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 SO42− tetrahedra forming a 2D [Ni2F2(SO4)2(H2O)2]n2− or [CoNiF2(SO4)2(H2O)2]n2− 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 0.46 kOe and a remnant magnetization (MR) of 0.09 μB. 2, on the other hand exhibits relatively a hard magnet like behavior with large magnetic hysteresis with Hc = 8.74 kOe and MR = 0.76 μB. 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.

Graphical abstractTwo 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. Magnetic measurements reveal canted antiferromagnetism in both 1 and 2 and difference in hysteresis is attributed to the difference in single-ion magnetic anisotropy and spin magnitudes of NiII (S = 1) and CoII (S = 3/2) ions.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Organically-templated, 2D coordination polymers of Ni(II) and Co(II)/Ni(II). ► Spin-canted antiferromagnetism. ► Soft magnet for Ni(II) compound. ► Hard magnet for mixed metal Co(II)/Ni(II) compound. ► Single-ion magnetic anisotropy and spin magnitudes.