Synthesis, crystal structure, antibacterial activity and theoretical studies on a novel mononuclear cobalt(II) complex based on 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand

Structural and Electronic Modulations of Imidazolium Covalent Organic Framework-Derived Electrocatalysts for Oxygen Redox Reactions in Rechargeable Zn-Air Batteries

Covalent organic frameworks (COFs) are promising candidates for the controllable design of electrocatalysts. However, bifunctional electrocatalytic activities for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remain challenging in COFs. In this study, imidazolium-rich COFs (IMCOFs) with well-defined active sites and characteristic three-dimensional assembly structures were readily prepared, and their electronic structures were tuned by Co incorporation to elicit bifunctional electrocatalytic activities for the ORR and OER. The Co nanoparticle-incorporated spherical IMCOF-derived electrocatalyst (CoNP-s-IMCOF) exhibited lower overpotentials for the ORR and OER compared with the atomic Co-incorporated planar IMCOF-derived electrocatalyst (Co-p-IMCOF). Computational simulations revealed that the imidazole carbon sites of CoNP-s-IMCOF rather than the triazine carbons were the active sites for the ORR and OER, and its p-band center downshifted via charge transfer, facilitating the chemisorption of oxygen intermediates during the reactions. A Zn-air battery with CoNP-s-IMCOF exhibited a small voltage gap of 1.3 V with excellent durability for 935 cycles. This approach for control over the three-dimensional assembly and electronic structures of IMCOFs can be extended to the development of diverse catalytic nanomaterials for applications of interest.

An experimental and theoretical exploration of supramolecular interactions and photoresponse properties of two Ni(ii) complexes

Two new nickel(ii) complexes, C₃₂H₂N₈NiClO₉ (1) and C₃₆H₂₈N₁₂NiOF₂₄P₄ (2) are reported. The noncovalent interactions witnessed in their crystal packing have been analysed using DFT calculations.

Synthesis and crystal structure of the simultaneous binding of Ni(ii) cation and chloride by the protonated 2,4,6 tris-(2-pyridyl)-1,3,5 triazine ligand: theoretical investigations of anion⋯π, π⋯π and hydrogen bonding interactions

A new octahedral Ni(ii) complex of a protonated 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand has been synthesized and X-ray analysis exhibited cooperative anion–π and H-bonding interactions.

Studies on physicochemical and antibacterial deeds of amino acid based L-Threoninum sodium bromide

Highly translucent nonlinear single crystals of L-Threoninum Sodium Bromide (LTSB) has been grown because of their rising need for everyday life and the XRD studies (PXRD and SXRD) solemnly affirmed the crystallinity and non-centrosymmetric space group of LTSB materials. The bonding nature and diverse functional groups in LTSB were demonstrated by FTIR analysis when they absorb infrared radiation. The optical behavior of LTSB crystals was explored through UV–Vis spectroscopy, which shows optical parameters depend on photon energy with band gap E_g = 5.7 eV which was suitable for optoelectronic devices. The electrical properties of LTSB crystals were measured by using dielectric measurement. The solid state parameters of LTSB crystal were calculated. An antibacterial activity developed by LTSB crystals against different pathogenic bacteria were examined using the Agar disk diffusion process. The antibacterial inhibitory activity of LTSB crystal revealed that it can be used to treat a variety of bacterial infections.

Synthesis, crystal structure and immobilization of a new cobalt(ii) complex with a 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand on modified magnetic nanoparticles as a catalyst for the oxidation of alkanes

A new Co(ii) complex with formula [Co(tptz)Cl₂]·2H₂O (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) has been synthesized and characterized, followed by being supported on modified magnetic nanoparticles as a catalyst for the oxidation of alkanes.

Oxidatively Locked [Co₂L₃]6+ Cylinders Derived from Bis(bidentate) 2-Pyridyl-1,2,3-triazole "Click" Ligands: Synthesis, Stability, and Antimicrobial Studies

A small family of [Co₂(Lpytrz)₃]6+ cylinders was synthesised from bis(bidentate) 2-pyridyl-1,2,3-triazole "click" ligands (Lpytrz) through an "assembly-followed-by-oxidation" method. The cylinders were characterised using ¹H, 13C, and DOSY NMR, IR, and UV-Vis spectroscopies, along with electrospray ionisation mass spectrometry (ESMS). Stability studies were conducted in dimethyl sulfoxide (DMSO) and D₂O. In contrast to similar, previously studied, [Fe₂(Lpytrz)₃]4+ helicates the more kinetically inert [Co₂(Lpytrz)₃]6+ systems proved stable (over a period of days) when exposed to DMSO and were even more stable in D₂O. The triply stranded [Co₂(Lpytrz)₃]6+ systems and the corresponding "free" ligands were tested for antimicrobial activity in vitro against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) microorganisms. Agar-based disk diffusion and Mueller-Hinton broth micro-dilution assays showed that the [Co₂(Lpytrz)₃]6+ cylinders were not active against either strain of bacteria. It is presumed that a high charge of the [Co₂(Lpytrz)₃]6+ cylinders is preventing them from crossing the bacterial cell membranes, rendering the compounds biologically inactive.