Syntheses and characterisation of terephthalonitrile radical salts

Abstract

Two terephthalonitrile radical salts have been synthesized, isolated and characterized as Li+(tpn)●–(THF)2 and Na+(tpn)●–(THF) (tpn = terephtalonitrile; THF = tetrahydrofuran). Single crystal X-ray diffraction reveals that the lithium and sodium ions are bridged by tpn●– and further coordinated by THF solvent molecules, forming 1-D and 3-D coordination networks respectively. While the lithium salt exhibits paramagnetic behaviour, the sodium analogue is diamagnetic in the solid state due to strong π-π interactions between tightly stacked tpn●– pairs. These readily isolable radical salts are versatile precursors for cross-coupling reactions, mild organic reductants and could be used as attractive ligands for designing high temperature molecular magnets and conductive materials.