Dual-Ligand Strategy Employing Rigid 2,5-Thiophenedicarboxylate and 1,10-Phenanthroline as Coligands for Solvothermal Synthesis of Eight Lanthanide(III) Coordination Polymers: Structural Diversity, DFT Study, and Exploration of the Luminescent Tb(III) Coordination Polymer as an Efficient Chemical Sensor for Nitroaromatic Compounds

Abstract

Lanthanide coordination polymers (Ln-CPs) are potential chemosensors when fabricated to depict a detectable change in optical properties on interaction with target analytes. This work investigates the interaction of nitroaromatic compounds with Ln-CPs leading to induced changes in fluorescence emission intensity, a crucial strategy to develop a selective and sensitive system for the sensing of nitroaromatics. Approaching toward this objective, solvothermal reactions of 2,5-thiophenedicarboxylic ( 2,5-TDC) acid, 1,10-phenanthroline (1,10-Phen), and Ln(NO 3 ) 3 •xH 2 O are carried out to assemble eight Ln(III) coordination polymers [Ln 2 (2,5-TDC) 3 (1,10-Phen) 2 (H 2 O) 2 ] [Ln = Pr (1), Nd (2)], {[Tb(2,5-TDC) 1.5 (1,10-Phen)(H 2 O)]• DMF} (3), and [Ln(2,5-TDC) 1.5 (1,10-Phen)]•xH 2 O (Ln = Tb (4), Dy ( 5), Ho (6), Er (7), and Yb (8)); x = 0 for CP 4, 5, 6, and 8 and x = 1 for CP 7 with two different space groups and dimensions. The as-synthesized polymers 1−8 are characterized by powder X-ray crystallography, infrared spectroscopy, and thermogravimetric analysis. The structure-corroborated density functional theory (DFT) studies are done on the selected CPs to investigate the interactions between different structural motifs of the assembled CPs. The luminescence properties of CP 4 are explored in detail and are found to be highly sensitive for the detection of p-nitrotoluene as indicated by the most intensive fluorescence quenching with the lowest limit of detection (0.88 ppm) and high quenching constant (4.3 × 10 4 M −1 ). Other nitro compounds (viz., o-nitrobenzaldehyde, m-nitroaniline, picric acid, mdinitrobenzene, p-nitrophenol, and p-nitroaniline) are also screened for potential sensing by CP 4.

Selective and Rapid Detection of 4-Nitrophenol in River and Treated Industrial Wastewater by a Luminescent Lanthanide Metal–Organic Framework Sensor

“…Metal–organic frameworks (MOFs) are crystalline porous materials composed of metal ions/clusters and organic linkers, which have been extensively applied in the detection of cations, − anions, biomarkers, − and small organic molecules. , MOFs have been explored for 4-NP detection via their fluorescence sensing mechanisms and have shown excellent detection capabilities. − For example, Wang et al studied the trace detection of a range of nitrophenol compounds in DMF solution with Tb-MOF, reporting a sensitivity of 2.25 × 10 4 M –1 and a limit of detection (LOD) of 1.12 × 10 –6 M for 4-NP . In addition, Guo et al reported that Eu-MOF emitted bright red luminescence and could function as a luminescent sensor for 4-NP in aqueous media with high sensitivity, selectivity, and a low detection limit .…”

A highly stable and efficient benzothiadiazole-based fluorescence sensor for salicylaldehyde in aqueous solution

“…As a class of inorganic-organic hybrid materials, coordination polymers (CPs) are widely used in chemical sensing, [12][13][14][15] gas adsorption 16,17 and separation, 18 catalysis, 19 and drug delivery. [20][21][22] Due to their good light absorption and electron transport properties, they can be used as ideal candidates for fluorescence sensing.…”

Designing scintillating coordination polymers using a dual-ligand synthetic approach

“…42,43 Aside from these structural implications, the resulting material functionality tends to diversify, given that the properties of each ligand become integrated with those of the metal center. 44–47…”