Reversible coordination-induced spin state switching in a nickel(ii) complex via a crystal-to-crystal transformation

Abstract

The recent upsurge in coordination-induced spin state switching (CISSS) reflects its application in the areas of switchable contrast agents for magnetic resonance imaging (MRI) and molecular spintronics. Here, an unprecedented CISSS behavior driven by a solvent desorption-triggered single-crystal-to-single-crystal (SCSC) deligation process is found in a dinuclear nickel(II) complex, [Ni₂(hbth)(py)₆]·2MeOH (1·py·MeOH), which is evidenced by the thermal stability, crystal structures, thermochromism and magnetic properties. Further experiment of vapor diffusion leads to the reversible crystal transformation accompanied with optical (spectral) and magnetic responses in cycles, which provides a new strategy for developing external-stimuli CISSS materials.