Extending the family of hybrid layered fluoride perovskites

Abstract

The family of hybrid layered fluoride perovskites has been extended, based on the only previously reported example (enH2)MnF4 (en = 1,2-diaminoethane), to include further divalent transition metals and longer chain diamines. The compounds (enH2)BF4, (B = Co, Ni) and (bnH2)BF4, (bn = 1,4-diaminobutane, B = Mn, Co) adopt the same space group (P21/c) as (enH2)MnF4, whereas (pnH2)BF4, (pn = 1,3-diaminopropane, B = Mn, Co) adopt the space group Pnma. Key differences in these structure types are shown to depend on the parity of the number of carbon atoms in the linear amine, which may be considered a structure-directing agent. Magnetic measurements on selected samples indicate differences in magnetic order that can be understood in terms of both the transition metal and the molecular species. All samples exhibit antiferromagnetic correlations but can in some cases develop a canted spin ferromagnetic component due to anisotropic exchange interactions. An additional compound, (bn)Ni2F4, has also been isolated, which exhibits a unique layered structure with bn acting as a ligand rather than in cationic form