Multifunctional Mn(II) Metal-Organic framework for photocatalytic aerobic oxidation and C[sbnd]H direct trifluoromethylation

Abstract

The design and synthesis of multifunctional metal–organic frameworks (MOFs) has been widely attentions and certain challenges. In this work, we successfully synthesized and designed a 3D Mn-MOF ([Mn4(L)4(DMF)3]n (Mn-MOF), L = 4,4′-(anthracene-9,10-diyl)dibenzoic acid). Structural analysis suggests that the Mn(II) ions in each one-dimensional (1D) arrangement are evenly distributed on both sides of the central pseudoatomic column, and each two Mn(II) ion centers are coordinated with five or four oxygen atoms from five or four L ligands to form a 1D chain structure. The 1D chains are linked one to another via ligands to form a 3D framework that generates 3D channels of rhombic aperture. In this work, the anthracene group with conjugated structure was successfully inserted into the highly porous stable Mn-MOF, which showed obvious photoactivity. In photocatalytic studies, Mn-MOF not only shows high catalytic activity on the aerobic oxidation of benzyl alcohol via the generation of O2− under 420 nm light irradiation but also exhibits well efficiency in the trifluoromethylation of different arenes by the formation of the trifluoromethyl radical (CF3) as an intermediate. Mn-MOF has high recoverability and applicability to various substrates, which makes it a potential photocatalyst.