Smaller is smarter in a new cobalt(II) imide: intermolecular interactions involving pyrazine versus the larger aromatic quinoxaline

Abstract

<div><p>The synthesis of one symmetric and one non-symmetric ligand based on imide, quinoxaline and pyrazine moieties are reported. The symmetric ligand, <i>N</i>-(2-quinoxalylcarbonyl)-2-quinoxalinecarboxamide (H<b>quinoxquinox</b>), is structurally characterised as H<b>quinoxquinox</b>·d₆DMSO. The non-symmetric ligand, <i>N</i>-(2-pyrazylcarbonyl)-2-quinoxalinecarboxamide (H<b>Lquinoxpz</b>), was used to prepare the cobalt(II) complex [Co^II(<b>quinoxpz</b>)₂]·CH₃OH, which was observed to remain high spin at 90 K. The structures of H<b>Lquinoxquinox</b>·d₆DMSO and [Co^II(<b>quinoxpz</b>)₂]·CH₃OH are evaluated with regard to their potential to produce spin crossover (SCO) behaviour and for the construction of three-dimensional coordination polymers.</p></div