A Bifunctional Zn(II) Metal–Organic Framework for C ₃ H ₆ /C ₂ H ₄ Separation and Fluorescent High-Temperature Sensing

The development of multifunctional metal–organic frameworks (MOFs) that combine efficient gas separation with reliable sensing remains a challenging but highly desirable goal. Herein, we report a Zn-based MOF, {[Zn 3 (NTB) 2 (bib)]·(DMA) 2 ·(H 2 O) 4 } n (denoted as DZU-211-Zn), constructed from 4,4',4''-nitrilotribenzoic acid (H 3 NTB) and 1,4-bis(imidazol-1-yl)-butane (bib). DZU-211-Zn exhibits excellent separation performance for propylene/ethylene (C 3 H 6 /C 2 H 4 ) mixtures, with a C 3 H 6 uptake of 3.0 mmol g –1 and a C 2 H 4 uptake of 2.3 mmol g –1 at 298 K and 1 bar, and a C 3 H 6 /C 2 H 4 selectivity above 10. Dynamic breakthrough experiments confirm efficient and repeatable separation over multiple cycles. Meanwhile, the material displays intense blue fluorescence (quantum yield, 38.4%) with a highly linear, reversible, temperature-dependent emission quenching from room temperature up to 473 K, affording a relative sensitivity ranging from 0.35% K –1 at 298 K to 0.88% K –1 at 473 K. To the best of our knowledge, DZU-211-Zn represents one of the rare examples of a MOF that integrates light-hydrocarbon separation and high-temperature fluorescence thermometry in a single platform. This work paves the way for the construction of multifunctional MOF materials.