Ferromagnetic interactions in copper(II) and nickel(II) coordination polymers containing nitronyl nitroxide radical and terephthalate

Two new complexes [Cu(NITmPy)2(tp)] 1 and [Ni(NITmPy)2(tp)(H2O)2] 2 (NITmPy=2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and tp=terephthalato dianion) were synthesized and structurally and magnetically characterized. The structure of 1 is a neutral infinite chain where Cu(NITmPy)2 units are linked by terephthalate ligands. In complex 2, the 1-D chains of Ni(NITmPy)2 (H2O)2 units connected by tp develop into 2-D network via hydrogen bond interactions. The magnetic properties of 1 and 2 have been investigated in the temperature range 2–300 K. Both complexes exhibit ferromagnetic coupling and antiferromagnetic interactions dominate at low temperature. The magnetic behavior is discussed based on their structures.