Metal complexes with functionalised 2,2′-dipicolylamine ligand containing an antioxidant 2,6-di-tert-butylphenol moiety: synthesis and biological studies

Abstract

A series of Zn, Mn, Fe, Co, and Ni complexes ([MX2L], X = Cl, OAc) of the novel di-(2-picolyl)amine ligand L with an antioxidant 2,6-di-tert-butylphenol pendant were synthesized and characterized by elemental analysis, IR, multinuclear NMR spectroscopy, MALDI-TOF mass spectrometry and the molecular structures of [ZnCl2L] and [MnCl2L] were established by X-ray crystallography. The chemical oxidation of complexes with a 2,6-di-tert-butylphenol fragment to the phenoxyl radicals was studied by means of ESR method. The antioxidant radical scavenging activity of the complexes was measured spectrophotometrically using a DPPH-test and linoleic acid peroxidation. The electron transfer reactions were examined in CUPRAC tests and as the inhibition of an enzymatic reaction involving the generation of a reactive oxygen species (superoxide radical-anion) by xanthine oxidase. The lipoxygenase (LOX) inhibition activity of the studied compounds was evaluated. The in vitro biological experiments were performed by using rat brain homogenates. The role of the phenol fragment and metal was found to be essential in antioxidant activity.

Oxovanadium(IV) and ruthenium(II) carbonyl complexes of ONS‐donor ligands derived from dehydroacetic acid and dithiocarbazate: Synthesis, characterization, antioxidant activity, DNA binding and in vitro cytotoxicity

“…The TEAC values of the ligands were found to be 0.50 and 0.76, with higher values of 0.60 and 0.96 for their corresponding oxovandium(IV) complexes 1.1 and 2.1 compared to those for the other complexes (Table ). This indicates that vanadium(IV) ion in 1.1 and 2.1 has greater ability for electron transfer, while for the other metal complexes there is a low electron transfer capacity …”

[2,5-Bis(2,2′-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene]dichloridomanganese(II): from a mononuclear compound to a three-dimensional supramolecular framework through C—H...Cl hydrogen bonds and π–π stacking interactions

“…However, the dihedral angle between the planes of rings C (atoms N4/C18-C22) and D (atoms N3/C13-C17) is 26.65 (12) . The Mn-Cl bond lengths (Table 2) are in the normal range for compounds reported in the literature (Jones et al, 2006;Milaeva et al, 2013).…”

Comparative study of in vivo impact of water-soluble and lipophilic forms of dipicolylamine containing a 2,6-di-tert-butylphenol moiety on the oxidative status of rat tissues

“…8 The water soluble form 2 was prepared from compound 1 and aqueous HCl in methanol. The structure was confirmed by IR and NMR spectroscopy and elemental analysis data.…”