A Boiling-Water-Stable, Tunable White-Emitting Metal-Organic Framework from Soft-Imprint Synthesis

A new avenue for making porous frameworks has been developed by borrowing an idea from molecularly imprinted polymers (MIPs). In lieu of the small molecules commonly used as templates in MIPs, soft metal components, such as CuI, are used to orient the molecular linker and to leverage the formation of the network. Specifically, a linear dicarboxylate linker with thioether side groups reacted simultaneously with Ln³⁺ ions and CuI, leading to a bimetallic net featuring strong, chemically hard Eu³⁺-carboxylate links, as well as soft, thioether-bound Cu₂I₂ clusters. The CuI block imparts water stability to the host; with the tunable luminescence from the lanthanide ions, this creates the first white-emitting MOF that is stable in boiling water. The Cu₂I₂ block also readily reacts with H₂S, and enables sensitive colorimetric detection while the host net remains intact. White light/white heat: A porous metal-organic framework, inspired by conceptually crosscutting the molecular imprint of polymers and the template of zeolites, emits white light in boiling water. The MOF incorporates an effective hard-and-soft divide, in which the Eu^III-carboxylate framework holds up the primary grid, whereas the imbedded soft CuI block, like a template, can be dislodged (e.g., by reacting with H₂S) from the surrounding sulfur donors while the host net remains intact.