Crystal structures of (E)-2-(2-benzylidenehydrazinyl)quinoxalines: persistent N-H•••N intermolecular hydrogen bonds but variable π•••π interactions.

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Abstract

The crystal structures of two (E)-2-(2-benzylidenehydrazin-1-yl)quinoxaline derivatives, (E)-2-(XYC₆ H₃-CH=N-NH)-quinoxalines, 1, namely (1: X=H; Y=4-MeO or 4-O₂ N) have been determined. In both cases, the major intermolecular interactions are N–H···N(pyrazine) hydrogen bonds. While in both compounds π···π intermolecular stacking interactions are present, these involve different aromatic rings in each case and hence different structural motifs are formed. These findings – of persistent and dominant N–H···N(pyrazine) hydrogen bonds and variable π···π interactions – concur with the previous findings for other compounds 1. The substituents, Y, in (1: X=H; Y=4-MeO or 4-O₂ N) play minor roles in the overall supramolecular arrangements.

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Keywords: π···π Interactions; crystal structures; hydrazones; N–H···N Hydrogen bonds; quinoxaline derivatives Document Type: Research Article DOI: http://dx.doi.org/10.1515/zkri-2014-1769   Publication date: 5 de Agosto de 2014