Multifunctional Fluorescence Turn-On Sensor for Acetylacetone, Glyoxal, and Salicylaldehyde Based on a Highly Stable 1D → 2D Interlocked Cd(II) Metal–Organic Framework

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 CdII-based double chain metal–organic framework {[Cd(BBIP)(CDDB)(H2O)]·2H2O}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 (H2CDDB) was successfully synthesized by solvothermal method. Interestingly, the CdII–BBIP chain could pass through the large cavity formed by CDDB2– to make parallel one-dimensional double chains interlocked, resulting in a structural transition from a one-dimensional chain to a two-dimensional 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.