Hexaazatriphenylenehexacarboxamide Solvate Exhibiting π-Complexation in the Solid State

Abstract

1,4,5,8,9,12-Hexaazatriphenylene-2,3,6,7,10,11-hexacarboxamide [HAT-(amide)6], C18H12N12O6, has been crystallized from Me2SO/water solutions. The unit cell contains two HAT-(amide)6 molecules, four Me2SO molecules and one water molecule. The HAT-(amide)6 molecules are arranged in dimers having a one-half ring offset of the members which permits HOMO-LUMO overlap. The C and N atoms of the core rings of one member of these dimers are separated from the best least-squares plane of the core rings of the other member of the dimer by an average distance 3.31 (9) A, which is smaller than the sum of the relevant van der Waals radii and is consistent with the π-complexation described by Beeson, Fitzgerald, Gallucci, Gerkin, Rademacher & Czarnik [J. Am. Chem. Soc. (1994), 116, 4621–4622]. Adjacent dimers are separated by a mean distance 3.69 (9) A. Some of the amide hydrogen bonds act in concert with the π-complexation in the formation of the dimers. The bond lengths and angles of the HAT core are not uniform. The C-C bonds fall into two distinct groups with means of 1.457 (6) and 1.405 (10) A; the C-N bonds also fall into two distinct groups with means of 1.350 (2) and 1.322 (7) A. The 18 atoms comprising the HAT core have a mean deviation of 0.08 (5) A from the best least-squares plane describing the core. Dihedral angles between the amide-group planes and the least-squares plane of the HAT core range from 10 to 78°. The complex pattern of hydrogen bonding includes intermolecular N-H⋯O and N-H⋯N bonds as well as intra­molecular N-H⋯N interactions. Only one cyclic dimer hydrogen-bond is formed. Me2SO and water molecules are involved in the hydrogen-bonding scheme and act also to complete the packing around the HAT-(amide)6 molecules. The mean values of the 16 intermolecular N-H⋯O hydrogen bond parameters are: N⋯O 2.99 (19) A; H⋯O 2.02 (24) A, N-H⋯O 159 (15)°.