cis-Difluoridobis(1,10-phenanthroline)chromium(III) perchlorate monohydrate

Torben Birk; Jesper Bendix; Högni Weihe

doi:10.1107/S1600536808001153

. 2008 Jan 16;64(Pt 2):m369–m370. doi: 10.1107/S1600536808001153

cis-Difluoridobis(1,10-phenanthroline)chromium(III) perchlorate monohydrate

Torben Birk ^a,^*, Jesper Bendix ^a, Högni Weihe ^a

PMCID: PMC2960161 PMID: 21201326

Abstract

The title complex, [CrF₂(C₁₂H₈N₂)₂]ClO₄·H₂O, displays a slightly distorted octahedral coordination geometry around the central chromium(III) ion. The Cr environment is composed of a cis arrangement of two 1,10-phenanthroline [average Cr^III—N = 2.0726 (10) Å] and two fluoride [average Cr^III—F = 1.8533 (6) Å] ligands. The water molecule forms a hydrogen bond to fluorine in a neighbouring cation.

Related literature

For details of the general synthesis of amine-containing difluorido complexes of chromium(III), see: Glerup et al. (1970 ▶). For the structure of the analogous 2,2′-bipyridine complex, see: Yamaguchi-Terasaki et al. (2007 ▶). For related literature, see: Brenčič et al. (1981 ▶, 1987 ▶); Delavar & Staples (1981 ▶); Kaizaki & Takemoto (1990 ▶); Kane-Maguire et al. (1986 ▶).

Experimental

Crystal data

[CrF₂(C₁₂H₈N₂)₂]ClO₄·H₂O
M _r = 567.87
Triclinic,
a = 7.6930 (10) Å
b = 9.4640 (8) Å
c = 16.0610 (17) Å
α = 79.750 (7)°
β = 83.228 (12)°
γ = 88.115 (8)°
V = 1142.6 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.68 mm⁻¹
T = 122 (1) K
0.44 × 0.41 × 0.16 mm

Data collection

Nonius KappaCCD area-detector diffractometer
Absorption correction: Gaussian integration (Coppens, 1970 ▶) T _min = 0.794, T _max = 0.913
28606 measured reflections
4014 independent reflections
3851 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.031
wR(F ²) = 0.145
S = 1.41
4014 reflections
329 parameters
H-atom parameters constrained
Δρ_max = 0.79 e Å⁻³
Δρ_min = −0.51 e Å⁻³

Data collection: COLLECT (Nonius, 1999 ▶); cell refinement: COLLECT; data reduction: EvalCCD (Duisenberg et al., 2003 ▶); 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 global, I. DOI: 10.1107/S1600536808001153/wk2075sup1.cif

e-64-0m369-sup1.cif^{(21.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808001153/wk2075Isup2.hkl

e-64-0m369-Isup2.hkl^{(196.7KB, hkl)}

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

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

Cr1—F2	1.8444 (10)
Cr1—F1	1.8621 (10)
Cr1—N4	2.0566 (15)
Cr1—N2	2.0607 (15)
Cr1—N3	2.0797 (16)
Cr1—N1	2.0934 (15)

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F2—Cr1—F1	95.92 (5)
F2—Cr1—N4	92.33 (5)
F1—Cr1—N4	91.42 (5)
F2—Cr1—N2	91.83 (6)
F1—Cr1—N2	91.86 (5)
N4—Cr1—N2	174.40 (5)
F2—Cr1—N3	89.38 (5)
F1—Cr1—N3	170.08 (5)
N4—Cr1—N3	79.95 (6)
N2—Cr1—N3	96.36 (6)
F2—Cr1—N1	170.54 (5)
F1—Cr1—N1	88.67 (5)
N4—Cr1—N1	95.83 (6)
N2—Cr1—N1	79.72 (6)
N3—Cr1—N1	87.34 (6)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5B⋯F1ⁱ	1.03	1.69	2.7183 (19)	175

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors are grateful to Mr Flemming Hansen (Centre of Crystallographic Studies, University of Copenhagen) for collection of the X-ray diffraction data.

supplementary crystallographic information

Comment

Difluoro complexes of chromium(III) with various amine ligands have received a steady interest in the literature. Areas of interest have been e.g. kinetic behavior (Delavar & Staples, 1981), solvatochromism (Kaizaki & Takemoto, 1990) and photochemical/photophysical properties (Kane-Maguire et al., 1986). From a synthetic point of view simple fluoro containing complexes exhibit some advantageous properties for synthesis in non-acidic media. The strong coordination of the small and basic fluoro ligand makes it suitable as an "inorganic" protection group, easily removed and substituted by other ligands. Only a limited number of complexes belonging to this group have been structural characterized e.g. cis-[Cr(NH₃)₄F₂]ClO₄ (Brenčič et al., 1981), cis-[Cr(en)₂F₂]ClO₄^. NaClOO₄^. H₂O (Brenčič et al., 1987) and cis-[Cr(bipy)₂F₂]ClO₄ (Yamaguchi-Terasaki et al., 2007). In this report we present the crystal structure of cis-Difluoro(1,10-phenanthroline)chromium(III) perchlorate monohydrate (1).

The structure of (1) shows a octahedral coordination geometry around the central chromium(III) ion consisting of a cis arrangment of two fluorine and two nitrogen ligator atoms (Figure 1). Comparison of the Cr—N bond distances in trans position relative to the fluoro ligand [N₁: 2.0934 (15) Å and N₃: 2.0797 (16) Å] show a slightly elongation compared to the corresponding in cis postion [N₂: 2.0607 (15) Å and N₄: 2.0566 (15) Å]. This pattern of bond lengths are similar to that found in the analogous bipyridine complex cis-Difluoro(2,2'-bipyridine)chromium(III) perchlorate, cis-[Cr(bipy)₂F₂]ClO₄.

The overall crystal packing is predominately determined by the approximately perpendicular orientation of the two planar 1,10-phenanthroline ligands [N₃—Cr—N₁:87.34 (6) °, N₃—Cr—N₂: 96.36 (6) °] and the presence of crystal water connecting each asymmetric unit with another through hydrogen bonding from water to fluorine (Figure 2).

Experimental

The title complex was synthesized by reflux of trans-difluorotetrakis(pyridine)chromium(III) perchlorate and 1,10-phenanthroline in 2-methoxyethanol according to the published method (Glerup et al., 1970).

Crystal suitable for X-ray diffraction were obtained by the following method: 0.208 g of the compound was dissolved in a solution of water/acetonitrile (20 ml/10 ml) and filtered though a filter paper into a small beaker. The beaker was covered with a lid of paper and left undisturbed at room temperature for crystallization (ca 3–5 days). The crystals was harvested by gently scratching with a spatula and washed with the mother liquid.