Pyridine hydrazyl thiazole metal complexes: Synthesis, crystal structure, antibacterial and antitumor activity

Efficient extraction of nickel from chloride system using a cleaner extractant: Taking the example of processing nickel-aluminum slag remaining from spent hydroprocessing catalysts

The efficient recovery of nickel from chloride systems has long presented a challenge in the field. While solvent extraction is a viable approach, conventional extractants have been associated with drawbacks such as a high requirement for chloride ions and substantial consumption of acids and alkalis. In response to these challenges, this investigation developed and synthesized a novel thiazole-based extractant, N, N-Bis(4-thiazolylmethyl)octylamine (NNBT), tailored for the selective extraction of nickel from chloride systems. Findings from the study indicate that the nitrogen atom situated on the benzylamine framework within NNBT can interact synergistically with the chelating thiazole ring, facilitating effective nickel extraction and notably reducing the need for chloride ions. Furthermore, the extractant can be regenerated using deionized water, thereby obviating the necessity for additional consumption of acids and alkalis. Following the validation of NNBT as an environmentally sustainable and efficient nickel extractant within the chloride ion system, it was successfully employed to selectively and effectively extract nickel from the nickel-aluminum slag of spent HDP catalyst. The extracted nickel and aluminum were subsequently processed into electroplated nickel chloride and polyaluminum chloride, respectively, meeting the national standards of China. These outcomes underscore the eco-friendliness and promise of NNBT for nickel extraction from chloride systems.

An expeditious on-water regioselective synthesis of novel arylidene-hydrazinyl-thiazoles as DNA targeting agents

A series of twenty novel (E)-arylidene-hydrazinyl-thiazole derivatives has been synthesized employing α-bromo-β-diketones, thiosemicarbazide, and aromatic/heteroaromatic aldehydes with a simple and facile one-pot multicomponent reaction passageway. This organic transformation proceeds efficiently in aqueous media and demonstrated a large functional group tolerance. The structures and stereochemistry of the regioisomeric product were rigorously characterized using heteronuclear 2D NMR experiments. The binding potential of the synthesized analogs with B-DNA dodecamer d(CGCGAATTCGCG)₂ was primarily screened using molecular modeling tools and further, mechanistic investigations (either groove or intercalation) were performed using various spectroscopic techniques such as UV-Visible, Fluorescence, and Circular dichroism. The absorption spectra showed a hyperchromic shift in the absorption maxima of ctDNA with successive addition of thiazole derivatives, implying groove binding mode of interactions, further supported by displacement assay and circular dichroism analysis. Furthermore, steady-state fluorescence analysis revealed the static mode of quenching and moderate bindings between the ligand and DNA biomolecule. The competitive studies showed that the derivatives having a pyridinyl (heteroaromatic) group in their structure, bind with the nucleic acid of calf-thymus (ctDNA) more effectively in the minor groove region as compared with the aromatic substitutions.

Antioxidant Activity Evaluation and Assessment of the Binding Affinity to HSA of a New Catechol Hydrazinyl-Thiazole Derivative

Polyphenols have attained pronounced attention due to their ability to provide numerous health benefits and prevent several chronic diseases. In this study, we designed, synthesized and analyzed a water-soluble molecule presenting a good antioxidant activity, namely catechol hydrazinyl-thiazole (CHT). This molecule contains 3′,4′-dihydroxyphenyl and 2-hydrazinyl-4-methyl-thiazole moieties linked through a hydrazone group with very good antioxidant activity in the in vitro evaluations performed. A preliminary validation of the CHT developing hypothesis was performed evaluating in silico the bond dissociation enthalpy (BDE) of the phenol O-H bonds, compared to our previous findings in the compounds previously reported by our group. In this paper, we report the binding mechanism of CHT to human serum albumin (HSA) using biophysical methods in combination with computational studies. ITC experiments reveal that the dominant forces in the binding mechanism are involved in the hydrogen bond or van der Waals interactions and that the binding was an enthalpy-driven process. NMR relaxation measurements were applied to study the CHT–protein interaction by changing the drug concentration in the solution. A molecular docking study added an additional insight to the experimental ITC and NMR analysis regarding the binding conformation of CHT to HSA.

5-N-Arylaminothiazoles with pyridyl groups and their first-row transition metal complexes: synthesis, photophysical properties, and Zn sensing

A series of 5-N-arylaminothiazoles were synthesized with facile diversity-oriented synthesis from readily available starting materials via the reaction of thioamide dianions and thioformamides. The introduction of various substituents at the 2-position of a thiazole ring (i.e., 2-pyridyl, 4-methylpyridyl, and phenyl groups) and on the nitrogen atom (i.e., p-tolyl and phenyl groups) significantly influenced the absorption and emission spectra of the isolated compounds. X-ray analysis confirmed that the substituents at the amino site were twisted from a thiazole ring, while the formation of its nickel complex showed dinuclear metal complexes bridged with chlorine atoms. Moreover, the formation of zinc-thiazole complexes showed enhanced emission properties in solution and noticeable emission in a solid state. In addition, thiazole-bridged dypyrromethene type ligands showed high selectivity toward Zn+2, which make them good candidates for zinc sensing.