Guest Effect on Nanopatterned Spin-Crossover Thin Films

Nanopatterned thin films of the metalorganic framework {Fe(bpac)[Pt(CN)4]} (bpac=bis(4-pyridyl)acetylene) are elaborated by the combination of a sequential assembly process and a lithographic method. Raman microspectroscopy is used to probe the temperature dependence of the spin state of the iron(II) ions in the films (4090 nm in thickness), and reveals an incomplete but cooperative spin transition comparable to that of the bulk material. Adsorption/desorption of pyridine guest molecules is found to have a substantial influence on the spin-crossover properties of the thin layers. This interplay between hostguest and spin-crossover properties in thin films and nanopatterns demonstrates the potential ability of using this kind of material as a microsensor.