Authors: Howie, R.A.; Lima, C.H.S.; Kaiser, C.R.; Silva, M.M.; De Souza, M.V.N.; Wardell, J.L.; Wardell, S.M.S.V.
Source: Zeitschrift für Kristallographie, v. 225, p. 245-252, 2010.
Publisher: De Gruyter
Abstract
The molecules of the (pyrazinecarbonyl)hydrazones of the heterocyclic aldehydes RCHO with R = pyrrol-2-yl, furan-2-yl, thien-2-yl and pyridin-2-yl corresponding to compounds (2: X = NH), (2: X = O), (2: X = S)and 3, respectively, are formally rather similar. Despite this the molecular packing and intermolecular interactions show unexpectedly wide variation throughout the series. In 2 hydrogen-bonds link the planar molecules edge to edge to form chains or, in one case, planar ribbons while 3 exhibits zig-zag chain connectivity. Three-dimensional connectivity is attained by intermolecular hydrogen-bonds alone in ortho-(2: X = S), the orthorhombic polymorph of (2: X = S)and by intermolecular hydrogen-bonds combined with π···π interactions in (2: X = O) and 3. No more than two-dimensional layer connectivity is found in (2: X = NH) and the monoclinic polymorph, mono-(2: X = S) of (2: X = S).Keywords: (pyrazinecarbonyl)hydrazone; π···π interactions; Hydrogen bonds Document Type: Research Article DOI: http://dx.doi.org/10.1524/zkri.2010.1248 Publication date: 1 de Junho de 2010
