Cation-exchanged conductive Mn2DSBDC metal–organic frameworks: Synthesis, structure, and THz conductivity

Abstract

Conductive metal–organic frameworks (MOFs) are an emerging class of materials that rely upon crystallographically-defined charge-transport pathways that can be synthetically designed. Such conductive MOFs, including Mn-based MOFs, have not yet found applications in electrocatalysis at least partly due to restrictions in their tunability, as compositional or structural changes may interrupt the purposefully-designed charge-transport pathways. In this work, we provide an original strategy to exchange a portion of the Mn2+ cations in the conductive MOF Mn2DSBDC (where DSBDC = 2,5-dimercaptoterephthalate) for either Ni2+, Cu2+, or Co2+. The bulk and local structures were characterized using powder X-ray diffraction and element-specific X-ray absorption spectroscopy, respectively, to understand the structural effects of cation exchange, supporting that cation exchange does not alter the overall structure of the MOF. Importantly, using time-domain THz spectroscopy, it was discovered that the cation exchange does not alter the conductivity of the MOF. This finding opens the door to functionalization and tunability with respect to the cation composition in Mn2DSBDC, strongly suggesting applications in electrocatalysis.