Guest tunable structure and spin crossover properties in a nanoporous coordination framework material.

The electronic switching properties of the nanoporous spin crossover framework [Fe(NCS)(2)(bpbd)(2)] x x(guest), SCOF-2, can be rationally manipulated via sorption of a range of molecular guests (acetone, ethanol, methanol, propanol, 1-acetonitrile) into the 1-D channels of this material. Pronounced changes to the spin crossover properties are related directly to the steric and electronic influence of the individual guests: the degree of lattice cooperativity, as reflected in the abruptness of the transition and presence of hysteresis, is strongly influenced by the presence of cooperative host-guest interactions, and the temperature of the transition varies with guest polarity through a proposed electrostatic interaction.