Crystal structure of 3,5-bis­(4-chloro­phen­yl)-1-propyl-1,3,5-tri­aza­cyclo­hexane

Leila Lefrada; Ahcene Bouchemma; Sofiane Bouacida; Nicolas Claiser; Mohamed Souhassou

doi:10.1107/S1600536814019060

. 2014 Aug 30;70(Pt 9):o1061–o1062. doi: 10.1107/S1600536814019060

Crystal structure of 3,5-bis(4-chlorophenyl)-1-propyl-1,3,5-triazacyclohexane

Leila Lefrada ^a,^b, Ahcene Bouchemma ^a,^b, Sofiane Bouacida ^c,^b,^*, Nicolas Claiser ^d, Mohamed Souhassou ^d

PMCID: PMC4186157 PMID: 25309226

Abstract

In the title molecule, C₁₈H₂₁Cl₂N₃, the triazacyclohexane ring adopts a chair conformation with both 4-chlorophenyl substituents in axial positions and the propyl group in an equatorial site. The dihedral angle between the planes of the benzene rings is 49.5 (1)°. In the crystal, molecules are arranged in a head-to-tail fashion, forming columns along [010], and pairs of weak C—H⋯π interactions form inversion dimers between columns.

Keywords: crystal structure, triazacyclohexane, C—H⋯π interactions

Related literature

For conformations of 1,3,5-triaryl derivatives of 1,3,5-triazacyclohexane, see: Baker et al. (1978 ▶); Bouchemma et al. (1989 ▶, 1990 ▶); Bushweller (1995 ▶); Kleinpeter et al. (2005 ▶); Duke et al. (1973 ▶); Gilardi et al. (2003 ▶); Giumanini et al. (1985 ▶); Latreche et al. (2006 ▶); Mloston et al. (2006 ▶); Freeman et al. (2005 ▶); Wiberg et al. (1999 ▶).

Experimental

Crystal data

C₁₈H₂₁Cl₂N₃
M _r = 350.28
Triclinic,
a = 6.0785 (3) Å
b = 10.3190 (6) Å
c = 14.4360 (8) Å
α = 91.570 (3)°
β = 91.946 (2)°
γ = 99.055 (3)°
V = 893.19 (8) Å³
Z = 2
Mo Kα radiation
μ = 0.37 mm⁻¹
T = 295 K
0.22 × 0.13 × 0.07 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (Blessing, 1995 ▶) T _min = 0.274, T _max = 0.467
13643 measured reflections
3448 independent reflections
2751 reflections with I > 2σ(I)
R _int = 0.016

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.142
S = 1.03
3448 reflections
209 parameters
H-atom parameters constrained
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Data collection: COLLECT (Nonius, 1997 ▶); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO (Otwinowski & Minor, 1997 ▶) and SCALEPACK; program(s) used to solve structure: SIR2002 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶) and DIAMOND (Brandenburg & Berndt, 2001 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536814019060/lh5723sup1.cif

e-70-o1061-sup1.cif^{(26.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814019060/lh5723Isup2.hkl

e-70-o1061-Isup2.hkl^{(165.6KB, hkl)}

Click here for additional data file.^{(6.4KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814019060/lh5723Isup3.cml

Click here for additional data file.^{(1.5MB, tif)}

. DOI: 10.1107/S1600536814019060/lh5723fig1.tif

The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level.

Click here for additional data file.^{(2.1MB, tif)}

. DOI: 10.1107/S1600536814019060/lh5723fig2.tif

Part of the crystal structure of the title compound showing the ’head to tail’ arrangement of molecules arranged in columns.

CCDC reference: 1020727

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg is centroid of C21–C26 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2A⋯Cg ⁱ	0.96	2.92	3.668 (3)	134

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work is supported by laboratory LCATM, Université Oum El Bouaghi, Algeria. Thanks are due to MESRS (Ministére de l’Enseignement Supérieur et de la Recherche Scientifique, Algeria) for financial support.

supplementary crystallographic information

S1. Comment

The conformational behaviour of substituted cyclohexanes as well as heterocyclohexanes has been the subject of numerous studies (Bushweller, 1995). The ring normally adopts the chair conformation unless specific intramolecular interactions stabilize the twist (Kleinpeter et al., 2005) or boat conformers (Freeman et al., 2005). Saturated six-membered rings are prevalent in organic chemistry. For cyclohexane, experimental and computational studies have established that the chair conformation is 5.5 kcal/ mol more stable than the twist form (Wiberg et al., 1999). N,N',N''-Trisubstituted 1,3,5-triazinanes are of interest as precursors for the preparation of different N-substituted imidazoles (Mloston et al., 2006). The heterocyclic nucleus is expected to adopt a chair conformation and four distinct patterns of substituent orientation have to be considered, eee, eea, eaa and aaa, where e = equatorial and a = axial, with each of the conformers having axial repulsions involving the substituents or lone pairs of electrons on the N atoms. Several 1,3,5-trialkyl derivatives have been investigated in solution by dipole moment measurements and the results interpreted in terms of the eee conformer, the eea conformer (Baker et al., 1978), and varying amounts of the eee, eea and eaa conformers (Duke et al., 1973). Various 1,3,5-triaryl-1,3,5-triazacyclohexanes adopt the diaxial-equatorial orientation of substituents in the solid state thus avoiding 1,3-diaxial lone-pair repulsions (Giumanini et al. 1985; Gilardi et al. 2003 Bouchemma et al. 1989; 1990).

In the present work, a new derivate (I) of triazacyclohexane is reported and molecular structure is shown in Fig. 1. The 1,3,5-triazacycolohexane ring is in a chair conformation which is typical of this ring (Gilardi et al. 2003). The stucture of a similar compound viz 1-propyl-3-5-bis-(4-fluorophenyl)-1,3,5- triazacycolohexane (II) has been reported (Latreche et al. 2006). In both (I) and (II) the heterocyclic rings adopt chair conformations with two fluorophenyl substituents situated in axial positions and a third group (propyl) equatorial. The dihedral angle between the benzene rings (C11-C16/C21-C26) is 49.5 (1)°. In the crystal, molecules are arranged in a 'head to tail' fashion forming columns along [010] (see Fig. 2) and pairs weak C—H···π interactions form inversion dimers between columns.

S2. Experimental

The title compound was obtained by mixing a 2:1:1 stoichiometric ratio of propylamine and 4-chloroaniline with formalin in ethanol (25 ml) at 293K. The resulting solution was evaporated on a rotary evaporator to dryness and the white residue was recrystallized from cyclohexane.