Spontaneous magnetization below 7.7 K based on an extended 3-D H-bonding network material: synthesis, crystal structure and magnetic properties

The structure of the complex [4-aminopyridinium][Ni(mnt)(2)], as determined by X-ray single crystal analysis, consists of 4- aminopyridinium cations and [Ni(mnt)(2)](-) anions. The interactions between anions and cations via the bifurcated N(Py)-H...NC H-bonds give rise to a 1-D zigzag chain of alternating cations and anions, and a 3-DH-bonding network through further N(NH2)-H...NC interactions chi(dc) and chi(ac) have been measured down to 1.8 K and analysed, indicating the existence of a spin canting phenomenon. Below the critical temperature (around 7.7 K), the sample spontaneously magnetizes, and the hysteresis loop was observed at 1.85 K, corresponding parameters are as follows: H-c = 150 Oe and M-r = 7.9 emu mol(-1). The pathway of the exchange interaction in this complex via H-bonding is discussed in light of the crystal structure analysis