Mechanochemical and Conventional Synthesis of Zn(II)/Cd(II) Luminescent Coordination Polymers: Dual Sensing Probe for Selective Detection of Chromate Anions and TNP in Aqueous Phase

Abstract

Isostructural Zn(II)/Cd(II) mixed ligand coordination polymers (CPs) {[M(IPA)(L)]} (CP1 and CP2) built from isophthalic acid (HIPA) and 3-pyridylcarboxaldehyde nicotinoylhydrazone (L) were prepared using versatile synthetic routes: viz., diffusion of precursor solutions, conventional reflux methods, and green mechanochemical (grinding) reactions. Both robust CPs synthesized by different routes were characterized by various analytical methods, and their thermal and chemical stability as well as the phase purity was established. Crystallographic studies revealed that CP1 and CP2 are isostructural frameworks and feature a double-lined two-dimensional network composed of Zn/Cd nodes connected through IPA and pillared by the Schiff base ligand L with a double-walled edge. The photoluminescent (PL) properties of CP1 and CP2 have been exploited as dual detection fluorosensors for hexavalent chromate anions (CrO/CrO) and 2,4,6-trinitrophenol (TNP) because it was observed that the emission intensity of aqueous suspensions of CPs selectively quenches by chromate anions or TNP among large pools of different anions or nitro compounds, respectively. Competitive experiments in the presence of interfering anions/other nitro compounds also revealed no major effect in the quenching efficiency, suggesting the selective detection of hexavalent chromate anions as well as TNP by the LCPs. The limits of detection by CP1 for CrO/CrO and TNP are 4 ppm/4 ppm and 28 ppb, respectively, whereas the limits of detection by CP2 for the same analytes are 1 ppm/1 ppm and 14 ppb, respectively. A probable mechanism for the quenching phenomena is also discussed.

Cobalt(II) and silver(I) coordination polymers containing flexible bis (benzimidazol‐1‐yl)hexane ligands: synthesis, crystal structures, sensing and photocatalytic properties

“…On the basis of the experimental data, linear correlation coefficient (R 2 = 0.9843, K sv = 2.6783 × 10 4 M −1 ) of 2 at the concentrations of 0–2.5 × 10 −4 M (Figure c), and the detection limit of 0.29 μM. Thus, 2 can be used as a highly sensitive luminescent probe for the quantitative detection of Cr 2 O 7 2− ions …”

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

“…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.…”

Sensing and photocatalytic properties of nanosized Cu(I)CN organotin supramolecular coordination polymer based on pyrazine

“…Generally, there are two main reasons for sensing phenomena: photoinduced electron transfer or resonance energy transfer, or both . The quenching mechanism may be due to photoinduced electron transfer between the excited SCP 1 and the guest solvent molecules.…”

“…The quenching mechanism may be due to photoinduced electron transfer between the excited SCP 1 and the guest solvent molecules. The luminescence quenching caused by acetone molecules may be explained in terms of the photoinduced electron transfer theory . The carbonyl group in acetone can form hydrogen‐bond interactions with the fused hexagonal rings of SCP 1 and, during excitation, electron transfer from SCP 1 to acetone leads to luminescence quenching.…”

“…The carbonyl group in acetone can form hydrogen‐bond interactions with the fused hexagonal rings of SCP 1 and, during excitation, electron transfer from SCP 1 to acetone leads to luminescence quenching. On the other hand, the luminescence quenching may be due to physical interaction between the Pyz ligand used to construct SCP 1 and acetone where the energy absorbed by the ligand is transferred to acetone molecules, resulting in the luminescence quenching of SCP 1 according to resonance energy transfer mechanism …”