Crystal structures of 4-chloropyridine-2-carbo¬nitrile and 6-chloropyridine-2-carbonitrile exhibit different intermolecular n-stacking, C—H⋯Nnitrile and C

Insights: Publications Crystal structures of 4-chloropyridine-2-carbo¬nitrile and 6-chloropyridine-2-carbonitrile exhibit different intermolecular n-stacking, C—H⋯Nnitrile and C—H⋯Npyridine interactions

Acta Cryst. E71, 852

June 27, 2015

Written by Thomas J. O'Connor, Ph.D.

The two title compounds are isomers of C₆H₃ClN₂ containing a pyridine ring, a nitrile group, and a chloro substituent. The molecules of each compound pack together in the solid state with offset face-to-face π-stacking, and intermolecular C—H⋯N_nitrile and C—H⋯N_pyridine interactions. 4-Chloropyridine-2-carbonitrile, (I), exhibits pairwise centrosymmetric head-to-head C—H⋯N_nitrile and C—H⋯N_pyridine interactions, forming one-dimensional chains, which are π-stacked in an offset face-to-face fashion. The intermolecular packing of the isomeric 6-chloropyridine-2-carbonitrile, (II), which differs only in the position of the chloro substituent on the pyridine ring, exhibits head-to-tail C—H⋯N_nitrile and C—H⋯N_pyridine interactions, forming two-dimensional sheets which are π-stacked in an offset face-to-face fashion. In contrast to (I), the offset face-to-face π-stacking in (II) is formed between molecules with alternating orientations of the chloro and nitrile substituents.