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The crystal and molecular structures of a new dinuclear oxidovanadium(IV) complex with the N -(phosphonomethyl)iminodiacetate (pmida) ligand and the 4-amino-2-methylquinolinium ([amqH] + ) cation of the molecular formula [amqH] 4 [V 2 O 2 (pmida) 2 ]6H 2 O have been determined. The phosphonate groups in the two pmida 4− ligands form two bridges between adjacent V 4+ atoms, resulting in the formation of a [V 2 O 2 (pmida) 2 ] 4− dimer with a V 2 O 4 P 2 eight-membered ring. This is the first example of a quinoline derivative complex containing the [V 2 O 2 (pmida) 2 ] 4− ion. The susceptibility curve for the complex exhibits a maximum at approximately 10 K, indicating the presence of antiferromagnetic interactions transmitted in the crystal lattice. Furthermore, the biological properties of the complex in the concentration range 1–100 μM were investigated in relation to its cytoprotective activity against oxidative damage generated exogenously using hydrogen peroxide in the hippocampal neuronal HT22 cell line (MTT tests). The obtained results were subsequently referred to the [amqH][VO(nta)(H 2 O)]H 2 O analogue as well as trolox and ascorbic acid, used as known antioxidants. It has been established that the title compound effectively protects HT22 from oxidative damage and is a potentially good candidate for further evaluation of the mechanism of its action. [ABSTRACT FROM AUTHOR]

The crystal structure of a nitrilotriacetate (nta) oxidovanadium(IV) salt with 4-methylpyridinium cation, [4-Me(Py)H]+, of [4-Me(Py)H][VO(nta)(H2O)] stoichiometry was determined. The complex comprises a discrete mononuclear [VO(nta)(H2O)]-coordination entity that can be rarely found among other known compounds containing nitrilotriacetate oxidovanadium(IV) moieties. The complex was characterized by spectroscopic (IR and EPR) methods, magnetic measurements, and thermogravimetry (TG-FTIR). The stability of the title compound in aqueous solutions was investigated by using the potentiometric titration method. Furthermore, spectrophotometric (UV/Vis) studies have revealed that the compound is capable to scavenge the superoxide free radicals (O2•-) as well as stable organic radicals i.e. 2,2'-azinobis(3-ethylbenzothiazoline-6 sulfonic acid) cation radical (ABTS+•) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•). Finally, biological properties of the complex studied were investigated in relation to its cytoprotective activity against the oxidative damage generated exogenously by using hydrogen peroxide in the HT22 hippocampal neuronal cell line (the MTT assay). Additionally, the biological action of the compound towards two human osteosarcoma HOS and MG-63 cell lines (the MTT and BrdU tests) as well as the untransformed human osteoblast hFOB 1.19 cell line was tested. [ABSTRACT FROM AUTHOR]

The influence of the oxydiacetate (ODA) and thiodiacetate (TDA) ligands on the physicochemical and biological properties of the oxidovanadium(IV) ternary complexes of the VO(L)(B) type, where L denotes ODA or TDA and B denotes 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen), has been investigated. The stability of the complexes in aqueous solutions, assessed based on the potentiometric titration method, increases in the following direction: VO(TDA)(bipy) < VO(ODA)(bipy) < VO(TDA)(phen) < VO(ODA)(phen). Furthermore, the influence of the TDA and ODA ligands on the antioxidant activity of the oxidovanadium(IV) complexes toward superoxide free radical (O ), 2,2′-azinobis(3-ethylbenzothiazoline-6 sulfonic acid) cation radical (ABTS) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) has been examined and discussed. The reactivity of the complexes toward O increases in the following direction: VO(TDA)(phen) < VO(TDA)(bipy) ≈ VO(ODA)(bipy) < VO(ODA)(phen). The antioxidant activity against ABTS and DPPH free radicals is higher for phen complexes, whereas the thiodiacetate complexes are more reactive than are the corresponding oxydiacetate ones. Finally, herein, the cytoprotective activity of the complexes against the oxidative damage generated exogenously by hydrogen peroxide in the hippocampal neuronal HT22 cell line (the MTT and LDH tests) is reported. In a low concentration (1 μM), the cytoprotective action of thiodiacetate complexes is much higher than that of the corresponding oxydiacetate complexes. However, in the higher concentration range (10 and 100 μM), the antioxidant activity of the complexes is overcompensated by their cytotoxic effect. [ABSTRACT FROM AUTHOR]