Mixed-ligand Copper(II) Complexes: Investigation of their Spectroscopic, Catalysis, Antimicrobial and Potentiometric Properties

Abstract

Schiff base ligands HL 1 -HL 6 have been prepared from the reaction of 2,6-diformyl-4-t-butylphenol and 2,6-diformyl-4-methylphenol with various aromatic amines in ethanolic solution. The Schiff base ligands 2,2¢-dipyridine (dp) mixed-ligand Cu II complexes have been obtained. Mixed-ligand Cu II complexes containing the dp ligand have ionic nature and they conduct the electricity in solution media. The complexes have been obtained in two different forms: one of them is [Cu 2 (L n )Cl 3 ] (n: 1, 2, 3, 4, 5 and 6) and other complexes have the general formula [Cu 2 (L n )(dp) 2 ]3Cl. Ligands and their complexes have been characterized by elemental analyses, FT-IR, electronic spectra, molar conductance, 1 H( 13 C)-n.m.r. and mass spectral data. Their stoichiometric protonation constants have been determined potentiometrically in dioxan using a combined pH electrode at 25°C, under a nitrogen atmosphere. For the calculation of the protonation constants, PKAS computer programme has been used. The effects of the substituents on the protonation constants and the additivities of these effects are discussed. The antimicrobial activity studies of the ligands and their complexes have been studied against the Bacillus megaterium, Micrococcus luteus, Corynebavterium xenosis, Enterococcuc faecalis, bacteria and Saccoramyces cerevisia, yeast. The catalytic properties of the complexes have been studied on the ascorbic acid, catechol and 2,6-di-t-butylphenol substrates. Thermal behaviour of the complexes has been studied by thermal techniques.

Cobalt(II) and Manganese(II) Complexes of Novel Schiff Bases, Synthesis, Charcterization, and Thermal, Antimicrobial, Electronic, and Catalytic Features

“…For the complex compounds the d-d transitions were observed between 560 nm and 640 nm, and the bands observed in the 395-367 nm range for these complexes can be attributed to the charge transfer bands from ligand to metal or from metal to ligand centre [46,47]. The - * and - * transitions of the synthesized ligands and complexes were observed in 202-334 nm region.…”

“…The magnetic moment values for cobalt complexes were recorded as 4.35 B.M. and 4.89 B.M., which are characteristic values for tetrahedral cobalt complexes [46,47]. The manganese(II) complexes gave 5.85 B.M.…”

“…The bacteria were first incubated at 37 ± 0.1 ∘ C for 24 h in nutrient broth (Difco), and the yeasts were incubated in Sabouraud dextrose broth (Difco) at 25 ± 0.1 ∘ C for 24 h. The cultures of the bacteria and yeast were injected into the Petri dishes (9 cm) in the amount of 0.1 mL (McFarland OD: 0.5, 1.5 × 10 8 bacteria/mL and 1.5 × 10 6 yeast/mL) [38,39,41,42]. Then, Mueller Hinton agar and Sabouraud dextrose agar (sterilized in a flask and cooled to [45][46][47][48][49][50] ∘ C) were homogeneously distributed onto the sterilized Petri dishes in the amount of 25 mL. Finally, 2 mg of each chemical compound dissolved in ethanol was placed inside the sterilised antibiotic discs.…”

Synthesis, spectroscopic studies of novel N-substituted phthalimides and evaluation of their antibacterial, antioxidant, DNA binding and molecular docking studies

“…The molecular docking approach can be used for understanding the intermolecular interactions between proteins and ligands (Huang and Zou, 2010). Many studies have been investigated regarding the biological activities of Schiff bases including their anticancer (Shukla et al, 2013), antimicrobial (Tumer et al, 2006) and antifungal (Tumer et al, 1999) activities. The biological activities of phthalimide ana-logues have been paid more attention long before, however, the antimicrobial activity of phthalimide linked to Schiff bases have few been reported (Al-Azzawi and Al-Razzak, 2014).…”

Synthesis, Antibacterial and Antifungal Activities of Some Cobalt(II) and Nickel(II) Complexes of Thiosemicarbazones

“…Complexes containing chelating ligands, which show promising biological activity, have been recently studied by ourselves [1][2][3][4][5][6][7][8][9][10][11] and others. [12][13][14][15][16][17][18][19][20][21][22] We have investigated the synthesis and characterization of cobalt(II), [1][2] nickel(II), 2-3 oxovanadium(IV), 4-5 platinum(II) 6 and some lanthanide(III) 7 complexes that contain a range of ancillary ligands such as semicarbazones, 7 thiosemicarbazones.…”