Spin-Crossover Behavior of Isomorphous Bi- and Mononuclear Iron(III) Complexes

Abstract

Abstract Isomorphous bi- and mononuclear iron(III) complexes, [FeIII2L2(bimb)](BPh4)2 (1) and [FeIIIL(meim)]BPh4 (2), where H2L = bis(3-methoxysalicylideneaminopropyl)amine, bimb = 1,4-bisimidazolylbutane, meim = N-methylimidazole, and BPh4− = tetraphenylborate, respectively, were synthsized. Binuclear complex 1 showed a two-step spin-crossover (SCO) behavior at T1⁄2=60 and 90 K, whereas mononuclear complex 2 showed a one-step SCO behavior at T1⁄2=215 K. The different SCO behavior can be ascribed to the quasi-one-dimensional structure constructed by π–π stacking and the binuclear structure.