Poly[[di­aqua­hexa-μ-cyanido-cerium(III)ferrate(III)] dihydrate]

In the structure of the title complex, {[CeFe(CN)₆(H₂O)₂]·2H₂O}_n, the Ce^III and Fe^III atoms exhibit square anti­prismatic [CeN₆(H₂O)₂] (site symmetry m2m) and octahedral [FeC₆] (site symmetry 2/m) coordination geometries, respectively. The metal atoms are linked alternately through the cyanide groups, forming a three-dimensional framework in which the {Ce₂Fe₂(CN)₄} puckered square unit is the basic building block. The crystal packing is enforced by O—H⋯O and O—H⋯N hydrogen bonds, including the uncoordinated water molecule which is located on a mirror plane.

Related literature

For general background to hexa­cyanido­metalate(III)-based lanthanide complexes, see: Andruh et al. (2009). For related structures, see: Gramlich et al. (1990); Petter et al. (1989).

Experimental

Crystal data

• [CeFe(CN)₆(H₂O)₂]·2H₂O

• M_r = 424.15

• Orthorhombic, C m c m

• a = 7.3806 (11) Å

• b = 12.7836 (19) Å

• c = 13.619 (2) Å

• V = 1285.0 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 4.64 mm⁻¹

• T = 173 K

• 0.22 × 0.20 × 0.17 mm

Data collection

• Bruker APEXII diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2004) T_min = 0.428, T_max = 0.506

• 5578 measured reflections

• 831 independent reflections

• 785 reflections with I > 2σ(I)

• R_int = 0.088

Refinement

• R[F² > 2σ(F²)] = 0.037

• wR(F²) = 0.098

• S = 1.06

• 831 reflections

• 51 parameters

• H-atom parameters constrained

• Δρ_max = 1.08 e Å⁻³

• Δρ_min = −2.69 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯O2	0.85	2.08	2.807 (8)	144
O2—H2B⋯N1^i	0.85	2.28	3.126 (11)	177
Symmetry code: (i) .

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

S1. Comment

In the past few years, hexacyanometalate-based lanthanide assemblies have received much attention due to their intriguing topologies and interesting functionalities (Andruh et al., 2009). The chelated ligands have played an important role in the construction of low-dimensional complexes. Along this line, we have employed the K₃Fe(CN)₆ presusor to react with the Ce³⁺ ion in the presence of the bidentate chelated ligand 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen). Unexpectly, a new complex Ce(H₂O)₂Fe(CN)₆.2H₂O was obtained, in which the tmphen ligand was not involved. The structure of the title complex is similiar to those of LnFe(CN)₆.4H₂O (Ln = Sm—Lu) reported previously (Gramlich et al., 1990; Petter et al., 1989.).

Single crystal X-ray diffraction analysis revealed that the asymmetric unit of the title complex (Fig. 1) consists of one fourth of a [Ce(H₂O)₂]³⁺ cation, one fourth of a [Fe(CN)₆]^3- anion and one half of a water molecules of crystallization. Each iron(III) atom is six-coordinated by six bridging CN groups in a distorted octahedral geometry. The average Fe—C and C—N bond distances are 1.928 (5) and 1.166 (7) Å, respectively. The Fe—CN angles deviate slightly from the linearity, ranging from 178.3 (6) to 178.7 (8)°. Each cerium(III) atom is eight-coordinated with six cyano nitrogen atoms and two oxygen atoms from two coordinated water molecules, forming a square antiprismatic geometry. The Ce—O and the mean Ce—N bond distances are 2.351 (7) and 2.458 (5) Å, respectively. Due to the large ionic radii of the lanthanide atom, the cyanide bridges are exceptionally long and the Ce–N–C bonds are strongly bent with a mean angle of 160.0 (5)°, in opposition to the linearity of the Fe–C—N angle. As a consequence, adjacent Ce and Fe metals are connected through cyano groups to generate a three-dimensional open framework (Fig. 2). The 12-membered puckered square unit Ce₂Fe₂(CN)₄ is the basic building block, in which the Ce and Fe atoms occupy the corners and the CN linkages the edges. The crystal structure is stabilized by O—H···O and O—H···N hydrogen bonds (Table 1).

Related literature

For general background to hexacyanometalate(III)-based lanthanide complexes, see: Andruh et al. (2009). For related structures, see: Gramlich et al. (1990); Petter et al. (1989).

S2. Experimental

Single crystals of the title complex were prepared at room temperature by slow diffusion of an ethanol solution (3 ml) of Ce(NO₃)₃.6H₂O (0.10 mmol) and tmphen (0.20 mmol) into an aqueous solution (15 ml) of K₃[Fe(CN)₆].H₂O (0.10 mmol). After about one month, red block crystals were obtained.

S3. Refinement

All non-hydrogen atoms were refined with anisotropic thermal parameters. The water H atoms were located from a difference Fourier map and refined as riding with O—H = 0.85 Å and U(H) set to 1.5U_eq(O).

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

Fig. 1. ORTEP diagram of the title complex, showing 30% probability displacement ellipsoidw. Hydrogen atoms have been omitted for clarity. Symmetry codes: (i) -x + 5/2, -y + 1/2, z + 1/2; (ii) -x + 2, y, z; (iii) -x + 2, y, -z + 1/2; (iv) x, y, -z + 1/2; (v) -x + 2, -y, -z; (vi) x - 1/2, -y + 1/2, z - 1/2; (vii) -x + 5/2, y - 1/2, -z + 1/2; (viii) x - 1/2, y - 1/2, -z + 1/2; (ix) -x + 5/2, -y + 1/2, z - 1/2.

Fig. 2. The three-dimensional open framework of the title complex. Hydrogen atoms and uncoordinated water molecules are omitted for clarity.

Poly[[diaquahexa-µ-cyanido-cerium(III)ferrate(III)] dihydrate]

Crystal data

[CeFe(CN)6(H2O)2]·2H2O	F(000) = 808
Mr = 424.15	Dx = 2.193 Mg m^−3
Orthorhombic, Cmcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2c 2	Cell parameters from 3234 reflections
a = 7.3806 (11) Å	θ = 3.0–27.4°
b = 12.7836 (19) Å	µ = 4.64 mm^−1
c = 13.619 (2) Å	T = 173 K
V = 1285.0 (3) Å^3	Block, red
Z = 4	0.22 × 0.20 × 0.17 mm

Data collection

Bruker APEXII diffractometer	831 independent reflections
Radiation source: fine-focus sealed tube	785 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.088
phi and ω scans	θmax = 27.4°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −9→9
Tmin = 0.428, Tmax = 0.506	k = −16→16
5578 measured reflections	l = −17→17

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.098	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0233P)^2 + 48.4374P] where P = (Fo^2 + 2Fc^2)/3
831 reflections	(Δ/σ)max < 0.001
51 parameters	Δρmax = 1.08 e Å^−3
0 restraints	Δρmin = −2.69 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
C1	1.0000	0.1368 (7)	0.0590 (7)	0.0204 (18)
C2	1.3141 (9)	0.4530 (5)	0.4106 (5)	0.0208 (13)
Ce1	1.0000	0.32343 (4)	0.2500	0.0064 (2)
Fe1	1.0000	0.0000	0.0000	0.0164 (4)
N1	1.0000	0.2186 (6)	0.0965 (6)	0.0254 (17)
N2	1.2003 (9)	0.4229 (4)	0.3582 (5)	0.0285 (13)
O1	0.7401 (11)	0.2171 (6)	0.2500	0.0347 (17)
H1A	0.7129	0.1879	0.3042	0.052*
O2	0.5000	0.1562 (6)	0.3993 (6)	0.0342 (17)
H2A	0.5000	0.0914	0.4131	0.051*
H2B	0.5000	0.1922	0.4518	0.051*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.022 (5)	0.022 (4)	0.017 (4)	0.000	0.000	−0.001 (4)
C2	0.021 (3)	0.021 (3)	0.021 (3)	−0.002 (2)	0.000 (3)	−0.003 (2)
Ce1	0.0053 (3)	0.0080 (3)	0.0058 (3)	0.000	0.000	0.000
Fe1	0.0150 (8)	0.0176 (8)	0.0164 (9)	0.000	0.000	0.0002 (6)
N1	0.025 (4)	0.026 (4)	0.025 (4)	0.000	0.000	−0.002 (3)
N2	0.026 (3)	0.033 (3)	0.026 (3)	−0.005 (2)	−0.001 (3)	−0.002 (2)
O1	0.029 (4)	0.049 (4)	0.026 (4)	−0.015 (4)	0.000	0.000
O2	0.035 (4)	0.036 (4)	0.032 (4)	0.000	0.000	0.002 (3)

Geometric parameters (Å, º)

C1—N1	1.163 (12)	Ce1—N1	2.483 (8)
C1—Fe1	1.925 (9)	Ce1—N1^iv	2.483 (8)
C2—N2	1.167 (9)	Fe1—C1^v	1.925 (9)
C2—Fe1^i	1.930 (7)	Fe1—C2^vi	1.930 (7)
Ce1—O1	2.351 (7)	Fe1—C2^vii	1.930 (7)
Ce1—O1^ii	2.351 (7)	Fe1—C2^viii	1.930 (7)
Ce1—N2	2.444 (6)	Fe1—C2^ix	1.930 (7)
Ce1—N2^iii	2.444 (6)	O1—H1A	0.8503
Ce1—N2^ii	2.444 (6)	O2—H2A	0.8500
Ce1—N2^iv	2.444 (6)	O2—H2B	0.8500
N1—C1—Fe1	178.7 (8)	N2—Ce1—N1^iv	76.9 (2)
N2—C2—Fe1^i	178.3 (6)	N2^iii—Ce1—N1^iv	142.05 (16)
O1—Ce1—O1^ii	109.4 (4)	N2^ii—Ce1—N1^iv	76.9 (2)
O1—Ce1—N2	142.58 (15)	N2^iv—Ce1—N1^iv	142.05 (16)
O1^ii—Ce1—N2	78.9 (2)	N1—Ce1—N1^iv	114.7 (4)
O1—Ce1—N2^iii	78.9 (2)	C1^v—Fe1—C1	180.0 (5)
O1^ii—Ce1—N2^iii	142.58 (15)	C1^v—Fe1—C2^vi	91.1 (3)
N2—Ce1—N2^iii	117.3 (3)	C1—Fe1—C2^vi	88.9 (3)
O1—Ce1—N2^ii	78.9 (2)	C1^v—Fe1—C2^vii	88.9 (3)
O1^ii—Ce1—N2^ii	142.58 (15)	C1—Fe1—C2^vii	91.1 (3)
N2—Ce1—N2^ii	74.4 (3)	C2^vi—Fe1—C2^vii	180.0 (4)
N2^iii—Ce1—N2^ii	74.2 (3)	C1^v—Fe1—C2^viii	88.9 (3)
O1—Ce1—N2^iv	142.58 (15)	C1—Fe1—C2^viii	91.1 (3)
O1^ii—Ce1—N2^iv	78.9 (2)	C2^vi—Fe1—C2^viii	89.4 (4)
N2—Ce1—N2^iv	74.2 (3)	C2^vii—Fe1—C2^viii	90.6 (4)
N2^iii—Ce1—N2^iv	74.4 (3)	C1^v—Fe1—C2^ix	91.1 (3)
N2^ii—Ce1—N2^iv	117.3 (3)	C1—Fe1—C2^ix	88.9 (3)
O1—Ce1—N1	71.82 (14)	C2^vi—Fe1—C2^ix	90.6 (4)
O1^ii—Ce1—N1	71.82 (14)	C2^vii—Fe1—C2^ix	89.4 (4)
N2—Ce1—N1	142.05 (16)	C2^viii—Fe1—C2^ix	180.0 (4)
N2^iii—Ce1—N1	76.9 (2)	C1—N1—Ce1	148.7 (8)
N2^ii—Ce1—N1	142.05 (16)	C2—N2—Ce1	167.2 (5)
N2^iv—Ce1—N1	76.9 (2)	Ce1—O1—H1A	116.5
O1—Ce1—N1^iv	71.82 (14)	H2A—O2—H2B	110.0
O1^ii—Ce1—N1^iv	71.82 (14)

Symmetry codes: (i) −x+5/2, −y+1/2, z+1/2; (ii) −x+2, y, z; (iii) −x+2, y, −z+1/2; (iv) x, y, −z+1/2; (v) −x+2, −y, −z; (vi) x−1/2, −y+1/2, z−1/2; (vii) −x+5/2, y−1/2, −z+1/2; (viii) x−1/2, y−1/2, −z+1/2; (ix) −x+5/2, −y+1/2, z−1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O2	0.85	2.08	2.807 (8)	144
O2—H2B···N1^x	0.85	2.28	3.126 (11)	177

Symmetry code: (x) −x+3/2, −y+1/2, z+1/2.