Syntheses and Structural Analyses of New 3D Isostructural Zn(II) and Cd(II) Luminescent MOFs and their Application Towards Detection of Nitroaromatics in Aqueous Media

Abstract

Two new isostructural luminescent metal‐organic frameworks (LMOFs); {[M(BDC)(L)].xG}n, comprising Zn2+ (1) or Cd2+ (2) nodes, 4‐pyridyl carboxaldehyde isonicotinoylhydrazone (L), Benzene‐1,4‐dicarboxylic acid (H2BDC) and lattice guests (G) have been synthesized by diffusion, conventional and mechanochemical routes and thoroughly characterized. Single crystal structural analysis revealed doubly interpenetrating double pillared primitive cubic unit (pcu) structures with significant stability at ambient conditions and in water for 1 and 2. Moreover, both structures showed good luminescent properties which are exploited for detection of nitro analytes. Fluorescence quenching experiments performed for a large pool of aromatic and aliphatic nitroanalytes showed that 1 and 2 selectively detect Trinitrophenol (TNP) in aqueous phase. The linear fitting of the SV plots for TNP offered quenching constants of 1.16 × 104 M−1 and 1.35 × 104 M−1 for 1 and 2 respectively indicating the high sensitivity of the sensing process. Remarkable sensitivity of synthesized materials towards aqueous phase TNP detection were further endorsed by the detection limits of 82 ppb (0.36 μM) and 33 ppb (0.15 μM) in case of 1 and 2 respectively. Thus, these new LMOFs owing to their high water stability and remarkable functional features are potential candidates which can be developed into selective and sensitive TNP detection devices.

Zn(ii)/Cd(ii) based mixed ligand coordination polymers as fluorosensors for aqueous phase detection of hazardous pollutants

“…In addition to the PET and RET mechanism, quenching behaviour is also supplemented by H-bonding interaction between the amide group of L 2 and the hydroxyl group of TNP via co-crystal formation. 69 In another example, two dimensional Cd(II) MOFs [Cd(5-BrIP) (TIB)] n (8) synthesized by our group using tripodal N-donor 1,3,5-tris(imidazol-1-ylmethyl)benzene (TIB) and 5-bromoisophthalate (5-BrIP) showed excellent photoluminescence properties in the solid state and in water. Fluorescence properties of the chemically stable ( 8) are exploited for the selective detection of TNP from a large pool of other nitroaromatics.…”

Efficient Solvent‐Free Carbon Dioxide Fixation Reactions with Epoxides Under Mild Conditions by Mixed‐Ligand Zinc(II) Metal–Organic Frameworks

“…A detailed structural analysis and physical characterization by using various analytical methods was performed on ZnMOF‐1 and ZnMOF‐2 synthesized by adaptable routes to elucidate the bulk phase purity. Crystallographic studies revealed that both ZnMOF‐1 and ZnMOF‐2 crystallized in a triclinic system in the P space group and feature 3 D and 2 D frameworks, respectively, which were composed of Zn II metal nodes connected through dicarboxylate ligands and pillared by the Schiff base ligand (Figure a and c) . The 3 D framework in ZnMOF‐1 is constituted by 2 D [Zn 2 (bdc) 2 ] n secondary building units (SBUs) with a versatile coordination mode of the carboxylate group to generate sql (square lattice) nets, which are doubly pillared by L1 in the corresponding twofold interpenetrated pcu (primitive cubic lattice) type 3 D networks.…”

“…In this contribution, mixed‐ligand 3 D/2 D ZnMOFs {[Zn(bdc)( L1 )]⋅ x G} n ( ZnMOF‐1 ) and {[Zn(ipa)( L2 )]} n ( ZnMOF‐2 ) (in which H 2 BDC=benzene‐1,4‐dicarboxylic acid, L1 =4‐pyridyl carboxaldehyde isonicotinoylhydrazone, H 2 IPA=isophthalic acid, L2 =3‐pyridyl carboxaldehyde nicotinoyl hydrazone, and G=lattice guests) were synthesized by versatile synthetic routes, namely, a conventional reflux method and a green mechanochemical (grinding) reaction reported previously by us, and exploited for their potential as a catalyst in CO 2 fixation. The phase purity of bulk compounds synthesized by versatile routes was established by different analytical methods, and crystal structure analysis revealed 3 D and 2 D motifs in ZnMOF‐1 and ZnMOF‐2 , respectively.…”

A Novel Zinc Luminescent Coordination Polymer Based on a Tetracarboxylate Acid Ligand for the Detection of Nitrobenzene

“…In past several decades, coordination polymers (CPs), as a class of multifunction materials assembled from organic multi‐carboxylic acid ligands and metal ions or clusters, have been obtained enormous attention because of their fascinating structural and interesting chemical properties, such as magnetism, gas storage, catalysis, drug delivery, chemical sensing, and other fields . Particularly, luminescent coordination polymers (LCPs) have been considered as excellent candidates to obtain high sensitive detectors for chemical sensing of metal ions, small organic molecules, explosives, and anions …”