Self-assembly of alkyl N-acetylglyoxylic amides of varying chain lengths

Abstract

Alkyl N-acetylglyoxylic amides have been synthesised from N-acetylisatins and their self-assembly studied in the solid state by X-ray crystallography. Different molecular conformations were observed for molecules 5a, 5b, 5d and 6b, which have a strong influence on their supramolecular organization in the crystals. Both strong and weak interactions played key roles in the self-assembly process and the formation of well-defined supramolecular architectures. Crystal structures of 5b revealed novel CO⋯CO (carbonyl–carbonyl) dipolar interactions involving three carbonyl groups and intermolecular halogen bonding interactions, either C–H⋯Br contacts with inclusion of cyclohexane in 5b-1 or Br⋯Br contacts without the inclusion of solvent in 5b-2.