Molecular switching in iron complexes bridged via tin-cyanides observed by Mössbauer and ESR spectroscopy

Abstract

The precursor [FeIII(L)Cl] (LH2 N,N'-bis(2'-hydroxy- 3'-X-benzyliden)-1,6-diamino-3-N-hexane) is a high-spin (S 5/2) complex (with X -CH3, -O-CH3). This precursor is combined with the bridging unit [SnIV(CN)4] to yield star-shaped pentanuclear clusters, [(L-X-FeIII)4Sn(CN) 4]Cl4 57Fe-Mössbauer, 119mSn- Mössbauer, and ESR spectroscopy are used to study our samples. For X -CH3 the 57Fe-Mössbauer data show a multiple spin transition between iron(III) in the high-spin and low-spin state. Changing the functional group from X -CH3 to X -O-CH3 turns the switchability off.