Metallkomplexe mit Polyaminen VII: Diamine und Silber(I)

Abstract

The equilibria in solutions containing each one of the diamines H2N(CH2)nNH2, with n = 3 (“pn”), n = 4 (“tn”), n = 5 (“cad”), piperazin (“pip”) and triethylenediamine (“enpip”) in presence of an excess of silver nitrate have been investigated. Values are given for the stability constants of the complexes: Ag(pn)+, Ag(tn)+, Ag(cad)+, Ag(pip)+, Ag(enpip)+, the hydrogen complexes: Ag(Hpn)+2, Ag(Htn)+2, Ag(Hpip)+2 and the bimetallic complexes: Ag2(pn)+2, Ag2(pip)+2.

Voltammetry as a Virtual Potentiometric Sensor in Modeling of a Metal‐Ligand System and Refinement of Stability Constants. Part 1. Polarographic and Glass Electrode Potentiometric Study of a Dynamic Cd‐Glycine System

“…Experimental points were fitted with a straight line to establish the value of E8 and a response slope (to the second decimal place) of the GE. The values of E8 and a response slope were later used to calculate pH À log 10 …”

“…The potential of a combination glass electrode and pH À log 10 [H] of solutions were measured to within AE 0.1 mV (AE 0.001 pH unit) with a pHI 72 pH meter (Beckman, Fullerton, CA, USA). A Model 6.0234.100 combination glass electrode (Metrohm) was used.…”

“…All the above methodologies showed very limited field of applications as they were based on a simple data interpretation without involving mass-balance equations. Possibly the most significant contribution in establishing stability constants by polar-ography comes from the school of Schwarzenbach [10,11] who derived a simple equation allowing analysis of systems involving two metal ions competing for a single ligand when fully inert (nonlabile) complex was formed. Among many theories and methodologies described in a book by Crow [12] there is not a single contribution that involves massbalance equations and a typical GEP analytical procedure, e.g., acid-base titration.…”

Solution Equilibria. A Unified Mathematical Treatment of Potentiometric and Polarographic Data in a Metal-Ligand Equilibrium Study at a Fixed Ligand to Metal Ratio and Various pH Values

“…Not surprisingly, there is not a general theory to date that would allow one to study any kind of metal complexes by voltammetry. Instead, several techniques were proposed that were focused either on fully labile [2][3][4], nonlabile [5][6], or inert [7][8][9] metal-ligand systems, simple inorganic ligands [10,11] or polyelectrolytes [7][8][9][12][13][14] etc. All these techniques were developed for the experimental conditions where experiment was performed at fixed pH and in the presence of an access of a ligand.…”

A study of the rare-earth chelate stability constants of some aminopolyacetic acids

“…One of these constants *N'-(hydroxyethyl) ethylenediamine-N, N, N'-triacetic acid must be measured independently to find the absolute value of the other. This method has been used by a number of people for the determination of stable-chelate formation constants (19,20 (31). Solutions were prepared containing known amounts of two lanthanides, one of which was radioactive, and an amount of the chelating agent EDTA which was about half the sum of the concentrations of the two lanthanides.…”