Synthesis, crystal structure and magnetic properties of a novel one-dimensional nickel(III) chain complex showing ferromagnetic ordering at low temperature

A novel ferromagnetic complex [BrFBzPy][Ni( mnt)(2)], where [BrFBzPy](+) = 1-(4'-bromo-2'-fluorobenzyl) pyridinium and mnt(2-) = maleonitriledithiolate, has been prepared and characterized. In the crystal structure the most prominent feature is that the [Ni(mnt)(2)](-) anions and [BrFBzPy](+) cations form a well-separated stacking column along the c-axis, within which the [Ni(mnt)(2)](-) anions are uniformly spaced to give a one-dimensional (1-D) chain structure. The magnetic properties of this complex have been investigated in the temperature range 1.8-300 K and its magnetization studies show there exists ferromagnetically coupled interactions within the [Ni(mnt)(2)](-) anion chain (J = 42.2 cm(-1)), and antiferromagnetically coupled interactions between [Ni(mnt)(2)](-) anion chains (J(eff) = -4.78cm(-1)). The temperature dependences of the ac susceptibility revealed that this 1- D chain system is ferromagnetically ordered around 2 K and chi(ac) measurements performed at different magnetic fields and frequencies suggest that there may coexist a degree of spin glass behaviour at low temperature.