Search results for "Complex formation"
showing 10 items of 50 documents
1981
Equilibrium Studies in Natural Fluids. A Chemical Speciation Model for the Major Constituents of Seawater.
1994
AbstractThe speciation of CI−, OH− and SO42- in synthetic sea water has been studied by Potentiometric measurements (pH-metric and ISE-Na methods) and by literature data analysis, using a well tested complex formation model. Stability constants, together with distribution of hypothesised species in synthetic sea water, as a function of temperature and salinity, are reported. The speciation model proposed in this work is discussed on the basis of chemical and statistical considerations. Comparison with some literature sea water models is given.
Polymerisation von acrylnitril, methylmethacrylat und einigen substituierten acrylnitrilen mit anorganischen nitraten. Zur polymerisation von acryini…
1968
Die radikalische Polymerisation von Acrylnitril (AN), Methacrylnitril, α-Chloracrylnitril, Crotonsaurenitril und Methylmethacrylat wird unter Bestrahlung bei 60°C in An wesenheit von AgNo3 untersucht, und die Polymerisationsgeschwindigkeiten werden verglichen. Unterschiede in der Polymerisationsfahigkeit einzelner Monomerer lassen sich teilweise auf Komplexbildung mit AgNO3 zurackfahren. Es werden einige andere anorganische Nitrate als Initiatoren eingesetzt; ihre Aktivitat entspricht der Stellung der Kationen in der Spannungsreihe. Als Teil der Initiierungsreaktion wird eine Reduktion des Metallions angenommen; daher kann eine Abnahme der Kationenkonzentration bei AgNO3 und besonders bei C…
Speciation of organic matter in natural waters. Interaction of polyacrylates with the major cation components of seawater
2004
The speciation of some high molecular weight polycarboxylates was studied in different ionic media. Polyacrylates here investigated (W=2.0, 5.1 and 20.0 kDa) form weak species with alkali metal cations (K=102 mol l1, t=25 jC, I=0 mol l1) and quite stable complexes with alkaline earth metal cations (K>106 mol l1, t=25 jC, I=0 mol l1). Results are reported from experiments performed in a multicomponent electrolyte solution simulating the major composition of seawater (artificial seawater). Protonation constants in this medium are expressed as a polynomial function of S1/2 (S=salinity) and the sharp lowering with respect to values obtained in non-interacting aqueous tetraalkylammonium salts ca…
Polymere Charge-transfer-Komplexe auf der Basis von Polyvinylalkoholacetalen
1978
Poly[2-(1-naphthyl)-1,3-dioxan-4,6-diylmethylene] (3), poly[2-(2-naphthyl)-1,3-dioxan-4,6-diylmethylene] (5), 1-naphthalenecarbaldehydetrimethyleneacetal (7) and 2-naphthalenecarbaldehydetrimethyleneacetal (8) were synthesized and characterized by UV- and fluorescencespectroscopy. In addition triplet-triplet absorption maxima and triplet-lifetimes were determined by flash technique. The naphthalene derivates were found to act as donors in the charge-transfer complex formation with such electron acceptors as tetracyanoethylene, 2,5-cyclohexadien-1,4-diylidenedimalonodinitrile and 2,4,5,7-tetranitro-9-fluorenone. The equilibrium constants of the charge-transfer complexes were determined spect…
A new selective fluorogenic probe for trivalent cations.
2012
[EN] A new selective chromo-fluorogenic probe for Fe 3+, Cr 3+ and Al 3+ is reported. Detection limits are in the ¿M range and the fluorogenic sensing ability could be observed by the naked eye when illuminated with UV-light. No response is observed with divalent cations. © 2012 The Royal Society of Chemistry.
The complex formation equilibria between Cd(II), Pb(II) and iminodiacetic acid in NaClO4 0.93 Mw at 25°C
2010
The peculiarities of the radiation damage accumulation kinetics in the case of defect complex formation
2020
Abstract The kinetics of radiation defect accumulation under irradiation by heavy particles is theoretically analysed under the assumption of defect complex genesis, particularly, the ones of anion and cation vacancies. The obtained analytical mathematical model and revealed peculiarities of radiation dose dependencies can be used for analysis of the experimental results for different crystalline materials for solid-state electronics and photonics.
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…
Speciation of organotin compounds in NaCl aqueous solution. Interaction of mono-, di- and triorganotin(IV) cations with nucleotides 5’ monophosphates
2004
Formation constants for complex species of mono-, di- and tri-alkyltin(IV) cations with somenucleotide 5-monophosphates (AMP, UMP, IMP and GMP) are reported, atT=25◦CandatI=0.16 mol l−1(NaCl). The investigation was performed in the light of speciation of organometalliccompounds in natural fluids in the presence of nucleotides whose biological importance is wellrecognized. The simple and mixed hydrolytic complex species formed in all the systems investigatedin the pH range 3–9 are (L=nucleotide; M=organotin cation RxSn(4−x)+, withx=1to3):ML+,ML(OH)0and ML(OH)2−for the system CH3Sn3+–L (L=AMP, IMP, UMP); ML0and ML(OH)−for the system (C2H5)2Sn2+–L (L=AMP, IMP, UMP); ML−, ML(OH)2−,MLH0and M2L(O…