Acta Cryst. (2013). C69, 1177-1180 [ doi:10.1107/S0108270113023792 ]
Abstract: The title compounds, 3,5,7-triphenyl-1,2-diazacyclohepta-1(7),2-diene, C23H20N2, (I), and 3,7-bis(2-hydroxyphenyl)-5-phenyl-1,2-diazacyclohepta-1(7),2-diene, C23H20N2O2, (II), constitute the first structurally characterized examples of seven-membered heterocycles with 1,2-diaza ring N atoms. Compound (I) crystallizes in the space group P, with two independent molecules in the asymmetric unit that differ in the conformation of one of the phenyl rings, while (II) crystallizes in the space group C2/c. The C5N2 ring in each of (I) and (II) adopts a twist-boat conformation. Compound (I) exhibits neither C-H interactions nor - stacking interactions, whereas (II) shows both intramolecular O-HN hydrogen bonds and a C-H interaction that joins the molecules into an infinite chain in the  direction.
Formula: C23H20N2 and C23H20N2O2
Keywords: Seven-membered ring; nitrogen-containing heterocycle; conformational analysis; 1,5-diketone.
Structure factor file (CIF format) (398.3 kbytes)
Structure factor file (CIF format) (158.3 kbytes)
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