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.

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)·HO are carried out to assemble eight Ln(III) coordination polymers [Ln(2,5-TDC)(1,10-Phen)(HO)] [Ln = Pr (), Nd ()], {[Tb(2,5-TDC)(1,10-Phen)(HO)]·DMF} (), and [Ln(2,5-TDC)(1,10-Phen)]·HO (Ln = Tb (), Dy (), Ho (), Er (), and Yb ()); = 0 for CP , , , and and = 1 for CP with two different space groups and dimensions. The as-synthesized polymers - 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 are explored in detail and are found to be highly sensitive for the detection of -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 M). Other nitro compounds (viz., -nitrobenzaldehyde, -nitroaniline, picric acid, -dinitrobenzene, -nitrophenol, and -nitroaniline) are also screened for potential sensing by CP .