A spin-state switchable MOF-based film for visual DMSO vapor sensing

Abstract

The design of new colorimetric sensors for the detection of volatile organic compounds (VOCs) is of high interest due to the health issues they can induce. In this study, we report the fabrication of a film composed of the spin crossover complex [Fe(Sal₂trien)]NO₃ embedded within metal–organic framework nanocrystals. This composite material demonstrates a selective and reversible colorimetric response to dimethyl sulfoxide (DMSO) vapor exposure at room temperature, which is attributed to a spin state switching from high-spin (HS) to low-spin (LS) of the Fe(III) centers upon DMSO adsorption (down to 15 ppm_V). This work highlights the potential of integrating spin crossover complexes into MOFs to develop colorimetric and reusable VOC vapor sensors.