Tunable spin-crossover behavior of the Hofmann-like network {Fe(bpac)[Pt(CN)4]} through host-guest chemistry.

A study of the spin-crossover (SCO) behavior of the tridimensional porous coordination polymer {Fe(bpac)[Pt(CN)4]} (bpac=bis(4-pyridyl)acetylene) on adsorption of different mono- and polyhalobenzene guest molecules is presented. The resolution of the crystal structure of {Fe(bpac)[Pt(CN)4]}⋅G (G=1,2,4-trichlorobenzene) shows preferential guest sites establishing π⋅⋅⋅π stacking interactions with the host framework. These host-guest interactions may explain the relationship between the modification of the SCO behavior and both the chemical nature of the guest molecule (electronic factors) and the number of adsorbed molecules (steric factors).