2D and 3D bimetallic oxalate-based ferromagnets prepared by insertion of different FeIII spin crossover complexes

Abstract

The syntheses, structures and magnetic properties of the compounds of formula [Fe^III(5-NO₂sal₂-trien)][Mn^IICr^III(ox)₃]·CH₃NO₂·0.5H₂O (1) and [Fe^III(5-CH₃Osal₂-trien)][Mn^IICr^III(ox)₃] (2) are reported. The structure of 1, that crystallizes in the P2₁ chiral space group, presents a 2D honeycomb anionic layer formed by Mn^II and Cr^III ions linked through oxalate ligands and a cationic layer of [Fe^III(5-NO₂sal₂-trien)]⁺ complexes intercalated between the 2D oxalate network. The structure of 2, that crystallizes in the Pna2₁ acentric space group, presents a 3D achiral anionic network formed by Mn^II and Cr^III ions linked through oxalate ligands with [Fe(5-CH₃Osal₂-trien)]⁺ complexes intercalated within the 3D oxalate network. The magnetic properties of 1 and 2 indicate that both compounds undergo a long-range ferromagnetic ordering at ca. 5 K. On the other hand, the inserted Fe^III cations remain mainly in the low-spin (LS) state in the case of 1 and in the high-spin (HS) state in the case of 2.