In
microporous materials, the guest species interacts with the
host framework and can modify the electronic structure of that last
one and the related physical and functional properties. For instance,
this possibility is relevant regarding their potential applications
in sensor and actuator device construction. In this contribution,
we are reporting the effect of tiny aromatic molecules (benzene, toluene,
furan, and thiophene) adsorption in Fe(pyrazine)[Fe(CN)5NO]. This material has a porous framework appropriate for the adsorption
of small molecules, and at the same time, it shows spin crossover
properties. TG mass spectrometry and IR spectroscopy followed the
presence of these molecules as adsorbed species in the host framework.
The results from XRD structural studies, IR and Mössbauer spectra,
and magnetic (SQUID) measurements illustrate the modification of the
spin crossover properties of that solid through the adsorption process
of these tiny molecules. The recorded experimental data shed light
on the framework adsorption sites for these guest molecules and the
nature of the guest–host interactions. The effects of the guest
molecule on the spin crossover properties of the microporous solid
under study are particularly pronounced.