Vanadium 8-hydroxyquinoline derivatives in medicine: current state and future outlook

Vanadium complexes featuring 8-hydroxyquinoline ligands and their derivatives have emerged as a promising class of compounds with potential therapeutic applications, particularly as antimicrobial and anticancer agents. This comprehensive review offers a timely and insightful analysis of the current landscape of vanadium complexes with HQ ligand or its derivatives, whether alone or in combination with organic coligands. This review covers synthetic strategies, and mechanisms that underlie their antibacterial and anticancer activities. A significant focus of this review is the thorough evaluation of the antibacterial and anticancer properties of these complexes, providing an invaluable resource for researchers in the interdisciplinary fields of inorganic chemistry, medicinal chemistry, and drug discovery. By compiling and synthesizing the existing knowledge on vanadium-8-hydroxyquinoline (VO-8HQ) complexes, this review addresses a critical gap in the literature. Ongoing research, including rigorous preclinical and clinical evaluations, is essential for fully exploring the therapeutic potential of this promising class of metallodrugs.

Bis(2,6-pyrazolyl)pyridines as a New Scaffold for Coordination Polymers

Two coordination polymers, Fe(L^OBF₃)(CH₃COO)(CH₃CN)₂]_n•nCH₃CN and [Fe(L^O-)₂AgNO₃BF₄•CH₃OH]_n•1.75nCH₃OH•nH₂O (L^O- = 3,3'-(4-(4-cyanophenyl)pyridine-2,6-diyl)bis(1-(2,6-dichlorophenyl)-1H-pyrazol-5-olate)), were obtained via a PCET-assisted process that uses the hydroxy-pyrazolyl moiety of the ligand and the iron(II) ion as sources of proton and electron, respectively. Our attempts to produce heterometallic compounds under mild conditions of reactant diffusion resulted in the first coordination polymer of 2,6-bis(pyrazol-3-yl)pyridines to retain the core N₃(L)MN₃(L). Under harsh solvothermal conditions, a hydrogen atom transfer to the tetrafluoroborate anion caused the transformation of the hydroxyl groups into OBF₃ in the third coordination polymer of 2,6-bis(pyrazol-3-yl)pyridines. This PCET-assisted approach may be applicable to produce coordination polymers and metal-organic frameworks with the SCO-active core N₃(L)MN₃(L) formed by pyrazolone- and other hydroxy-pyridine-based ligands.

Characterization and antidiabetic activity of salicylhydrazone Schiff base vanadium(IV) and (V) complexes

Twenty-four oxidovanadium(IV,V) complexes with tridentate Schiff base ligands based on 5-nitrosalicylaldehyde, 5-methoxysalicylaldehyde, or 5-sulfosalicylaldehyde and respective hydrazide were isolated, and characterized using physicochemical and spectroscopic methods. Three of them were structurally characterized by single-crystal X-ray structure determination. The biological activity studies included inhibition of human tyrosine phosphatases, studies on myocyte C2C12, adipocyte 3T3-L1, and human hepatocyte HepG2 cell lines, glucose uptake in myocytes and adipocytes, and cytotoxicity tests. The complexes that were unstable in solutions showed biological activity typical of other V(IV) complexes, while the stable one showed much higher, ligand-dependent, activity.