Crystal structure of 4-(1H-indol-3-yl)-2-(4-methoxyphenyl)-6-phenylpyridine-3-carbonitrile

In the title compound, C27H19N3O, the dihedral angles between the plane of the pyridine ring and those of the indole (r.m.s. deviation = 0.018 Å), phenyl and methoxybenzene substituents are 33.60 (6), 25.28 (7) and 49.31 (7)°, respectively. The N atom of the carbonitrile group is significantly displaced [0.288 (2) Å] from the plane of the pyridine ring, perhaps due to steric crowding. In the crystal, inversion dimers linked by pairs of N—H⋯Nn (n = nitrile) hydrogen bonds generate R 2 2(16) loops. Aromatic π–π stacking [centroid–centroid separation = 3.6906 (7) Å] and very weak C—H⋯π interactions are also observed".


S1. Comment
Derivatives of 3-cyanopyridine are important and useful intermediates in preparing a varity of heterocyclic compounds (Shishoo et al., 1983). Therefore, the synthesis of 3-cyanopyridine derivatives attracts much interest in organic chemistry.
It was in this context that the title compound, was investigated.
The deviation of the nitrile atoms (C41,N2) from the mean plane of the pyridine ring system is -0.1497 (1) Å and The crystal structure features an N-H···N interaction between inverse related molecules generating a graph set ring motif R 2 2 (16) which are linked into chains through C-H···Cg1 interation (Cg1 is the centroid of the pyrrole ring of the indole moiety) and by π···π stacking interaction involving adjacent pyridine rings of the symmetry related molecule at (1-X,1-Y,-Z), with a centroid-to-centroid distance of 3.6906 (7) Å· (Fig 2).

S3. Refinement
H atoms were placed at calculated positions and allowed to ride on their carrier atoms with C-H = 0.93-0.98 Å and with U iso = 1.2U eq (C, N) for N, CH 2 and CH atoms and U iso = 1.5U eq (C) for CH 3 atoms.

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.