Preparation, structure and antioxidant property of manganese(II) and zinc(II) complexes with bis(N-ethylbenzimidazol-2-ylmethyl)allylamine

Zn-coordination polymers for fluorescence sensing various contaminants in water

Luminescent coordination polymers (LCPs) have garnered significant attention from researchers as promising materials for detecting contaminants. In this paper, three new LCPs ([Zn(tib)(opda)]n⋅H2O (1), [Zn3(tib)2(mpda)3]n⋅5H2O (2), [Zn (tib)(ppda)]n⋅H2O (3)) with different structures (LCP 1-3: 1D, 2D, 1D) using phenylenediacetic acid isomers and 1,3,5-tris (1-imidazolyl) benzene (tib) are synthesized. The specific surface areas (BET) of LCP 1-3 are 4 m2/g, 19 m2/g, and 13 m2/g respectively. LCP 1-3 exhibit excellent fluorescence properties and can serve as fluorescent probe for the detection of inorganic contaminants and organic contaminants. Due to the large BET of LCP 2, the detection limits for trace analytes surpass those of LCP 1 and 3. The detection limits of LCP 2 for Fe3+, nitrobenzene (NB), chloramphenicol (CAP), and pyrimethanil (PTH) are 8.3 nM, 0.016 μM, 0.19 μM, and 0.032 μM, respectively, and the fluorescence quenching rates are 98.6 %, 98.8 %, 92.3 %, and 98.8 %, respectively. These values outperform most reported in the literature. The quantum yields of LCP 1-3 are 11.84 %, 25.22 %, 22.00 % respectively. Real sample testing of LCP 1-3 reveals favorable performance, where spiked recoveries of LCP 2 for the detection of pyrimethanil in grape skins ranged from 99.62 % to 119.3 % with a relative standard deviation (RSD) of 0.627 % to 4.56 % (n = 3). The fluorescence quenching mechanism was attributed to a combination of photoelectron transfer (PET), resonance energy transfer (RET), and competitive absorption (CA). This study advances the application of LCPs in luminescence sensing and contributes to the expansion of novel materials for detecting environmental pollutants.

Biomedical applications of selective metal complexes of indole, benzimidazole, benzothiazole and benzoxazole: A review (From 2015 to 2022)

Indole, benzoxazole benzothiazole and benzimidazole are excellent classes of organic heterocyclic compounds. These compounds show significant application in pharmacy, industries, dyes, medicine, polymers and food packages. These compounds also form metal complexes with copper, zinc, cadmium, nickel, cobalt, platinum, gold, palladium chromium, silver, iron, and other metals that have shown to be significant applications. Recently, researchers have attracted enormous attention toward heterocyclic compounds such as indole, benzimidazole, benzothiazole, benzoxazole, and their complexes due to their excellent medicinal applications such as anti-ulcerogenic, anti-cancer, antihypertensive, antifungal, anti-inflammatory, antitubercular, antiparasitic, anti-obesity, antimalarial, antiglycation, antiviral potency, antineuropathic, analgesic antioxidant, antihistaminic, and antibacterial potentials. In this article, we summarize the medicinal applications of these compounds as well as their metal complexes. We hope this article will help researchers in designing and synthesizing novel and potent compounds with significant applications in various fields.

A Ni(II) coordination polymer with dual electrochemical functions: synthesis, crystal structure, hydrogen evolution reaction and l-ascorbic acid sensing

A two-dimensional Ni(II) coordination polymer (NiCP) of the formula {[NiL(terephthalate)(H2O)2]·2H2O} n (L = bis(1-(pyridin-4-ylmethyl)-benzimidazol-2-ylmethyl)ether), has been obtained from a solvothermal reaction, and characterized by single-crystal X-ray diffraction, elemental analysis, and IR and UV/Vis spectra. The coordinated terephthalate anions and the L ligands connect the Ni(II) ions in two directions, resulting in the construction of a corrugated layered structure. The electrochemical properties of a NiCP-CPE composite electrode supported by this coordination polymer were studied. For the electrocatalytic hydrogen evolution reaction, the required overpotential of this electrode (NiCP-CPE) is −521 mV when the current density reaches 10 mA cm−2. Compared with the solid carbon paste electrode (sCPE, −976 mV), the smaller overpotential proves effective electrocatalysis of the coordination polymer of the hydrogen evolution reaction. The doped electrode also exhibits high-efficiency in the electrochemical sensing of l-ascorbic acid in water, showing a detection limit of 0.28 μM in a linear range of 0.4–4000 μM.

A 2-D Zn(II) coordination polymer based on 4,5-imidazoledicarboxylate and bis(benzimidazole) ligands: synthesis, crystal structure and fluorescence properties

In this work, a new type of zinc(II) coordination polymer {[Zn(HIDC)(BBM)0.5]·H2O} n (Zn-CP) was synthesized using 4,5-imidazoledicarboxylic acid (H3IDC) and 2,2-(1,4-butanediyl)bis-1,3-benzimidazole (BBM) under hydrothermal conditions. Its structure has been characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. The Zn(II) ion is linked by the HIDC2− ligand to form a zigzag chain by chelating and bridging, and then linked by BBM to form a layered network structure. Adjacent layers are further connected by hydrogen bond interaction to form a 3-D supramolecular framework. The solid-state fluorescence performance of Zn-CP shows that compared with free H3IDC ligand, its fluorescence intensity is significantly enhanced.