Supramolecular Tuning of Spin Crossover Properties in Isostructural Cocrystal Solvates
Lee T. Birchall, Amber T. Raja, Lewis Jackson, Helena J. Shepherd
Abstract
High Resolution Image Download MS PowerPoint Slide In order to improve strategies for the design of spin-crossover materials, it is necessary to develop and understand structure–property relationships, and this is best achieved by obtaining isostructural materials. In this work we synthesized a series of four isostructural cocrystal solvates using the [Fe(3-bpp) 2 ][A] 2 complex and the 2,2-dipyridyl disulfide coformer in methanol and ethanol (A = BF 4 – or PF 6 – ). The spin-crossover properties of the materials were determined by variable temperature single-crystal X-ray diffraction. They show the same SCO behavior but with shifted spin-crossover temperatures, which has been related to the hydrogen bond basicity, p K BHX of the anions, and solvents present. This relationship between hydrogen bond basicity and the spin-crossover transition temperature offers a design strategy for the supramolecular tuning of spin-crossover properties in specific isostructural materials.