The missing MIL-101(Mn): geometrically guided synthesis and topologically correlated valence states

Abstract

Mixed-valence manganese complexes are of special interest in biocatalysis and magnetism research. Nevertheless, when including manganese clusters into metal–organic frameworks (MOFs), several issues such as valence control, phase selectivity, etc. were usually encountered, hence limiting the discovery of Mn MOFs. The long-sought MIL-101(Mn), a missing piece of the famous MIL-101 (Al, Sc, Ti, V, Cr, Fe) family, has finally been synthesized through a unique, controllable geometrically guided approach, different from the well-developed kinetically modulating approach. It is the first time that the single-crystal structure of a MIL-101 material has been determined by X-ray diffraction. Surprisingly, it is revealed that MIL-101(Mn) exhibits an emergent phenomenon of topologically correlated mixed-valence states, which are characterized by XPS and magnetic measurements. Moreover, the metastable Mn(III) species therein show enzymatic catalytic activity under mild conditions.