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A combination of N,N',N"-tris(3-pyridyl)-1,3,5-benzenetricarboxamide (L1) and p-chlorobenzoic acid (HL2) with Zn(NO3)2·6H2O resulted in the formation of a dinuclear metallacycle [ZnL1(L2)2(DMF)2]2 (1(DMF)4). In 1(DMF)4, the Zn(II) centre adopts a square pyramidal geometry, while one of the pyridyl N out of the three pyridyl groups in L1 remained uncoordinated. Solvated DMF molecules are present in 1(DMF)4. The structural and chemical nature of 1(DMF)4 is effective for it to act as a potential fluorescent probe for the detection of nitroaromatic compounds. It is observed that the probe, 1(DMF)4, could selectively detect picric acid (PA) among various aromatic compounds in solution (DMSO), while the solid state (contact mode) detection showed a positive sensing response for the nitrophenols (PA: 87% quenching efficiency, 2,4-dinitrophenol (2,4-DNP): 57% quenching efficiency and 4-nitrophenol (4-NP): 40% quenching efficiency). The limit of detection (LOD) of PA by the probe in DMSO was found to be 6.8 × 10-11 M while the LOD in contact mode detection was estimated to be 0.49 ng cm-2. The mechanism of selective detection of PA by 1(DMF)4 in DMSO was analyzed through photophysical studies, 1H-NMR experiments and also by density functional theory (DFT) calculations. The effective overlap of the absorption spectrum of 1(DMF)4 and emission spectrum of PA in DMSO suggests that the Förster resonance energy transfer (FRET) is responsible for quenching phenomena in DMSO. The DFT calculations and molecular docking studies showed the adduct formation due to the favorable interactions between 1(DMF)4 and PA in DMSO, while negligible interactions were observed between 1(DMF)4 with other aromatic compounds. The experimental and DFT studies showed that the efficient sensing ability of PA by 1(DMF)4 in the solid-state was due to photoelectron transfer (PET) and FRET phenomena described herein. [ABSTRACT FROM AUTHOR]

This work presents synthesis and characterization of two cobalt‐based coordination polymers (CPs) prepared by using two positionally related pyridine‐2,6‐dicarboxamide fragment‐based ligands containing appended arylcarboxylic acid groups. While arylcarboxylate groups of ligands coordinate to the Co(II) ions to produce 2D CPs; the amidic N−H groups remain free and generate large cavities lined with hydrogen bonds. Such hydrogen bonding cavities based CPs were found to reversibly adsorb molecular iodine. The Lewis acidic Co(II) ions and metal‐coordinated labile solvent molecules in CPs promoted noteworthy heterogeneous catalysis for Friedel crafts reactions as well as multicomponent condensation reactions. [ABSTRACT FROM AUTHOR]

We present two ZnII‐ and CdII‐based coordination polymers (CPs), L‐Zn and L‐Cd, offering H‐bonding‐based cavities of varying dimensions. Both CPs were used for the highly selective detection of S2O72− and Fe3+ ions where H‐bonding based cavities played an important role. Fluorescence quenching, competitive binding studies and binding parameters substantiated significant recognition of S2O72− and Fe3+ ions by both CPs. [ABSTRACT FROM AUTHOR]

We present two Zn II - and Cd II -based coordination polymers (CPs), L-Zn and L-Cd, offering H-bonding-based cavities of varying dimensions. Both CPs were used for the highly selective detection of S 2 O 7 2- and Fe 3+ ions where H-bonding based cavities played an important role. Fluorescence quenching, competitive binding studies and binding parameters substantiated significant recognition of S 2 O 7 2- and Fe 3+ ions by both CPs., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)