Authors: Baddeley, T.C.; Howie, R.A.; Lima, C.H.S.; Kaiser, C.R.; De Souza, M.V.N.; Wardell, J.L.; Wardell, S.M.S.V.
AbstractThe crystal structures of seven (pyrazinecarbonyl)hydrazone mono-halo-benzaldehyde derivatives, N2C4H3CONHN=CHC6H4X (X = F, Cl or Br) are reported. In all cases, hydrogen-bonds link the planar molecules edge to edge to form ribbons which are themselves essentially planar. These ribbons are then packed face to face in a variety of ways dependent upon the position and nature of the halogen substituent. In all of the structures the molecules are found in layers one molecule thick. For the chloro- and bromo-substituted compounds three distinct forms of two-dimensional connectivity in the layers is achieved by combination of π · · · π interactions with the ribbon hydrogen-bonds. For the fluoro- derivatives the ribbon hydrogen-bonds connect layers in which the two-dimensional connectivity is provided by the π · · · π interactions, in one case augmented by C–H · · · F and C–H · · · π bonds, resulting in complete three-dimensional connectivity.
Keywords: (Pyrazinecarbonyl)hydrazone; pi … pi interactions; Hydrogen bonds; Single crystal structure analysis; X-ray diffractionDocument Type: Research ArticleDOI: http://dx.doi.org/10.1524/zkri.2009.1182Publication date: 1 de Outubro de 2009