Redox-switchable breathing behavior in tetrathiafulvalene-based metal-organic frameworks.

Su, Jian; Yuan, Shuai; Wang, Hai-Ying; Huang, Lan; Ge, Jing-Yuan; Joseph, Elizabeth; Qin, Junsheng; Cagin, Tahir et al. · Nat Commun · 2017

basic_science · Level V

Where this comes from

Abstract

Metal-organic frameworks (MOFs) that respond to external stimuli such as guest molecules, temperature, or redox conditions are highly desirable. Herein, we coupled redox-switchable properties with breathing behavior induced by guest molecules in a single framework. Guided by topology, two flexible isomeric MOFs, compounds 1 and 2, with a formula of In(Me<sub>2</sub>NH<sub>2</sub>)(TTFTB), were constructed via a combination of [In(COO)<sub>4</sub>]<sup>-</sup> metal nodes and tetratopic tetrathiafulvalene-based linkers (TTFTB). The two compounds show different breathing behaviors upon the introduction of N<sub>2</sub>. Single-crystal X-ray diffraction, accompanied by molecular simulations, reveals that the breathing mechanism of 1 involves the bending of metal-ligand bonds and the sliding of interpenetrated frameworks, while 2 undergoes simple distortion of linkers. Reversible oxidation and reduction of TTF moieties changes the linker flexibility, which in turn switches the breathing behavior of 2. The redox-switchable breathing behavior can potentially be applied to the design of stimuli-responsive MOFs.