(2,2′-Biquinoline-κ2 N,N′)dichlorido­iron(II)

Narjes Rahimi; Nasser Safari; Vahid Amani; Hamid Reza Khavasi

doi:10.1107/S1600536809041439

. 2009 Oct 17;65(Pt 11):m1370. doi: 10.1107/S1600536809041439

(2,2′-Biquinoline-κ² N,N′)dichloridoiron(II)

Narjes Rahimi ^a, Nasser Safari ^a,^*, Vahid Amani ^a, Hamid Reza Khavasi ^a

PMCID: PMC2971346 PMID: 21578122

Abstract

In the title compound, [FeCl₂(C₁₈H₁₂N₂)], the Fe^II atom is four-coordinated in a distorted tetrahedral arrangement by an N,N′-bidentate 2,2′-biquinoline ligand and two chloride ions. In the crystal, there are extensive π–π contacts between the pyridine rings [centroid–centroid distances = 3.7611 (3), 3.7603 (4), 3.5292 (4), 3.5336 (5) and 3.6656 (4) Å].

Related literature

For related structures, see: Amani et al. (2009 ▶); Amani, Safari & Khavasi (2007 ▶); Amani, Safari, Khavasi & Mirzaei (2007 ▶); Chan & Baird (2004 ▶); Gibson et al. (2002 ▶); Handley et al. (2001 ▶); Khavasi et al. (2007 ▶, 2008 ▶). For bond-length data, see: Figgis et al. (1983 ▶); Kulkarni et al. (1998 ▶).

Experimental

Crystal data

[FeCl₂(C₁₈H₁₂N₂)]
M _r = 383.05
Monoclinic,
a = 7.9777 (6) Å
b = 12.2268 (11) Å
c = 16.9904 (12) Å
β = 102.899 (6)°
V = 1615.5 (2) Å³
Z = 4
Mo Kα radiation
μ = 1.26 mm⁻¹
T = 298 K
0.45 × 0.43 × 0.31 mm

Data collection

Stoe IPDS II diffractometer
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 2005 ▶) T _min = 0.577, T _max = 0.681
13058 measured reflections
4323 independent reflections
3739 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.093
S = 1.06
4323 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.52 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2005 ▶); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2005 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809041439/hb5133sup1.cif

e-65-m1370-sup1.cif^{(19.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809041439/hb5133Isup2.hkl

e-65-m1370-Isup2.hkl^{(207.6KB, hkl)}

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

Table 1. Selected geometric parameters (Å, °).

Fe1—N1	2.1051 (14)
Fe1—N2	2.1008 (15)
Fe1—Cl2	2.2265 (6)
Fe1—Cl1	2.2341 (7)

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N2—Fe1—N1

78.06 (6)

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Acknowledgments

We are grateful to the Shahid Beheshti University for financial support.

supplementary crystallographic information

Comment

Recently, we reported the synthes and crystal structure of iron (III) hetero-ligand complexes such as [Fe(bipy)Cl₄][bipy.H], (II), [Fe(5,5'-dmbpy)₂Cl₂][FeCl₄], (III), (Amani, Safari & Khavasi 2007), [Fe(phen)Cl₃(CH₃OH)].CH₃OH, (IV), (Khavasi et al., 2007), [Fe(bipy)Cl₃(DMSO)], (V) and [Fe(phen)Cl₃(DMSO)], (VI), (Amani, Safari, khavasi & Mirzaei, 2007), [Fe(phen)Cl₄][phen.H], (VII), (Khavasi et al., 2008), [Fe(4,4'-dmbpy)Cl₄][4,4'-dmbpy.H], (VIII) and [Fe(4,4'-dmbpy)Cl₃(DMSO)], (IX), (Amani et al., 2009) [where bipy is 2,2'-bipyridine, 5,5'-dmbpy is 5,5'-dimethyl-2,2'-bipyridine, phen is 1,10-phenanthroline, DMSO is dimethyl sulfoxide and 4,4'-dmbpy is 4,4'-dimethyl-2,2'-bipyridine].

There are several Fe^II complexes, with formula, [FeCl₂(N—N)], such as [FeCl₂(6,6'-dmbpy)], (X), (Chan & Baird 2004), [FeCl₂(BDP)], (XI), (Handley et al., 2001) and [FeCl₂(DEI)], (XII), (Gibson et al., 2002) [where 6,6'-dmbpy is 6, 6'-dimethyl-2, 2'-bipyridine, BDP is 1,3-bis(dimethylamino) propane and DEI is N,N'-dicyclohexyl-1,2-ethanedi-imine] have been synthesized and characterized by single-crystal X-ray diffraction methods. We report herein the synthesis and crystal structure of the title compound (I).

In the molecule of the title compound, (I), (Fig. 1), the Fe^II atom is four-coordinated in distorted tetrahedral configurations by two N atoms from one 2, 2'-biquinoline and two terminal Cl atoms. The Fe—Cl and Fe—N bond lengths and angles (Table 1) are within normal range (X). In this complex, Fe—N average distance is 2.1029 (15)Å and the Fe—Cl average bond distance is 2.2303 (6) Å. The Fe—N average bond distances in high-spin Fe^II and Fe^III phenanthroline and bipyridine complexes are around 2.2 Å. However, low-spin Fe^II and Fe^III complexes, the Fe—N distances less than 2 Å were reported (Figgis et al., 1983; Kulkarni et al., 1998). Therefore, in the molecule of the title compound, the Fe—N bond distance is unambiguously high-spin Fe^II. It seems substitution in the 6 position of bipyridine is crucial to stabilize Fe^II high-spin versus (Fe^II) especially low-spin. Also, biquinoline result in auto reduce of Fe^III to Fe^II.

The π-π contacts between the pyridine rings, Cg2···Cg2ⁱ, Cg2···Cg4ⁱ, Cg3···Cg3ⁱⁱ, Cg3···Cg5ⁱ, Cg4···Cg4ⁱⁱ and Cg5···Cg3ⁱⁱ [symmetry cods: (i) 1-X, 1-Y, 1-Z, (ii) 1-X,-Y,1-Z, where Cg2, Cg3, Cg4 and Cg5 are centroids of the rings (N1/C1/C6—C9), (N2/C10—C13/C18), (C1—C6) and (C13—C18), respectively] further stabilize the structure, with centroid-centroid distance of 3.7611 (3), 3.7603 (4), 3.5292 (4), 3.5336 (5) and 3.6656 (4) Å, respectively. It seems this π-π stacking is effective in the stabilization of the crystal structure (Fig. 2).

Experimental

A solution of 2,2'-biquinoline (0.20 g, 0.78 mmol) in methanol (6 ml) and chloroform (2 ml) was added to a solution of FeCl₃.6H₂O (0.07 g, 0.26 mmol) in methanol (6 ml) and chloroform (2 ml) and the resulting yellow solution was stirred for 15 min at room temperature. This solution was left to evaporate slowly at room temperature. After two weeks, red blocks of (I) were isolated (yield 0.07 g, 70.3%).