A series of color-tunable light-emitting open-framework lanthanide sulfates containing extra-large 36-membered ring channels

Abstract

A series of isostructural lanthanide sulfates LnSO₄-NTU1 (Ln = Eu (1), Tb (2), Sm (3), Dy (4), and Er (5)) containing extra-large 36-membered ring (36-MR) channels were prepared by employing “scale chemistry” theory with cluster building units. The 2-fold interpenetrated dia network was assembled with tetrahedral {Ln₁₀(SO4)₁₆} clusters. A single dia framework contains 36-MR channels with the pore size (22.0 × 16.8 Å) reaching the mesoscale. The discovery of LnSO₄-NTU1 sets a new record, pushing the existing maximum channel size of metal sulfates from 24-MR forward up to 36-MR. Notably, mix-Eu/TbSO₄-NTU1 exhibits color-tunable luminescence from red to green through adjusting the molar ratio of Eu : Tb in the frameworks.