Miroslava Puchoňová

Methyl- and methoxysalicylatocopper complexes with 2-pyridylmethanol: Synthesis, spectral properties, structure and EPR characterization in solid-state and in solution

AbstractThe syntheses and characterizations of salicylatocopper(II) complexes of the formula Cu(X-sal)2(2-pyme)2 (X = 3-MeO (1), 4-MeO (2), 3-Me (3), 4-Me (4) and 5-Me (5), where 3-MeOsal− = 3-methoxysalicylate, 4-MeOsal− = 4-methoxysalicylate, 3-Mesal− = 3-methylsalicylate, 4-Mesal− = 4-methylsalicylate, 5-Mesal− = 5-methylsalicylate anion, and 2-pyme = 2-pyridylmethanol) are reported. The composition was determined by elemental analysis, and ligand coordination modes have been determined by spectroscopic methods (IR, UV-VIS). The crystal structure determination of [Cu(3-MeOsal)2(2-pyme)2] (1) and [Cu(5-Mesal)2(2-pyme)2] (5) have confirmed conclusions originally based on spectral data. EPR measurements of frozen water/methanol solutions containing different copper(II): 2-pyme molar ratios have indicated presence of complexes with only two nitrogen donor atoms bonded to each central atom.

SOD mimetic activity of salicylatocopper complexes

Investigation of salicylatocopper complexes in the presence of a nitrogen donor ligand is a growing research area due to the interesting mimetic activities of such complexes. Here, three X-salicylatocopper (where X = 3-methyl, or 4-methoxy) complexes with three different N-donor ligands, [Cu(μ-menia)(3-Mesal)2(menia)(H2O)]2 (I), Cu(3-Mesal)2(denia)2(H2O)2 (II), Cu(4-MeOsal)2(2-pyme)2 (III), are presented (where 3-Mesal = 3-methysalicylate, 4-MeOsal = 4-methoxysalicylate, menia = N-methylnicotinamide, 2-pyme = 2-pyridylmethanol). The complexes were characterized by elemental analysis, IR and UV-VIS spectrophotometry. Cyclic voltammetry and the superoxide dismutase activity of the prepared complexes in solution were measured and the complexes were characterized by means of the inhibition concentration IC50. In addition, the superoxide dismutase (SOD) activity of these complexes was compared with those of the parent ligand copper acetate, native SOD enzyme, and the related copper complexes containing non-steroidal anti-inflammatory drugs. The resulting SOD activity was correlated to the composition, structure and redox stability of the prepared complexes. The best value of the inhibition concentration was found for complex I (IC50 = 2.24 µM), which classifies this complex into a group of good superoxide scavengers.

Methyl- and methoxysalicylatocopper complexes with 2-ethylbenzimidazole

Abstract Four new compounds of formulae [Cu(3-Mesal)2(etbzim)2] (1), [Cu(4-Mesal)2(etbzim)2] (2), [Cu(4-MeOsal)2(etbzim)2] (3), [Cu(5-MeOsal)2(etbzim)2] (4) where 3- or 4-Mesal = 3- or 4-methylsalicylate anionic ligand, 4- or 5-MeOsal = 4- or 5-methoxysalicylate anionic ligand, etbzim = 2-ethylbenzimidazole) have been prepared and characterised by elemental analysis and available spectral methods (EPR, UV-vis and IR spectra). EPR spectra of all measured complexes are axial symmetry. Other spectral methods led to conclusion that all prepared complexes probably contain the etbzim ligand coordinated in equatorial plane together with the asymmetrically bonded salicylato anions thus giving {CuN2O2O’O”} chromophore. The supposed structural motive for all prepared complexes might be simmilar to those benzoate complexes with benzimidazole [Cu(4-OHbz)2(bzim)2] and [Cu(4-Mebz)2(bzim)2] (4-OHbz = 4-hydroxybenzoate, 4-Mebz = = 4-methylbenzoate), but similarity with polymeric salicylate complex [Cu(sal)2(bzim)2]n cannot be excluded.

Methyl- and methoxysalicylatocopper(II) complexes with 2-aminomethylpyridine

Abstract As a part of our systematic study of copper(II) complexes in presence of biologically active ligands, we concluded to realize experiments with methyl- or methoxysalicylatocopper(II) complexes in presence of 2-aminomethylpyridine (ampy) ligand. This has resulted in four new complexes of the formula Cu(XSal)2(ampy) (where XSal are 3-MeSal− = 3-methylsalicylate, 4-MeSal− = 4-methylsalicylate, 5-MeSal− = 5-methylsalicylate, or 4-MeOSal− = 4-methoxylsalicylate anions). The synthesis, elemental analysis and spectral properties (EPR, electronic and infrared) are reported. The Cu(II) atom in all four complexes is probably coordinated by two nitrogen atom of the bidentate chelating ampy as well as monodentate and/or highly asymmetrically chelating salicylate anions. Based on the analyses it was concluded that the structure of these new compounds could be similar to [Cu(HCOO)2(ampy)], or [Cu(CH3COO)2(ampy)] that are reported in the literature.

Nitrosalicylatocopper(II) complexes with chelating pyridine derivatives

Abstract Three new nitrosalicylatocopper(II) complexes have been prepared and characterized. Compounds of the composition Cu(5-NSal)2(2-ampy)2 (1), Cu(5-NSal)2(2-hmpy)2 (2) and Cu(3,5-DNSal)2(2-hmpy)2 (3), where 2-ampy = (2-aminomethyl)pyridine, 2-hmpy = (2-hydroxymethyl)pyridine, 5-NSal = 5-nitrosalicylate anion and 3,5-DNSal = 3,5-dinitrosalicylate anion, were characterized by elemental analyses, EPR and IR spectroscopy. EPR spectra are consistent with the dx2-y2ground electronic state. Spectral properties have shown “classic” monodentate coordination of 5-nitrosalicylate anion. Similarly, bonding mode of the 3,5‑dinitrosalicylate anion in (3) is assumed to be unidentate via the carboxyl group, which is surprising compared with the previously studied complex, where the preferred coordination via the phenolate group anion was observed.

Some aspects of dimeric metylsalicylatocopper(II) complexes preparation

Abstract A systematic study of the preparation of methylsalicylatocopper(II) complexes with or without N-donor ligand has resulted in three new dimeric complexes formation. The investigation has been targeted to two main aspects: the conditions of dimeric complexes preparation and the properties of obtained products. The common stoichiometric formula for all three complexes is Cu(x-MeSal)2(H2O)(ACN)z (where x-MeSal = 3- or 4-methylsalicylate anion, ACN = acetonitrile and z = 0, 1). Used spectral measurements mainly EPR spectroscopy gave the proof about the existence of dimeric “paddle-wheel” units in all three complexes. Moreover, it was concluded that acetonitrile molecules are more probably bonded to copper(II) atoms in apical positions of dimeric units. The water molecules are in coordination sphere only in the case when acetonitrile is not present. However data show that presence of 4-methylsalicylate anions led to strengthening of Cu-N bonds.