Magnetism and luminescence of a MOF with linear Mn3 nodes derived from an emissive terthiophene-based imidazole linker

Abstract

A new terthiophene-based imidazole luminophore 5,5’-(1H-thieno[3,4-d]imidazole-4,6-diyl)bis(thiophene-2-carboxylic acid) (TIBTCH2, 5) was synthesized in one step from previously re-ported 4,6-di(thiophen-2-yl)-1H-thieno[3,4-d]imidazole (DTTI, 4), and their photophysical properties were studied and compared accordingly. Under solvothermal conditions, reacting 5 with Mn(OAc)2 yielded a new three-dimensional metal-organic framework (MOF, 6) which was structurally de-fined by single-crystal X-ray diffraction. In 6, all Mn(II) ions octahedrally bind to carboxylate-O atoms to form a linear Mn3 secondary building unit (SBU) that contains three distinct coordination modes. Importantly, 6 exhibits dual functional properties of ligand-based emission and metal-based magnetic behaviors.