Search results for "Complex formation"
showing 10 items of 50 documents
Complex Formation between Polyelectrolytes and Oppositely Charged Oligoelectrolytes
2016
We study the complex formation between one long polyanion chain and many short oligocation chains by computer simulations. We employ a coarse-grained bead-spring model for the polyelectrolyte chains, and model explicitly the small salt ions. We systematically vary the concentration and the length of the oligocation, and examine how the oligocations affects the chain conformation, the static structure factor, the radial and axial distribution of various charged species, and the number of bound ions in the complex. At low oligocation concentration, the polyanion has an extended structure. Upon increasing the oligocation concentration, the polyanion chain collapses and forms a compact globule,…
Fluorido Complex Formation of Element 104, Rutherfordium (Rf)
2011
We have investigated the cation-exchange behavior of element 104, rutherfordium (Rf), together with its lighter group-4 homologs Zr and Hf, and the tetravalent pseudo-homolog Th in HF/HNO3 mixed so...
Cascade complex formation by phosphate in the cobalt(II)/[30]aneN10 anaerobic system
1993
Abstract The interaction of phosphate with the mono- and binuclear cobalt(II) complexes of [30]aneN 10 (1,4,7,10,13,16,19,22,25,28-decaazacyclotriacontane) has been studied by potentiometry in 0.15 mol dm −3 NaClO 4 solution at 298.15 K under anaerobic conditions. The stable species [CoH 2 ([30]aneN 10 )PO 4 ] + , [CoH 4 ([30]aneN 10 )PO 4 ] 3+ , [Co 2 H([30]aneN 10 )PO 4 ] 2+ , [Co 2 H 2 ([30]aneN 10 )PO 4 ] 3+ and [Co 2 H 3 ([30]aneN 10 )PO 4 ] 4+ , where the phosphate anion is directly bound to the metal ions or acts as a second sphere ligand, are formed and their stability constants have been determined. The results obtained allowed for the selection of suitable conditions for the study…
Preparation and structural studies on the tBu2Sn(IV) complexes with aromatic mono- and dicarboxylic acids containing hetero {N} donor atom
2004
Nine complexes of 'Bu2Sn(IV)(2+) were obtained in the solid state with ligands containing -COOH group(s) and aromatic (N) donor atom. The binding sites of the ligands were identified by FT-IR spectroscopic measurements. It was found that in most cases the -COO- groups are co-ordinated in monodentate manner. Nevertheless, in some of our complexes, the -COO- group forms bridges between two central {Sn} atoms resulting in the formation of an oligomeric structure, a motif that is characteristic only to the nicotinate compound. These pieces of information and the rationalisation of the experimental Sn-119 Mossbauer nuclear quadrupole splittings, Delta, - according to the point charge model forma…
Chemical studies on rutherfordium (Rf) at JAERI
2005
SummaryChemical studies on element 104, rutherfordium (Rf), at JAERI (Japan Atomic Energy Research Institute) are reviewed. The transactinide nuclide261Rf has been produced in the reaction248Cm(18O, 5n) at the JAERI tandem accelerator with the production cross section of about 13 nb. On-line anion-exchange experiments on Rf together with the lighter homologues, group-4 elements Zr and Hf, in acidic solutions have been conducted with a rapid ion-exchange separation apparatus. From the systematic study of the anion-exchange behavior of Rf, it has been found that the properties of Rf in HCl and HNO3solutions are quite similar to those of Zr and Hf, definitely confirming that Rf is a member of …
Effect of high methoxyl pectin on pea protein in aqueous solution and at oil/water interface
2010
International audience; The effect of the addition of high methoxyl pectin on the stability of pea protein isolate emulsions was investigated. Except for low pectin concentrations at acidic pHs where bridging flocculation occurred the addition of pectin improved emulsion stability to pH changes and depletion flocculation induced by maltodextrin addition. The mechanism of pectin induced stability was probed by measuring protein-pectin complex formation in solution, zeta potential of the emulsions droplets and the change in surface viscoelasticity on pectin addition. The phase diagrams of pectin-pea protein isolate in solution and pectin-pea protein-stabilized emulsions were established based…
Studies on proton acceptor ability of SOx-containing compounds
1995
Abstract IR spectra, dipole moments and molar Kerr constants of complexes of phenols with compounds containing SO x groups were studied to establish the structure of the complexes and the parameters characterizing the proton acceptor capability of these compounds. ( μ H , Δ ( mK ), log K and δ 0 ). It has been suggested that the new parameter Δ ( mK ) — the structural additive difference of the molar Kerr constant — makes it possible to determine changes of polarity and polarizability of the systems during complex formation.
Studies on the proton acceptor ability of phosphoryl compounds
1996
Abstract Dipole moments and molar Kerr constants of complexes of phenols with phosphoryl compounds were studied to establish the structure of complexes and parameters characterizing the proton acceptor ability of these compounds. The structures of these complexes and parameters ( μ H , Δ ( mk ) S , log K and δ 0 ) were established. It has been suggested that a new parameter Δ ( mK ) S — structural additive difference of the molar Kerr constant — makes it possible to determine changes of polarity and polarizability of the systems during complex formation.
Mixed complexes of alkaline earth uranyl cabonates: A laser-induced time-resolved fluorescence spectroscopic study
2008
The interaction of the alkaline earth ions Mg2+, Sr2+ and Ba2+ with the uranyl tricarbonate complex has been studied by time resolved laser-induced fluorescence spectroscopy. In contrast to the non-luminescent uranyl tricarbonate complex the formed products show slight luminescence properties. These have been used to determine the stoichiometry and complex stabilities of the formed compounds. As the alkaline earth elements are located in an outer shell of the complex the influence of the type of the alkaline earth element on the stability constant is not very drastic. Therefore all obtained data were averaged in order to derive an common stability constant for the described complexes. These…
Organometallic complexes with biological molecules. XVIII. Alkyltin(IV) cephalexinate complexes: synthesis, solid state and solution phase investigat…
2004
Abstract Dialkyltin(IV) and trialkyltin(IV) complexes of the deacetoxycephalo-sporin-antibiotic cephalexin [7-( d -2-amino-2-phenylacetamido)-3-methyl-3-cephem-4-carboxylic acid] (Hceph) have been synthesized and investigated both in solid and solution phase. Analytical and thermogravimetric data supported the general formula Alk 2 SnOHceph · H 2 O and Alk 3 Snceph · H 2 O (Alk=Me, n -Bu), while structural information has been gained by FT-IR, 119 Sn Mossbauer and 1 H, 13 C, 119 Sn NMR data. In particular, IR results suggested polymeric structures both for Alk 2 SnOHceph · H 2 O and Alk 3 Snceph · H 2 O. Moreover, cephalexin appears to behave as monoanionic tridentate ligand coordinating th…