نتایج جستجو برای: protonation and complexation constants
تعداد نتایج: 16832868 فیلتر نتایج به سال:
A new Schiff base ligand, 2,2'-{pyridine-2,6-diylbis[nitrilo(E)methylylidene]}bis(4 bromophenol),has been synthesized by reaction of the 2,6-diamino pyridine with 5-bromo salicylaldehyde at ethanolunder refluxing. The structure of the synthesized compound resulted from the IR, 1HNMR, MS andUV spectroscopy and elemental analysis data. Formation Constant (kf) value of it’s complexes withCu2+, Ni2...
A fruitful combination of potentiometry, absorption spectrophotometry, ESMS and 1H NMR enabled the characterisation of two caesium complexes with norbadione A and the determination of the respective stability constants of a mononuclear and a dinuclear caesium complex at pH approximately 6; a preliminary study allowed the assignment of five protonation sites of this pigment; a positively coopera...
fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...
ATCUN (amino terminal Cu(II) and Ni(II) binding) motifs chelate ions strongly. However, the impact of phosphorylation neighboring residues on such complexation has not been elucidated. The copper(II) dissociation constants original phosphorylated peptides from human histatin-1 serum albumin were compared using spectroscopic methods. Phosphorylation markedly weakened binding. Thus, these results...
we have two part in this thesis, at first: the interaction of native calf thymus dna (ct-dna) with two anthraquinones including quinizarin (1,4- dihydroxy anthraquinone) and danthron (1,8- dihydroxy anthraquinone) in a mixture of 0.04 m brittone-robinson buffer and 50% of ethanol were studied at physiological ph by uv-vis absorption, florescence, circular dichroism spectroscopic methods, viscos...
The complexation of zinc (II) with dopamine has been investigated by spectrophotometric measurements in mixed solvent system at an ionic strength of 0.2 mol*dm-3 sodium chloride, employed (25± 0.1° C) at pH ranges of ~6 to ~7 with a high ratio of ligand to metal.
A family of ligands derived from bis(amino amides) containing aliphatic spacers has been prepared, and their protonation and stability constants for the formation of Cu(2+) complexes have been determined potentiometrically. Important differences are associated to both the length of the aliphatic spacer and the nature of the side chains derived from the amino acid. In general, ligands containing...
We use a combination of spectroscopic, calorimetric, viscometric and computer modeling techniques to characterize the binding of the aminoglycoside antibiotic, tobramycin, to the polymeric RNA duplex, poly(rI).poly(rC), which exhibits the characteristic A-type conformation that is conserved among natural and synthetic double-helical RNA sequences. Our results reveal the following significant fe...
The binding dynamics of the 2-aminoanthracenium cation (AH(+)) and 2-aminoanthracene (A) with cucurbit[7]uril (CB[7]) was studied using stopped-flow experiments. The kinetics was followed by measuring the fluorescence changes over time for AH(+) and A, which emit at different wavelengths. The studies at various pH values showed different mechanisms for the formation of the AH(+)@CB[7] complex, ...
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