Synthesis, structure and magnetic properties of two organically-templated coordination polymers, {[EDAH2][M1M2F2(SO4)2(H2O)2]}n (M1=M2=NiII and M1=CoII, M2=NiII)

Two isostructural, organically-templated, 2D coordination polymers, one containing NiII and another containing CoII and NiII ions with the general formulae, {[EDAH2][M1M2F2(SO4)2(H2O)2]} n , (EDA=ethylenediamine, M1 =M2 =NiII (1), and M1 =CoII, M2 =NiII (2)) have been synthesized and structurally characterized. 1 and 2 consist of a 1D chain bridged by F− ion, [M–F–M] n which is interconnected by SO4 2− tetrahedra forming a 2D [Ni2F2(SO4)2(H2O)2] n 2− or [CoNiF2(SO4)2(H2O)2] n 2− corrugated sheet which are templated by diprotonated ethylenediamine [EDAH2] cation. Temperature-dependent magnetic measurements reveal the presence of spin-canted antiferromagnetism in both 1 and 2. 1 behaves like a soft magnet with a small magnetic hysteresis with a coercive field (Hc ) of 0.46kOe and a remnant magnetization (MR ) of 0.09 μ B. 2, on the other hand exhibits relatively a hard magnet like behavior with large magnetic hysteresis with Hc =8.74kOe and MR =0.76 μ B. The difference in magnetic behaviors of 1 and 2 is attributed to the difference in single-ion magnetic anisotropy and spin magnitudes of NiII (S =1) and CoII (S =3/2) ions.