Synthesis and characterization of a new piperazine containing macroacyclic ligand and its Cu(ii) and Co(ii) complexes: An investigation of the ligand's silver specific fluorescent properties

Theoretical and solid-state structures of three new macroacyclic Schiff base complexes and the investigation of their anticancer, antioxidant and antibacterial properties

Three symmetrical macroacyclic Schiff base complexes were prepared from a ligand derived from the condensation reaction of 1,4-bis(2-aminophenyl)piperazine and salicylaldehyde (L) with Cu(ii), Ni(ii) and Co(ii) perchlorates. The ligand and the Schiff base complexes were characterized by elemental analyses, UV-vis, FT-IR and mass spectrometry, with the structure of [CoL] being determined by a single crystal X-ray structural analysis. In this complex, the cobalt is in a distorted trigonal prismatic coordination environment, surrounded by the six donor atoms of the deprotonated hexadentate ligand. In order to compare the experimental and theoretical data and determine structure parameters in all complexes, Density Functional Theory (DFT) calculations at the B3lyp and BP86 levels with Def2-TZVP basis set have been carried out. NBO and QTAIM analyses have been used to describe the nature of M-O and M-N bonding in these complexes. The synthesized complexes were screened for their antioxidant activities using the DPPH free radical scavenging assay while their bactericidal activity was evaluated by the paper disc diffusion method against both Gram-negative and Gram-positive bacteria, revealing strong antioxidant activities and moderate effectiveness against all bacteria tested. The cytotoxicity of the metal complexes was also investigated against AGS (gastric) and A549 (lung) adenocarcinoma cells.

a Versatile Schiff Base Chemosensor for the Determination of Trace Co2+, Ni2+, Cu2+, and Zn2+ in the Water and Its Bioimaging Applications

In this work, a simple and versatile Schiff base chemosensor (L) was developed for the detection of four adjacent row 4 metal ions (Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺) through colorimetric or fluorescent analyses. L could recognize the target ions in solutions containing a wide range of other cations and anions. The recognition mechanisms were verified with a Job's plot, HR-MS assays, and ¹H NMR titration experiments. Then, L was employed to develop colorimetric test strips and TLC plates for Co²⁺. Meanwhile, L was capable of quantitatively measuring the amount of target ions in tap water and river water samples. Notably, L was used for imaging Zn²⁺ in HepG2 cells, zebrafish, and tumor-bearing mice, which demonstrated its potential biological applications. Therefore, L can probably serve as a versatile tool for the detection of the target metal ions in environmental and biological applications.