Debjani Chakraborty

Intramolecular interligand interactions in Cu(II) ternary complexes involving dipeptides and amino acids

The formation constants of the mixed ligand complexes of the type (CuAL), where A refers to glycylglycine (A1), glycyl-l-alanine (A2), and glycyl-l-leucine (A3) and L refers to α-alanine (L1), phenylalanine (L2), tryptophan (L3), tyrosine (L4), and l-dopa (L5), were determined in 1:1 (v/v) dioxan-water medium at 30°C and I = 0.2 M (NaClO4) using an SCOGS computer program. The influence of the noncoordinated aromatic side groups of the amino acids on ternary complex formation is discussed.

Synthesis, characterization, DNA binding and cytotoxicity studies of moxifloxacinato complexes

Five metal complexes of the third-generation quinolone antibacterial agent moxifloxacin with Cu(II), Fe(III), Mn(II), Ni(II) and VO(II) have been synthesized and characterized by physicochemical and spectroscopic techniques. In these complexes, moxifloxacin acts as a bidentate deprotonated ligand bound to the metal through ketone and carboxylate oxygens. The interactions between the metal complexes and calf thymus DNA have been studied by UV–Vis, circular dichroism and cyclic voltammetry. Fluorescence competitive binding studies with ethidium bromide (EB) demonstrate the ability of the complexes to displace the EB bound to DNA. The cytotoxicities of the complexes have been evaluated on A549 cells by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. [Cu(MFL)2(H2O)2] shows the highest anticancer potency. The apoptosis-inducing activity was assessed by acridine orange/ethidium bromide staining assay.

Cu(II) Complexes of Isoniazid Schiff Bases: DNA/BSA Binding and Cytotoxicity Studies on A549 Cell Line

A series of isonicotinoyl hydrazones have been synthesized via template method and were complexed to Cu(II). The ligands are coordinated to Cu(II) ion through the enolic oxygen and azomethine nitrogen resulting in a square planar geometry. The CT-DNA and bovine serum albumin binding propensities of the compounds were determined spectrophotometrically, the results of which indicate good binding propensity of complexes to DNA and BSA with high binding constant values. Furthermore, the compounds have been investigated for their cytotoxicities on A549 human lung cancer cell. Also the mode of cell death was examined employing various staining techniques and was found to be apoptotic.

Formation and Stabilization of Anisotropic Palladium and Platinum Nanoparticles in Aqueous Polymer Solution Using Microwave Irradiation

Anisotropic palladium and platinum nanoparticles were synthesized by reduction of the corresponding metal ions with hydrazine using polyacrylamide as a stabilizing agent in aqueous medium under microwave irradiation. The formation of particles was confirmed by UV-visible spectroscopy. The size and shape of the particles were determined using transmission electron microscopy. Rapid microwave heating resulted in ‘star-shaped’ palladium nanoparticles, but platinum nanoparticles were observed to be spherical with a distinctly visible 3–4 nm coating of polyacrylamide on their surface, which was not observed for the palladium particles. The Pt nanoparticles were used as a catalyst in the redox reaction.

Interligand interactions in ternary copper(II) complexes of dipeptides and auxins

Abstract The formation constant of the mixed ligand complexes of the type (CuAL) and (CuA H L), where A refers to glycylglycine, glycyl-L-alanine, and glycyl-L-leucine; and L refers to indole acetic acid, indole propionic acid, and indole butyric acid. They were determined in 1:1 (V/V) dioxan-water medium at 30°C and I = 0.2 M (NaClO 4 ), using scogs computer program. The astatistical stabilization of the ternary complexes has been attributed to intramolecular hydrogen bond formation between the two ligands.

Ternary complexes of substituted catechols and dipeptides with copper(II)

The formation constants of the ternary complexes [CuA(L)], where A refers to the monoanions of glycylglycine (A1), glycyl-L-alanine (A2), or glycyl-L-leucine (A3) and L to the dianions of catechol (L1), pyrogallol (L2), 4,5-dihydroxybenzene-1,3-disulphonic acid (L3), or naphthalene-2,3-diol (L4), were determined by potentiometric titration in a queous medium at 30°C and I= 0.2 mol dm–3(NaClO4) using the SCOGS computer program. The enhanced stability of the ternary complexes is attributed to possible hydrogen bonding between the two ligands through a water molecule.