Photo- and Electronically Switchable Spin-Crossover Iron(II) Metal-Organic Frameworks Based on a Tetrathiafulvalene Ligand

Angew Chem Int Ed Engl. 2017 May 8;56(20):5465-5470. doi: 10.1002/anie.201611824. Epub 2017 Apr 12.

Abstract

A major challenge is the development of multifunctional metal-organic frameworks (MOFs), wherein magnetic and electronic functionality can be controlled simultaneously. Herein, we rationally construct two 3D MOFs by introducing the redox active ligand tetra(4-pyridyl)tetrathiafulvalene (TTF(py)4 ) and spin-crossover FeII centers. The materials exhibit redox activity, in addition to thermally and photo-induced spin crossover (SCO). A crystal-to-crystal transformation induced by I2 doping has also been observed and the resulting intercalated structure determined. The conductivity could be significantly enhanced (up to 3 orders of magnitude) by modulating the electronic state of the framework via oxidative doping; SCO behavior was also modified and the photo-magnetic behavior was switched off. This work provides a new strategy to tune the spin state and conductivity of framework materials through guest-induced redox-state switching.

Keywords: iodine; iron; metal-organic frameworks; spin crossover; tetrathiafulvalenes.

Publication types

  • Research Support, Non-U.S. Gov't