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

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