Environment-Controlled Post-Synthetic Modifications of Iron Formate Frameworks

2019-03-04T19:16:15Z (GMT) by Szymon Sobczak Andrzej Katrusiak
New hybrid iron-formate perovskites have been obtained in high-pressure reactions. Apart from the pressure range, also the liquid environment of the sample regulates the course of transformations. Formate α-DmaFe2+Fe3+For6, when compressed in oil and in isopropanol at 1.40 GPa, transforms to a new phase γ, different than that phase β obtained at low-temperature. In glycerol phase α can be compressed to 1.40 GPa, but then reacts to DmaFe2+For3, with all Fe(III) cations reduced, surrounded by amorphous iron formate devoid of Dma cations. Another mixed-valence framework Dma3[Fe2+3Fe3+For6]2·CO2, can be produced from phase α incubated in methanol and ethanol at 1.15 GPa. These pressure-induced environment-sensitive modifications have been rationalised by the volume effects involving the oxidation states of Fe(II) and Fe(III), their high- and low-spin states as well as the properties of pressure transmitting media. The topochemical redox reactions controlled by pressure and the liquid environment offer new highly efficient, safe and environment-friendly reactions leading to new advanced materials and their post-synthesise modifications.