A tripodal Schiff base ligand, 2,4,6-Tris(4-carboxybenzimino)-1,3,5-triazine (MT) and its trinuclear Dy(III), Er(III), and Gd(III) complexes were synthesized. These were characterized using UV-visible, IR, 1H, and 13C NMR spectroscopies, elemental analysis, and molar conductivity measurements. The spectral studies indicate that the ligand is hexadentate and coordinates to the Ln(III) ions through the oxygen atoms of the carboxylic group. The trinuclear complexes were characterized as being bridged by carboxylate anions to the Dy(III), Er(III), and Gd(III) salen centers and displaying a coordination number of six. Biological studies revealed that MT is more active against the test micro-organisms relative to the trinuclear complexes. Acute toxicity studies revealed that MT is safe and has a wide range of effective doses (ED50). In vivo antimalarial studies indicate that MT could serve as an effective antimalarial agent since it has parasitemia inhibition of 84.02% at 50 mg/kg and 65.81% at 25 mg/kg, close to the value (87.22%) of the standard drug—Artesunate. Molecular docking simulation studies on the compounds against SARS-CoV-2 (6Y84) and E. coli DNA gyrase (5MMN) revealed effective binding interactions through multiple bonding modes. The binding energy calculated for Er(III)MT-6Y84 and Er(III)MT-5MMN complexes showed active molecules with the ability to inhibit SARS-CoV-2 and E. coli DNA gyrase.

Homoleptic Co(II), Cu(II) and Ni(II) complexes of a hydrazone derived from 3‐acetyl‐2‐hydroxy‐6‐methyl‐4H‐pyran‐4‐one (dehydroacetic acid) and 2‐furoic acid hydrazide, and their heteroleptic analogues with 2,2′‐bipyridine were synthesized. The complexes were characterized by spectroscopic methods (ESI‐MS, IR and NMR), elemental analysis, magnetic susceptibility and molar conductance measurements. The homoleptic complexes adopted octahedral geometry, while the heteroleptic analogous had four‐coordinate tetrahedral (Co and Cu complexes) and square‐planar (Ni complex) geometries. The homoleptic complexes were non‐electrolytes, while the heteroleptic complexes were 1:1 electrolytes in DMSO. Antimicrobial experiments indicated that [Cu(L)2] and [Cu(L)(bipy)](CH3COO) had the best antibacterial activities, with MIC of 31.2 and 61.5 μg/ml against Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212, respectively. Molecular docking determined that [Cu(L)(bipy)]⋅CH3COO had the highest binding energy and hydrogen bonding interactions with one of the active sites of amino acid residue (LEU73). Density functional theory (DFT) calculations of the complexes revealed that [Cu(L)(bipy)]⋅CH3COO possessed low energy gap, suggesting a higher activity and ability to donate electrons to electron‐accepting species of biological targets.

Chemical modification of montmorillonite though popular may be expensive, environmentally noxious and can result in secondary contamination. Therefore, the need for eco-friendly and efficient treatment techniques. The use of thermally enhanced rice husk momtmorillonite combo (TRMC) for aqueous crude oil pollution was evaluated. The physical characterization of the sorbate revealed a light crude oil. Scanning electron microscopy of TRMC and untreated montmorillonite (UM) showed efficient utilization of the pores for crude oil sequestration.Temperatures, pH, initial oil concentration, dosage of sorbent and time were found to be significant in the batch sorption investigation. The heterogeneous surface nature of TRMC was elucidated by the Freundlich and scatchard model analysis. Langmuir monolayer maximum sorption capacity was 5.8 and 9.7 g/g for UM and TRMC respectively and the later found to be higher than most reported sorbents. The pseudo first order model gave better fit than pseudo second order, Bangham and Elovich model in kinetics based on regression and chi-square analysis. Thermodynamics showed a spontaneous, feasible, endothermic and physical sorption process. Regeneration and reusability studies using n-hexane as eluent showed TRMC as suitable, environmental friendly sorbents for oil spill remediation.

N-(Benzothiazol-2-yl)-4-chlorobenzenesulphonamide (NBTCS) was synthesized by condensation reaction of 4-chlorobenzenesulphonyl chloride and 2-aminobenzothiazole in acetone under reflux. Neodymium(III) and thallium(III) complexes of the ligand were also synthesized. Both ligand and metal complexes were characterized using UV-Vis, IR, 1H- and 13C-NMR spectroscopies, elemental analysis and molar conductance measurement. IR studies revealed that the ligand is tridentate and coordinates to the metal ions through nitrogen and oxygen atoms of the sulphonamide group and nitrogen atom attached to benzothiazole ring. The neodymium(III) complex displays a coordination number of eight while thallium(III) complex displays a coordination number of six. The ligand and its complexes were screened in vitro for their antibacterial activities against Escherichia coli strains (E. coli 6 and E. coli 13), Proteus species, Staphylococcus aureus and Pseudomonas aeruginosa using the agar well diffusion technique. The synthesized compounds were found to be more active against the microorganisms screened relative to ciprofloxacin, gentamicin and co-trimoxazole.