(4E)-N-[(2-Bromophenyl)methoxy]-1,3-dimethyl-2,6-diphenylpiperidin-4-imine

In the title compound, C26H27BrN2O, the piperidine ring has a chair conformation and all ring substituents occupy equatorial positions, apart from the double-bonded N atom, which occupies a bisectional position. The dihedral angle formed between the phenyl rings is 61.18 (19)°, and the phenyl rings form dihedral angles of 49.78 (19) and 69.2 (18)° with the bromobenzene ring. The latter is coplanar with the methoxy(methylidene)amine fragment [N—O—C—C torsion angle = −171.7 (2)°]. Linear supramolecular chains, approximately along [112], sustained by C—H⋯π interactions, feature in the crystal packing.


Experimental
Cg1 is the centroid of the C21-C26 benzene ring.

Comment
The original synthesis (Ramalingan et al., 2006) of the title compound, (I), was motivated by the diverse range of molecules possessing a 2,6-diarylpiperidine core that exhibit potent biological activities (Ramachandran et al., 2011;Ramalingan et al., 2004). Herein, the crystal and molecular structure of (I) is described.
In (I), Fig. 1, the piperidine ring has a chair conformation and all ring-substituents bound to C occupy equatorial positions, as found for the chloro derivative (Ramalingan et al., 2012), but the the double bonded N atom occupies a bisectional position. The dihedral angle formed between the C15-C20 and C21-C26 phenyl rings is 61.18 (19)°, and each forms a dihedral angle of 49.78 (19) and 69.2 (18)°, respectively, with the bromobenzene ring, which occupies a position co-planar to the methoxy(methylidene)amine residue as seen in the N1-O1-C7-C6 torsion angle of -171.7 (2)°. This is in contrast to the orthogonal disposition in the chloro derivative (Ramalingan et al., 2012). The conformation about the imine C8═N1 bond [1.281 (4) Å] is E.
In the crystal packing, linear supramolecular chains are formed via C-H···π interactions, Fig. 2 and Table 1. These assemble into layers parallel to (1 0 1) and stack without specific intermolecular interactions between the chains, Fig. 3.

Experimental
For full details of the synthesis, refer to Ramalingan et al. (2006). Re-crystallization was performed by slow evaporation of an ethanolic solution of (I) which afforded colourless crystals. M.pt: 378-378 K.

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H = 0.95-0.99 Å, U iso (H) = 1.2-1.5U eq (C)] and were included in the refinement in the riding model approximation. Owing to poor agreement, a reflection, i.e. (-6 4 9), was omitted from the final refinement.  The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 70% probability level.

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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 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 (Å 2 )
x y z U iso */U eq