Hexa­kis­(dimethyl­formamide-κO)manganese(II) μ-oxido-bis­[trichlorido­ferrate(III)]

Abstract

The title compound, [Mn(C₃H₇NO)₆][Fe₂Cl₆O], was obtained unintentionally as a product of an attempted synthesis of heterometallic complexes with Schiff base ligands using manganese powder and FeCl₃·6H₂O as starting materials. In the [Fe₂OCl₆]²⁻ anion, the O atom and the Fe atom occupy positions with site symmetry and 3, respectively, resulting in a linear Fe—O—Fe angle and a staggered conformation. The octa­hedrally surrounded cation (site symmetry ) and the [Fe₂Cl₆O]²⁻ anion are alternately stacked along [001].

Related literature

For structures including [Mn(dmf)₆]²⁺ cations, see: Khutornoi et al. (2002 ▶). For stuctures including [Fe(dmf)₆]²⁺, see: Albanati et al. (2007 ▶); Baumgartner (1986 ▶); Li et al. (2007a ▶,b ▶); Lode & Krautscheid (2000 ▶); Müller et al. (1989a ▶,b ▶); Qiutian et al. (1983 ▶); Silva et al. (2008 ▶); Young et al. (1989 ▶). For the isostructural complex [Mg(dmf)₆][Fe₂OCl₆], see: Juang et al. (1984 ▶). For bond-valence-sum calculations, see: Brown & Altermatt (1985 ▶). For related direct syntheses, see: Garnovskii et al. (1999 ▶).

Experimental

Crystal data

• [Mn(C₃H₇NO)₆][Fe₂Cl₆O]

• M _r = 833.92

• Trigonal,

• a = 14.0171 (8) Å

• c = 15.3966 (14) Å

• V = 2619.8 (3) ų

• Z = 3

• Mo Kα radiation

• μ = 1.68 mm⁻¹

• T = 173 K

• 0.60 × 0.40 × 0.40 mm

Data collection

• Oxford Diffraction Xcalibur/Sapphire3 diffractometer

• Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2010 ▶) T _min = 0.557, T _max = 1.000

• 16066 measured reflections

• 1624 independent reflections

• 1323 reflections with I > 2σ(I)

• R _int = 0.067

Refinement

• R[F ² > 2σ(F ²)] = 0.039

• wR(F ²) = 0.092

• S = 0.98

• 1624 reflections

• 68 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 1.05 e Å⁻³

• Δρ_min = −0.37 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2010 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: XP in SHELXTL; software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

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

Table 1. Selected bond lengths (Å).

Mn1—O1	2.1736 (15)
Fe1—O1S	1.7758 (5)
Fe1—Cl1	2.2330 (6)

supplementary crystallographic information

Comment

Continuing our research on direct synthesis of bimetallic complexes with Schiff base ligands, i.e. one-pot synthesis with the use of metal powders or their oxides as starting materials (Garnovskii et al., 1999), we present here a new Mn^II/Fe^III complex, which was obtained as a by-product during the investigation of the system: Mn⁰ – FeCl₃.6H₂O – salicylic aldehyde – glycine – Et₃N – dmf (dimethylformamide).

The crystal structure of the title complex, (I), is shown in Fig. 1. Six dmf molecules coordinate to the Mn²⁺ ion forming the almost regular octahedral complex cation [Mn(dmf)₆]²⁺ [site symmetry 3; Mn1—O1 distances of 2.1736 (15) Å and O1–Mn1–O1 bond angles of 87.49 (6), 92.51 (6) and 180°]. Since the neighbouring elements Mn and Fe are difficult to distinguish by X-ray methods, a comparison of Mn^II—O and Fe^II—O bond lengths can be useful in the assignment of the correct metal to this polyhedron. The observed metal–O_dmf distances are in good agreement with those in [Mn(dmf)₆][Mo₆Br₈(NCS)₆] [2.152Å (Khutornoi et al., 2002)]. An additional argument for Mn in the cation as the correct metal, but not its Fe analogue, is the analysis of crystallographic data for 10 structures containing [Fe(dmf)₆]²⁺ (Albanati et al., 2007; Baumgartner, 1986; Li et al., 2007a,b; Lode & Krautscheid, 2000; Müller et al., 1989a,b; Qiutian et al., 1983; Silva et al., 2008; Young et al., 1989) where Fe—O bond lengths in the range of 1.99 – 2.16 Å with an average value of 2.11 Å are found. Moreover, no Fe^II complexes with a regular octahedral dmf environment have been found.

The [Fe₂OCl₆]^2- anion possesses D_3d geometry with Fe and O atoms in special positions (3 and 3, respectively) that force the Fe—O—Fe angle to be linear and the anion to adopt a staggered conformation (Fig. 2). The Fe³⁺ atom has a distorted tetrahedral coordination with an Fe1–O1S distances of 1.7758 (5) Å, an Fe1–Cl1 distance of 2.2330 (6) Å, and bond angles of 106.348 (19) and 112. 438 (17)° for Cl1–Fe1–Cl1 and Cl1–Fe1–O1S, respectively. The oxidation states (+II) and (+III) for hexa-coordinate Mn and four-coordinate Fe atoms are supported by bond-valence sum calculations [1.914 for Mn²⁺ and 3.099 for Fe³⁺ (Brown & Altermatt, 1985)].

The [Mn(dmf)₆]²⁺ cations and [Fe₂OCl₆]^2- anions are arranged in such a way that the cations and anions are arranged alternatingly along the [001] direction (Fig. 3).

The described complex (I) can be supposed as isostructural to [Mg(dmf)₆][Fe₂OCl₆] (Juang et al., 1984) but interestingly the volume of the unit cell in case of the manganese complex is ca 200 ų less than that of the magnesium complex.

Experimental

Salicylic aldehyde (0.31 g, 2.5 mmol), glycine (0.19 g, 2.5 mmol) and triethylamine (0.35 mmol, 2.5 mmol) were dissolved in dimethylformamide (dmf; 25 ml) in this order, and stirred at 323 – 333 K (10 min). Then, manganese powder (0.14 g, 2.5 mmol) and FeCl₃.6H₂O (0.68 g, 2.5 mmol) were added to the hot yellow solution with stirring for 3 h, until total dissolution of manganese was observed. The resulting solution was filtered and subsequently pale pink crystals suitable for X-ray crystallography were separated after eight days at successive addition of a PrⁱOH. Yield: 0.23 g, 21.5% (per iron). Elemental analysis for C₁₈H₄₂MnFe₂N₆O₇Cl₆ (Mr= 833.92). Calcd: C, 25.93; N, 10.08; H, 5.08; Fe, 13.39; Mn, 6.59. Found: C, 26.1; N, 10.0; H, 5.0; Fe, 13.3; Mn, 6.3. IR(KBr, cm^-1): 3344(br), 2924(m), 1629(m), 1572(w), 1557(w), 1535(w), 1521(w), 1470(w), 1412(br), 1312(w), 1580(w), 1174(w), 1154(w), 1041(w), 952(w), 851(w), 689(s), 482(w), 443(w). The compound is sparingly soluble in dimethylsulfoxide (dmso), dmf, and H₂O. In the IR spectrum of (I), the band corresponding to ν(CO) in dmf is shifted to the region of longer wavelenghts (1629 cm^-1) relative to this band in the spectrum of noncoordinating dmf (1675 cm^-1).

Refinement

The carbonyl H atom was found from a difference Fourier map and was refined freely. Methyl H atoms were allowed to ride on their attached atoms with C—H = 0.98 (1)Å and U_iso(H)= 1.5Ueq(C). The highest remaining difference Fourier peak is located 0.87 Å from atom O1S.

Figures

Fig. 1.

Parts of the structure of (I), with atom labels and 50% probability displacement ellipsoids. Hydrogen atoms were omitted for clarity.

Fig. 2.

The crystal packing of (I) showing a staggerded conformation of the [Fe2OCl6]2- anion. Colour code as in Fig. 1; hydrogen atoms were omitted for clarity.

Fig. 3.

The crystal packing of (I) showing the linear arrangement of Fe–O–Fe mojeties and Mn atoms. Colour code as in Fig. 1; hydrogen atoms were omitted for clarity.

Crystal data

[Mn(C3H7NO)6][Fe2Cl6O]	Dx = 1.586 Mg m−3
Mr = 833.92	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3	Cell parameters from 2653 reflections
Hall symbol: -R 3	θ = 2.9–32.5°
a = 14.0171 (8) Å	µ = 1.68 mm−1
c = 15.3966 (14) Å	T = 173 K
V = 2619.8 (3) Å3	Block, red
Z = 3	0.60 × 0.40 × 0.40 mm
F(000) = 1281

Data collection

Oxford Diffraction Xcalibur/Sapphire3 diffractometer	1624 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1323 reflections with I > 2σ(I)
graphite	Rint = 0.067
Detector resolution: 16.1827 pixels mm-1	θmax = 30.0°, θmin = 2.9°
ω scans	h = −19→19
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2010)	k = −19→15
Tmin = 0.557, Tmax = 1.000	l = −20→18
16066 measured reflections

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)] = 0.039	Hydrogen site location: difference Fourier map
wR(F2) = 0.092	H atoms treated by a mixture of independent and constrained refinement
S = 0.98	w = 1/[σ2(Fo2) + (0.0428P)2] where P = (Fo2 + 2Fc2)/3
1624 reflections	(Δ/σ)max < 0.001
68 parameters	Δρmax = 1.05 e Å−3
0 restraints	Δρmin = −0.37 e Å−3
0 constraints

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
Mn1	0.0000	0.0000	0.5000	0.02020 (19)
N1	0.23962 (14)	−0.02345 (15)	0.65588 (11)	0.0223 (4)
Fe1	0.0000	0.0000	0.88467 (3)	0.02113 (16)
O1	0.08798 (13)	−0.06054 (12)	0.57785 (10)	0.0262 (4)
Cl1	0.03397 (5)	−0.12729 (4)	0.82931 (3)	0.02609 (16)
C1	0.15838 (18)	−0.00668 (18)	0.63362 (15)	0.0232 (4)
H1	0.1622 (18)	0.0567 (19)	0.6623 (13)	0.015 (6)*
O1S	0.0000	0.0000	1.0000	0.0282 (8)
C2	0.2521 (2)	−0.1115 (2)	0.61800 (16)	0.0318 (5)
H2A	0.1939	−0.1512	0.5750	0.048*
H2B	0.2467	−0.1626	0.6638	0.048*
H2C	0.3242	−0.0802	0.5897	0.048*
C3	0.3184 (2)	0.0425 (2)	0.72297 (17)	0.0347 (6)
H3A	0.3143	−0.0055	0.7709	0.052*
H3B	0.3010	0.0977	0.7446	0.052*
H3C	0.3929	0.0795	0.6985	0.052*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Mn1	0.0176 (2)	0.0176 (2)	0.0254 (4)	0.00880 (12)	0.000	0.000
N1	0.0200 (9)	0.0211 (9)	0.0259 (9)	0.0104 (7)	−0.0009 (7)	0.0000 (7)
Fe1	0.02076 (19)	0.02076 (19)	0.0219 (3)	0.01038 (10)	0.000	0.000
O1	0.0238 (8)	0.0209 (8)	0.0340 (9)	0.0112 (7)	−0.0040 (6)	0.0015 (6)
Cl1	0.0271 (3)	0.0233 (3)	0.0303 (3)	0.0145 (2)	0.0021 (2)	0.00083 (19)
C1	0.0209 (11)	0.0185 (10)	0.0296 (11)	0.0093 (9)	0.0026 (8)	0.0041 (8)
O1S	0.0274 (13)	0.0274 (13)	0.030 (2)	0.0137 (6)	0.000	0.000
C2	0.0373 (14)	0.0370 (13)	0.0331 (13)	0.0278 (12)	−0.0034 (10)	−0.0044 (10)
C3	0.0339 (13)	0.0269 (13)	0.0446 (14)	0.0162 (11)	−0.0151 (11)	−0.0065 (10)

Geometric parameters (Å, °)

Mn1—O1i	2.1736 (15)	Fe1—Cl1	2.2330 (6)
Mn1—O1ii	2.1736 (15)	Fe1—Cl1v	2.2330 (6)
Mn1—O1	2.1736 (15)	O1—C1	1.239 (3)
Mn1—O1iii	2.1736 (15)	C1—H1	0.97 (2)
Mn1—O1iv	2.1736 (15)	O1S—Fe1vi	1.7758 (5)
Mn1—O1v	2.1736 (15)	C2—H2A	0.9800
N1—C1	1.318 (3)	C2—H2B	0.9800
N1—C2	1.453 (3)	C2—H2C	0.9800
N1—C3	1.456 (3)	C3—H3A	0.9800
Fe1—O1S	1.7758 (5)	C3—H3B	0.9800
Fe1—Cl1ii	2.2330 (6)	C3—H3C	0.9800
O1i—Mn1—O1ii	180.00 (6)	O1S—Fe1—Cl1v	112.438 (17)
O1i—Mn1—O1	87.49 (6)	Cl1ii—Fe1—Cl1v	106.348 (19)
O1ii—Mn1—O1	92.51 (6)	Cl1—Fe1—Cl1v	106.348 (19)
O1i—Mn1—O1iii	92.51 (6)	C1—O1—Mn1	125.35 (15)
O1ii—Mn1—O1iii	87.49 (6)	O1—C1—N1	124.6 (2)
O1—Mn1—O1iii	180.00 (7)	O1—C1—H1	122.4 (13)
O1i—Mn1—O1iv	92.51 (6)	N1—C1—H1	112.8 (13)
O1ii—Mn1—O1iv	87.49 (6)	Fe1vi—O1S—Fe1	180.0
O1—Mn1—O1iv	87.49 (6)	N1—C2—H2A	109.5
O1iii—Mn1—O1iv	92.51 (6)	N1—C2—H2B	109.5
O1i—Mn1—O1v	87.49 (6)	H2A—C2—H2B	109.5
O1ii—Mn1—O1v	92.51 (6)	N1—C2—H2C	109.5
O1—Mn1—O1v	92.51 (6)	H2A—C2—H2C	109.5
O1iii—Mn1—O1v	87.49 (6)	H2B—C2—H2C	109.5
O1iv—Mn1—O1v	180.00 (7)	N1—C3—H3A	109.5
C1—N1—C2	121.94 (18)	N1—C3—H3B	109.5
C1—N1—C3	121.34 (19)	H3A—C3—H3B	109.5
C2—N1—C3	116.65 (18)	N1—C3—H3C	109.5
O1S—Fe1—Cl1ii	112.438 (17)	H3A—C3—H3C	109.5
O1S—Fe1—Cl1	112.438 (17)	H3B—C3—H3C	109.5
Cl1ii—Fe1—Cl1	106.348 (19)
O1i—Mn1—O1—C1	169.64 (18)	Mn1—O1—C1—N1	−152.23 (16)
O1ii—Mn1—O1—C1	−10.36 (18)	C2—N1—C1—O1	−2.2 (3)
O1iv—Mn1—O1—C1	77.01 (14)	C3—N1—C1—O1	−179.2 (2)
O1v—Mn1—O1—C1	−102.99 (14)

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