Spin‐Crossover Iron(II) Compounds with Pendent Tetraphenylethylene Group

Abstract

Two iron(II) compounds with the general formula of [Fe(phen‐TPE)2(NCX)2] ⋅ Y (phen‐TPE=3‐(tetraphenylethylene)‐1,10‐phenanthroline; X=S and Y=2DMF for 1 ⋅ 2DMF; X=Se and Y=DMF for 2 ⋅ DMF) were synthesized and characterized by single‐crystal X‐ray crystallography and magnetic measurements. Both compounds exhibited thermal‐induced complete one‐step spin‐crossover (SCO) behavior with the critical transition temperatures of 210 K and 260 K for 1 ⋅ 2DMF and 2 ⋅ DMF, respectively. The SCO behavior of these two isomorphic compounds depended significantly on robust intermolecular π⋅⋅⋅π interactions, NCX− groups and solvent molecules.