The synthesis, characterization, X-ray structure and magnetism of dinuclear-based bis[μ-(1,1,3,3-tetracyano-2-ethoxypropenido-κN,N′) (1,1,3,3-tetracyano-2-ethoxypropenido-κN)(2,2′-bipyridine)copper(II)] organized in alternating chains via semi-coordinating Cu-N distances

The monoanionic ligand 1,1,3,3-tetracyano-2-ethoxypropenide (tcnoet) is reported with its Cu^II–bpy complex of formula [Cu₂(μ-tcnoet)₂(tcnoet)₂(bpy)₂]. The structure has been determined using X-ray diffraction and features an alternating chain with bridging tcnoet ligands. One ligand acts as a bidentate, dinucleating ligand with one short Cu–N and one medium Cu–N bond, whereas the other tcnoet is largely monodentate, albeit with a very weak interdimer Cu–N bond. Despite the arrangement in dinuclear units, further arranged into linear chains through the non-bridging tcnoet ligand, the compound shows no significant magnetic exchange, as deduced from magnetic susceptibility down to 4 K. Ligand-field, IR and EPR spectra in the solid state and in frozen solution are reported and are consistent with the overall structure.