2,9-Bis(trichloro­meth­yl)-1,10-phenanthroline

Hoong-Kun Fun; Suchada Chantrapromma; Annada C Maity; Shyamaprosad Goswami

doi:10.1107/S1600536810002035

. 2010 Jan 23;66(Pt 2):o424. doi: 10.1107/S1600536810002035

2,9-Bis(trichloromethyl)-1,10-phenanthroline¹

Hoong-Kun Fun ^a,^*,^‡, Suchada Chantrapromma ^b,^§, Annada C Maity ^c, Shyamaprosad Goswami ^c

PMCID: PMC2979670 PMID: 21579839

Abstract

The asymmetric unit of the title compound, C₁₄H₆Cl₆N₂, contains two crystallographically independent molecules, each of which is slightly twisted from planarity. The dihedral angles between the central ring and the two outer rings are 3.81 (7) and 4.30 (7)° in one molecule, and 4.13 (8) and 4.10 (7)° in the other. In the crystal structure, molecules are interlinked by C—Cl⋯Cl interactions into sheets parallel to the ac plane. These sheets are stacked along the b axis in such a way that the molecules are antiparallel; they are further connected into a supramolecular network. There are no classical hydrogen bonds. C⋯Cl [3.637 (2) Å], Cl⋯Cl [3.5639 (5)–3.6807 (8) Å] and Cl⋯N [3.3802 (15)–3.4093 (15) Å] short contacts and π–π interactions, with centroid–centroid distances in the range 3.5868 (9)–3.7844 (9) Å, are observed.

Related literature

For reference bond-length data, see: Allen et al. (1987 ▶). For background to and applications of 1,10-phenanthroline derivatives, see: Armaroli et al. 1992 ▶); Beer et al. (1993 ▶); Emmerling et al. (2007 ▶); Goswami et al. (2007 ▶); Wesselinova et al. (2009 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₄H₆Cl₆N₂
M _r = 414.91
Monoclinic,
a = 24.3001 (6) Å
b = 6.8825 (2) Å
c = 20.3461 (5) Å
β = 114.689 (1)°
V = 3091.74 (14) Å³
Z = 8
Mo Kα radiation
μ = 1.11 mm⁻¹
T = 100 K
0.59 × 0.36 × 0.10 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.561, T _max = 0.898
63570 measured reflections
13520 independent reflections
9474 reflections with I > 2σ(I)
R _int = 0.054

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.105
S = 1.06
13520 reflections
397 parameters
H-atom parameters constrained
Δρ_max = 0.60 e Å⁻³
Δρ_min = −0.54 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810002035/wn2373sup1.cif

e-66-0o424-sup1.cif^{(26.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810002035/wn2373Isup2.hkl

e-66-0o424-Isup2.hkl^{(660.9KB, hkl)}

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

Acknowledgments

SG and ACM thank the Indian Government for financial support. SC thanks the Prince of Songkla University for financial support through the Crystal Materials Research Unit. The authors also thank the Malaysian Government and Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

supplementary crystallographic information

Comment

Trichloromethyl-substituted heterocyclic compounds are of great importance due to their broad spectrum of biological activities. 2,9-Bis(trichloromethyl)-1,10-phenanthroline is used as a potentially robust ligand for metal oxidation catalysts (Beer et al., 1993). 1,10-phenanthroline derivatives also show antitumor (Wesselinova et al., 2009) as well as luminescence properties (Armaroli et al., 1992). Recently a series of trichloromethyl-substituted heterocyclic compounds has been synthesized (Goswami et al., 2007) in good yield using N-chlorosuccinimide (NCS) and triphenylphosphine (PPh₃) in carbon tetrachloride. In supramolecular chemistry it is known that the self-association of individual molecules can lead to the formation of highly complex and fascinating supramolecular aggregates if halogen···π interactions contribute to the formation of specific motifs (Emmerling et al., 2007). The title compound was synthesized in order to study its supramolecular structure.

The asymmetric unit (Fig. 1) contains two molecules, A and B, having slight differences in bond lengths and angles. The 1,10-phenanthroline unit is not strictly planar, with dihedral angles between the central ring and the C1–C4/C12/N1 and C7–C11/N2 rings of 3.81 (7) and 4.30 (7)°, respectively, for molecule A [the corresponding values for molecule B are 4.13 (8) and 4.10 (7)° ]. In both molecules, A and B, none of the Cl atoms of the trichloromethyl substitutent is coplanar with the 1,10-phenanthroline ring system. The bond distances adopt normal values (Allen et al., 1987).

In the crystal structure (Fig. 2), non-covalent interactions play a significant role in the three-dimensional supramolecular architecture, in which the molecules are interlinked into sheets parallel to the ac plane. These sheets are stacked along the b axis in such a way that the molecules are antiparallel. These sheets are further connected into a supramolecular network. There are no classical hydrogen bonds. However, C···Cl [3.637 (2) Å], Cl···Cl [3.5639 (5)–3.6807 (8) Å] and Cl···N [3.3802 (15)–3.4093 (15) Å] short contacts are present. π–π interactions are also observed, with distances of Cg₁···Cg₂ⁱ = 3.6610 (9) Å, Cg₁···Cg₂ⁱⁱ = 3.5868 (9) Å, Cg₁···Cg₃ⁱ = 3.7331 (10) Å, Cg₂···Cg₃ⁱⁱ = 3.7845 (9) Å, Cg₄···Cg₅ⁱⁱⁱ = 3.5949 (9) Å, Cg₄···Cg₅^iv = 3.6404 (9) Å, Cg₄···Cg₆ⁱⁱⁱ = 3.7417 (10) Å and Cg₅···Cg₆^iv = 3.7198 (9) Å (symmetry codes: (i) 1 - x, 1 - y, 1 - z; (ii) 1 - x, 2 - y, 1 - z; (iii) 2 - x, -y, 1 - z and (iv) 2 - x, 1 - y, 1 - z). Cg₁, Cg₂, Cg₃, Cg₄, Cg₅ and Cg₆ are the centroids of the rings C1A–C4A/C12A/N1A, C7A–C11A/N2A, C4A–C7A/C11A–C12A, C1B–C4B/C12B/N1B, C7B–C11B/N2B and C4B–C7B/C11B–C12B, respectively.

Experimental

A mixture of N-chlorosuccinimide (500 mg, 4.5 mmol) and triphenylphosphine (500 mg, 4.2 mmol) was moistened with CCl₄ (60 ml) in a round bottom flask and stirred at room temperature for 25 min. A solution of 2,9-dimethyl-1,10-phenanthroline (1 g, 5.2 mmol) was added to the suspension and the reaction mixture was stirred and heated under reflux for 7 h. The solution was cooled and filtered. The evaporated filtrate was washed with saturated aqueous Na₂CO₃ and extracted repeatedly with CHCl₃. Drying over anhydrous Na₂SO₄ was carried out, and the solvent was removed under reduced pressure. The crude product was purified with SiO₂ chromatography (eluted with 1% ethyl acetate in petroleum ether) to give the title compound as a white crystalline solid. Colorless plate-shaped single crystals suitable for X-ray structure determination were recrystalized from CH₂Cl₂:hexane (1:10, v/v) by slow evaporation of the solvent at room temperature over the course of a week.