The complexation equilibria of L-norleucine and gallic acid were studied in aqueous solutions at 25.00 °C and ionic strength 0.15 mol⋅dm−3 (NaNO3), by means of potentiometry and spectrophotometry. The ferric (FeIII), chromium (CrIII), and cupric (CuII) complexing abilities of L-norleucine and gallic acid, along with their overall stability constants, were obtained with the HYPERQUAD 2008 program from the potentiometric data. The concentration distributions of the various complex species in solution were evaluated and discussed. UV–visible spectroscopic measurements were carried out to give qualitative information about the composition of the complexes formed in these solutions. The cytotoxic activities of the binary and ternary metal complexes of L-norleucine and gallic acid were tested and evaluated against HEp-2 (human laryngeal carcinoma), Daoy (human medulloblastoma), MCF-7 (human breast adenocarcinoma), and WiDr (human colon adenocarcinoma) tumor cell lines. Also, their antioxidant activities were examined by free radical scavenging assay.

Complex Formation Between Ferric(III), Chromium(III), and Cupric(II) Metal Ions and (O,N) and (O,O) Donor Ligands with Biological Relevance in Aqueous Solution

Polycyclic aromatic hydrocarbons (PAHs) in harbour sediment have been determined by means of Shpol'skii fluorometry. Fundamental aspects of this cryogenic high resolution technique are discussed. It provides characteristic spectra of aromatic molecules that can be successfully employed for identification purposes. Extra selectivity is obtained by making use of selective excitation, even with a broad-banded light source. Highly specific quantitative determinations can be achieved, due to the quasi-linear character of the spectra. Deuterated PAHs are suitable as internal standards. Calibration curves with linearity from 10−5-10−6 M down to the detection limit are found, yielding a dynamic range from 2 to 4 decades for the compounds investigated. The reproducibility of the quantitative experiment lies between 6 and 20 per cent. The results obtained with Shpol'skii spectroscopy are in good agreement with data found by a standard method of analysis employing fluorescence detected HPLC.

Quantitative Determination of Polycyclic Aromatic Hydrocarbons in Harbour Sediment via High-Resolution Shpol'skii Spectroscopy

New mixed-ligand salicylaldehyde complexes of Mn(III) bis(phenol) di-amine: Synthesis, electronic and magnetic properties

A facile synthesis of mixed ligand Cu(II) complexes with salicylaldehyde and salicylaldimine ligands and their X-ray structural characterization

A series of Co(II), Cu(II), Zn(II)-thiosalicylic-amino acids of the molecular formula (M-TSA-a.a.) · 2 H2O has been synthesized and characterized by chemical analyses, molar conductance, electronic and i.r. spectral measurements.

Cobalt(II), copper(II), zinc(II)—Amino and thiosalicylic acids ternary complexes

Studies on the mixed ligand complexes involving ligands of biological importance (Ni(II), Zn(II) or Cd(II)-1,10-phenanthroline-α-amino acids)

pH-metric studies on the interaction of Ni(II), Zn(II) or Cd(II) with 1,10-phenanthroline (Phen) or 2,2′-bipyridyl (Bipy) in the presence of phenylalanine (Phe) indicate the formation of 1:1:1 mixed ligand chelates and their monohydroxo derivatives. The addition of Phe takes place after the combination of Phen or Bipy with the metal ion is complete. The formation constants of the resulting complexes have been determined at 30 ± 1 °C and ionic strength (µ) = 0.1 KNO3 and the ternary complexes involving Phen are found to be more stable than the corresponding complexes involving Bipy as primary ligand.

Studies on the Mixed Ligand Complexes Involving Ligands of Biological Importance (Ni(II)/Zn(II)/Cd(II)-1,10-phenanthroline-2,2′ -bipyridyl-phenylalanine)

S. P. Singh

Papers

Studies on the mixed ligand complexes involving ligands of biological importance (Ni(II), Zn(II) or Cd(II)-1,10-phenanthroline-α-amino acids)

Studies on the Mixed Ligand Complexes Involving Ligands of Biological Importance (Ni(II)/Zn(II)/Cd(II)-1,10-phenanthroline-2,2′ -bipyridyl-phenylalanine)