Crystal structure of the coordination polymer [Fe^III₂{Pt^II(CN)₄}₃]

The title complex, poly[dodeca-μ-cyanido-diiron(III)triplat­inum(II)], [Fe^III₂{Pt^II(CN)₄}₃], has a three-dimensional polymeric structure. It is built-up from square-planar [Pt^II(CN)₄]²⁻ anions (point group symmetry 2/m) bridging cationic [Fe^IIIPt^II(CN)₄]⁺_∞ layers extending in the bc plane. The Fe^II atoms of the layers are located on inversion centres and exhibit an octa­hedral coordination sphere defined by six N atoms of cyanide ligands, while the Pt^II atoms are located on twofold rotation axes and are surrounded by four C atoms of the cyanide ligands in a square-planar coordination. The geometrical preferences of the two cations for octa­hedral and square-planar coordination, respectively, lead to a corrugated organisation of the layers. The distance between neighbouring [Fe^IIIPt^II(CN)₄]⁺_∞ layers corresponds to the length a/2 = 8.0070 (3) Å, and the separation between two neighbouring Pt^II atoms of the bridging [Pt^II(CN)₄]²⁻ groups corresponds to the length of the c axis [7.5720 (2) Å]. The structure is porous with accessible voids of 390 ų per unit cell.

1. Related literature

Coordination compounds have inter­esting properties in catal­ysis (Kanderal et al., 2005; Penkova et al., 2009) or as photoactive materials (Yan et al., 2012). Magnetically active polycyanidometallate network complexes of Fe^II [Fe^IIL₂{M^I(CN)₂}₂] or [Fe^IIL₂{M^II(CN)₄}] (M^I = Ag, Au; M^II = Ni, Pd, Pt; L = N-heterocyclic ligand) have been studied because they show versatile polymeric structures (Piñeiro-López et al. 2014; Seredyuk et al., 2007, 2009), spin transition (Muñoz & Real, 2013) and functionalities such as sorption–desorption of organic and inorganic mol­ecules (Muñoz & Real, 2013) or reversible chemosorption (Arcís-Castillo et al., 2013).

2. Experimental

2.1. Crystal data

• [Fe₂Pt₃(CN)₁₂]

• M_r = 1009.18

• Monoclinic, C 2/m

• a = 16.0140 (5) Å

• b = 13.8250 (5) Å

• c = 7.5720 (2) Å

• β = 102.946 (2)°

• V = 1633.78 (9) ų

• Z = 2

• Mo Kα radiation

• μ = 13.68 mm⁻¹

• T = 293 K

• 0.04 × 0.04 × 0.02 mm

2.2. Data collection

• Oxford Diffraction Gemini S Ultra diffractometer

• Absorption correction: multi-scan (Blessing, 1995) T_min = 0.611, T_max = 0.772

• 3358 measured reflections

• 1909 independent reflections

• 1568 reflections with I > 2σ(I)

• R_int = 0.038

2.3. Refinement

• R[F² > 2σ(F²)] = 0.038

• wR(F²) = 0.106

• S = 0.97

• 1909 reflections

• 71 parameters

• Δρ_max = 1.25 e Å⁻³

• Δρ_min = −1.33 e Å⁻³

Data collection: COLLECT (Nonius, 1999); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 2012).

Supporting information

S1. Synthesis and crystallization

Single crystals of the title compound were grown using a slow diffusion technique. During the reaction time a side product had formed serendipitously due to oxidation of the initial Fe^II salt. One side of a multi-arm shaped vessel contained (NH₄)₂Fe(SO₄)₂·6H₂O (20 mg, 51 mmol) dissolved in water (0.5 mL). The second arm contained K₂[Pt(CN)₄]·3H₂O (22 mg, 51 mmol) in water (0.5 ml). The vessel was filled with a water/methanol (1:1) solution. Square shaped orange crystals suitable for single crystal X-ray analysis were obtained after several weeks.

S2. Refinement

The highest and lowest remaining electron density are located 3.66 and 0.83 Å, respectively, from the Pt atom. The highest electron densities are connected with positions in the voids of the framework. However, modelling of the electron density e.g. under consideration of disordered (partially occupied) water molecules lead to implausible models.

Related literature

Coordination compounds have interesting properties in catalysis (Kanderal et al., 2005; Penkova et al., 2009) or as photoactive materials (Yan et al., 2012). Magnetically active polycyanidometallate network complexes of Fe^II [Fe^IIL₂{M^I(CN)₂}₂] or [Fe^IIL₂{M^II(CN)₄}] (M^I = Ag, Au; M^II = Ni, Pd, Pt; L = N-heterocyclic ligand) have been studied because they show versatile polymeric structures (Piñeiro-López et al. 2014; Seredyuk et al., 2007, 2009), spin transition (Muñoz & Real, 2013) and functionalities such as sorption–desorption of organic and inorganic molecules (Muñoz & Real, 2013) or reversible chemosorption (Arcís-Castillo et al., 2013).

Structure description

Coordination compounds have interesting properties in catalysis (Kanderal et al., 2005; Penkova et al., 2009) or as photoactive materials (Yan et al., 2012). Magnetically active polycyanidometallate network complexes of Fe^II [Fe^IIL₂{M^I(CN)₂}₂] or [Fe^IIL₂{M^II(CN)₄}] (M^I = Ag, Au; M^II = Ni, Pd, Pt; L = N-heterocyclic ligand) have been studied because they show versatile polymeric structures (Piñeiro-López et al. 2014; Seredyuk et al., 2007, 2009), spin transition (Muñoz & Real, 2013) and functionalities such as sorption–desorption of organic and inorganic molecules (Muñoz & Real, 2013) or reversible chemosorption (Arcís-Castillo et al., 2013).

Synthesis and crystallization

Single crystals of the title compound were grown using a slow diffusion technique. During the reaction time a side product had formed serendipitously due to oxidation of the initial Fe^II salt. One side of a multi-arm shaped vessel contained (NH₄)₂Fe(SO₄)₂·6H₂O (20 mg, 51 mmol) dissolved in water (0.5 mL). The second arm contained K₂[Pt(CN)₄]·3H₂O (22 mg, 51 mmol) in water (0.5 ml). The vessel was filled with a water/methanol (1:1) solution. Square shaped orange crystals suitable for single crystal X-ray analysis were obtained after several weeks.

Refinement details

The highest and lowest remaining electron density are located 3.66 and 0.83 Å, respectively, from the Pt atom. The highest electron densities are connected with positions in the voids of the framework. However, modelling of the electron density e.g. under consideration of disordered (partially occupied) water molecules lead to implausible models.

Computing details

Data collection: COLLECT (Nonius, 1999); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures

	Fig. 1. Displacement ellipsoid plot (30% probability level) of the principal building units of the structure of the title compound. [Symmetry codes: (i) 1/2 + x, 1/2 + y, 1 + z; (ii) 0.5 – x, 1/2 + y, 1 – z, (iii) x, 1 – y, 1 + z.]
	Fig. 2. A fragment of three-dimentional coordination polymer of the title compound in a perspective view along c. Polyhedra correspond to FeN6 and PtC4 chromophores.

Poly[dodeca-µ-cyanido-diiron(III)triplatinum(II)]

Crystal data

[Fe2Pt3(CN)12]	F(000) = 884
Mr = 1009.18	Dx = 2.051 Mg m^−3
Monoclinic, C2/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2y	Cell parameters from 200 reflections
a = 16.0140 (5) Å	θ = 12–20°
b = 13.8250 (5) Å	µ = 13.68 mm^−1
c = 7.5720 (2) Å	T = 293 K
β = 102.946 (2)°	Prismatic, orange
V = 1633.78 (9) Å^3	0.04 × 0.04 × 0.02 mm
Z = 2

Data collection

Oxford Diffraction Gemini S Ultra diffractometer	1909 independent reflections
Radiation source: fine-focus sealed tube	1568 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
ω scans	θmax = 27.5°, θmin = 3.0°
Absorption correction: multi-scan (Blessing, 1995)	h = −20→20
Tmin = 0.611, Tmax = 0.772	k = −17→16
3358 measured reflections	l = −9→9

Refinement

Refinement on F^2	0 constraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.038	Secondary atom site location: difference Fourier map
wR(F^2) = 0.106	w = 1/[σ^2(Fo^2) + (0.0615P)^2 + 15.455P] where P = (Fo^2 + 2Fc^2)/3
S = 0.97	(Δ/σ)max < 0.001
1909 reflections	Δρmax = 1.25 e Å^−3
71 parameters	Δρmin = −1.33 e Å^−3
0 restraints

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
Pt1	0.0000	0.0000	0.0000	0.02376 (17)
Pt2	0.19452 (3)	0.5000	0.47749 (5)	0.02524 (16)
Fe	0.2500	0.2500	0.0000	0.0215 (3)
N1	0.1335 (5)	0.1622 (5)	−0.0284 (10)	0.0368 (17)
N2	0.2081 (6)	0.3449 (5)	0.1843 (10)	0.0400 (18)
N3	0.3039 (6)	0.1577 (5)	0.2273 (10)	0.0385 (17)
C1	0.0859 (5)	0.1023 (6)	−0.0190 (12)	0.0310 (17)
C2	0.2001 (6)	0.4002 (6)	0.2915 (11)	0.0335 (19)
C3	0.3072 (6)	0.1012 (6)	0.3373 (10)	0.0312 (18)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pt1	0.0208 (3)	0.0167 (3)	0.0343 (3)	0.000	0.0073 (2)	0.000
Pt2	0.0389 (3)	0.0182 (2)	0.0195 (2)	0.000	0.00824 (18)	0.000
Fe	0.0294 (8)	0.0165 (7)	0.0199 (7)	−0.0040 (6)	0.0083 (6)	−0.0004 (5)
N1	0.041 (4)	0.026 (4)	0.042 (4)	−0.009 (3)	0.008 (4)	−0.002 (3)
N2	0.056 (5)	0.030 (4)	0.038 (4)	−0.004 (4)	0.017 (4)	−0.006 (3)
N3	0.053 (5)	0.026 (4)	0.037 (4)	0.002 (4)	0.011 (4)	0.006 (3)
C1	0.028 (4)	0.023 (4)	0.043 (4)	0.000 (3)	0.011 (4)	0.004 (3)
C2	0.050 (6)	0.026 (4)	0.026 (4)	0.003 (4)	0.012 (4)	−0.001 (3)
C3	0.045 (5)	0.021 (4)	0.025 (4)	−0.001 (4)	0.004 (4)	0.000 (3)

Geometric parameters (Å, º)

Pt1—C1	2.000 (8)	Fe—N2	2.130 (7)
Pt1—C1^i	2.000 (8)	Fe—N3^vii	2.161 (7)
Pt1—C1^ii	2.000 (8)	Fe—N3	2.161 (7)
Pt1—C1^iii	2.000 (8)	Fe—N1^vii	2.195 (7)
Pt2—C3^iv	1.986 (8)	Fe—N1	2.195 (7)
Pt2—C3^v	1.986 (8)	N1—C1	1.139 (10)
Pt2—C2	1.988 (8)	N2—C2	1.143 (11)
Pt2—C2^vi	1.988 (8)	N3—C3	1.134 (10)
Fe—N2^vii	2.130 (7)	C3—Pt2^v	1.986 (8)
C1—Pt1—C1^i	90.0 (5)	N3^vii—Fe—N3	180.0 (3)
C1—Pt1—C1^ii	180.0 (6)	N2^vii—Fe—N1^vii	91.1 (3)
C1^i—Pt1—C1^ii	90.0 (5)	N2—Fe—N1^vii	88.9 (3)
C1—Pt1—C1^iii	90.0 (5)	N3^vii—Fe—N1^vii	86.0 (3)
C1^i—Pt1—C1^iii	180.0 (6)	N3—Fe—N1^vii	94.0 (3)
C1^ii—Pt1—C1^iii	90.0 (5)	N2^vii—Fe—N1	88.9 (3)
C3^iv—Pt2—C3^v	89.6 (4)	N2—Fe—N1	91.1 (3)
C3^iv—Pt2—C2	178.1 (4)	N3^vii—Fe—N1	94.0 (3)
C3^v—Pt2—C2	91.2 (3)	N3—Fe—N1	86.0 (3)
C3^iv—Pt2—C2^vi	91.2 (3)	N1^vii—Fe—N1	180.0 (2)
C3^v—Pt2—C2^vi	178.1 (4)	C1—N1—Fe	164.2 (7)
C2—Pt2—C2^vi	87.9 (5)	C2—N2—Fe	168.3 (8)
N2^vii—Fe—N2	180.0 (5)	C3—N3—Fe	159.4 (8)
N2^vii—Fe—N3^vii	88.3 (3)	N1—C1—Pt1	178.3 (7)
N2—Fe—N3^vii	91.7 (3)	N2—C2—Pt2	175.9 (9)
N2^vii—Fe—N3	91.7 (3)	N3—C3—Pt2^v	176.4 (8)
N2—Fe—N3	88.3 (3)

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