Ferromagnetic dinuclear copper(II) complex based on bridging oxalate and bipyridinium ligands

A photoelectrochemically active bipyridinium salt, N-(2-pyrazinyl)-4,4′-bipyridinium chloride (PrBpyCl), and its copper complex [Cu2(PrBpy)2(C2O4)3] · 4H2O (1) have been synthesized and structurally characterized. The complex consists of oxalate-bridged dinuclear Cu(II) units, which are held together through π–π stacking and hydrogen bonding interactions to yield 3D supramolecular framework. The temperature-dependent magnetic susceptibility measurements indicate the existence of a weak ferromagnetic coupling between Cu(II) ions.