| Abstract
| - The porous coordination framework material, Fe(NCS)2(bped)2·3EtOH, SCOF-3(Et) (where bpedis dl-1,2-bis(4‘-pyridyl)-1,2-ethanediol), displays a spin-crossover (SCO) transition that has been stimulatedboth thermally and by light irradiation. The one-step thermal SCO (70−180 K) is sensitive to the presenceof molecular guests, with a more gradual transition (70−225 K) apparent following the desorption of ethanolmolecules that hydrogen bond to the spin centers. Additional intraframework hydrogen-bonding interactionsstabilize the vacant one-dimensional pore structure of the apohost, SCOF-3, despite a dramatic single-crystal to single-crystal (SC−SC) structural change upon removal of the guests. Comprehensive structuralanalyses throughout this transformation, from primitive orthorhombic (Pccn) to body-centered tetragonal(I4/mcm), reveal a flexing of the framework and a dilation of the channels, with an accompanying subtledistortion of the iron(II) coordination geometry. Photomagnetic measurements of the light-induced excitedspin state trapping (LIESST) effect have been used to assess the degree of cooperativity in this system.
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