Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover Fe^III Complex into Bimetallic Oxalate‐Based Ferromagnets

Abstract

Abstract The syntheses, structures and magnetic properties of the compounds of formula [Fe III (sal 2 ‐trien)][Mn II Cr III (ox) 3 ]⋅CH 2 Cl 2 ( 1 ; H 2 sal 2 ‐trien= N , N′ ‐disalicylidenetriethylenetetramine, ox=oxalate), [Fe III (sal 2 ‐trien)][Mn II Cr III (ox) 3 ]⋅CH 3 OH ( 2 ), [In III (sal 2 ‐trien)][Mn II Cr III (ox) 3 ]⋅0.25 H 2 O ⋅0.25 CH 3 OH⋅0.25 CH 3 CN ( 3 ), and [In III (sal 2 ‐trien)][Mn II Cr III (ox) 3 ]⋅CH 3 NO 2 ⋅0.5 H 2 O ( 4 ) are reported. The structure of 1 presents a 2D honeycomb anionic layer formed by Mn II and Cr III ions linked through oxalate ligands and a cationic layer of [Fe(sal 2 ‐trien)] + complexes intercalated between the 2D oxalate network. The structures of 2 , 3 , and 4 present a 3D achiral anionic network formed by Mn II and Cr III ions linked through oxalate ligands with [Fe(sal 2 ‐trien)] + or [In(sal 2 ‐trien)] + complexes and solvent molecules intercalated within the 3D oxalate network. The magnetic properties and Mössbauer spectroscopy of 1 and 2 indicate that these compounds undergo a long‐range ferromagnetic ordering at around 5 K and a spin crossover of the intercalated [Fe(sal 2 ‐trien)] + complexes above 130 K, which is complete in the case of 1 . The magnetic properties of the compounds 3 and 4 confirm the ferromagnetic ordering of the bimetallic oxalate network.