (2)	C3—N2—C5—C4	−1.5 (5)
N1—Fe1—O1—C1	−2.9 (2)	C3—N2—C5—C6	177.9 (3)
Fe1—O1—C1—O2	−179.3 (3)	N1—C4—C5—N2	1.3 (5)
Fe1—O1—C1—C2	1.9 (4)	N1—C4—C5—C6	−178.0 (3)

Symmetry codes: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O1ii	0.85	1.93	2.720 (3)	155
O3—H3B···O2iii	0.85	1.86	2.673 (3)	159

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