Acta Cryst. (2014). C70, 236-240 [ doi:10.1107/S2053229614000291 ]
Abstract: The structures of three new pyridine derivatives, 2-methoxy-4-(4-methoxyphenyl)-5,6,7,8,9,10-hexahydrocycloocta[b]pyridine-3-carbonitrile, C20H22N2O2, (I), 2-ethoxy-4-(3-nitrophenyl)-5,6,7,8,9,10-hexahydrocycloocta[b]pyridine-3-carbonitrile, C20H21N3O3, (II), and 2-ethoxy-4-(4-methoxyphenyl)-5,6,7,8,9,10-hexahydrocycloocta[b]pyridine-3-carbonitrile, C21H24N2O2, (III), differ in the nature of the substituents either at the 2-position of the central pyridine ring or on the pendent aryl ring. This simple change in the structure substantially alters the intermolecular interaction patterns. The substituted phenyl group adopts a synclinal geometry with respect to the plane of the pyridine ring in all three compounds. In (I), a C-HN interaction results in a one-dimensional chain parallel to the b axis. In (II), there are two C-HN(nitrile) interactions from different symmetry-related molecules, resulting in a two-dimensional network parallel to the bc plane. There is also a weak C-HO interaction from the ethoxy group to an adjacent nitro O atom. The present work is an example of how the simple replacement of a substituent in the main molecular scaffold may transform the structure type, paving the way for a variety of supramolecular motifs and consequently altering the complexity of the intermolecular interaction patterns.
Formula: C20H22N2O2, C20H21N3O3 and C21H24N2O2
Keywords: crystal structure; cycloalkenopyridine structures; hydrogen bonding.
Structure factor file (CIF format) (159.2 kbytes)
Structure factor file (CIF format) (163.3 kbytes)
Structure factor file (CIF format) (168.3 kbytes)
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