Due to their important role in biological systems, it is urgent to develop a material that can rapidly and sensitively detect the concentration of Fe 3+ and Al 3+ ions. In this work, a brand-new Cd II -based metal−organic framework [Cd-(BTBD) 2 (AIC)] n (JXUST-18, BTBD = 4,7-bis(1H-1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole and H 2 AIC = 5-aminoisophthalic acid) with a 4-connected sql topology was designed and synthesized. The symmetrical Cd II centers are linked by AIC 2− ligands with μ 3 -η 1 :η 1 :η 1 :η 1 coordination mode to form a [Cd 2 (COO) 2 ] secondary building unit (SBU). The contiguous SBUs are further connected by BTBD ligands to form a twodimensional (2D) layer structure. JXUST-18 can remain stable in aqueous solutions with pH values of 3−12 or in boiling water. Luminescent experiments suggest that JXUST-18 displays more than eightfold fluorescence enhancement in the presence of Fe 3+ and Al 3+ ions, and the detection limits for Fe 3+ and Al 3+ ions are 0.196 and 0.184 μM, respectively. Furthermore, the change in luminescence color is uncomplicatedly distinguishable with the naked eye under ultraviolet light at 365 nm. In addition, a series of devices based on JXUST-18 including fluorescence test strips, lamp beads, and composite films were developed to detect metal ions via visual changes in luminescence color. Significantly, JXUST-18 is a rare MOF-based turn-on fluorescence sensor for the detection of Fe 3+ ions. The theoretical calculation suggests that the complexation of Fe 3+ /Al 3+ ions and the −NH 2 group contributes to fluorescence enhancement.

As the alternatives of expensive and increasingly shortage 3He for ultralow-temperaturerefrigeration, molecule-based magnetorefrigerant materials have attracted much attention in the past decades. Among them, Gd(III)-based metal-organic frameworks and coordination polymers...

A novel three-dimensional Eu3+-based metal-organic framework with the formula {[(CH3)2NH2][Eu(BTDI)]∙H2O∙DMF}n (JXUST-25) was prepared by solvothermal method based on Eu3+ and 5,5'-(benzothiadiazole-4,7-diyl)diisophthalic acid (H4BTDI) with benzothiadiazole (BTD) luminescent groups. Due to...

Metal−organic frameworks (MOFs) provide a broad platform for detecting small organic molecules due to their good stabilities and unique luminescent properties. Herein, a one-dimensional Cd II -based double chain metal−organic framework {[Cd(BBIP)(CDDB)(H 2 O)]•2H 2 O} n (JXUST-30) derived from 3,5-bis(1H-benzo[d]imidazol-1-yl)pyridine (BBIP) and 4,4′-(9H-carbazole-3,6-diyl)dibenzoic acid (H 2 CDDB) was successfully synthesized by solvothermal method. Interestingly, the Cd II −BBIP chain could pass through the large cavity formed by CDDB 2− to make parallel one-dimensional double chains interlocked, resulting in a structural transition from a one-dimensional chain to a twodimensional plane (1D → 2D) and the enhancement of structural stability. The intense blue light emission and the excellent stability in aqueous solutions with the wide range of pH values, organic solvents, and even boiling water of JXUST-30 provide a platform for detecting small organic molecules. The sensing experiments indicate that JXUST-30 can be used as a multifunctional fluorescence turn-on sensor for detecting acetylacetone (acac), aldehydes (glyoxal and salicylaldehyde (SA)) with fast response time (<15 s) and high sensitivity (detection limits of 0.068, 0.060, and 0.051 ppm, respectively). In addition, the successful preparation of sensing devices based on JXUST-30 provides the possibility for practical application in fluorescence detection of small organic molecules.