Stability constants prediction

Although this is more positive than the maximum value of -14.7 indicated by Baes and Mesmer (1976), it is not inconsistent with that value. With the stability constant predicted using the UTMIC, the CsOH(aq) species would not become important until the hydroxide concentration is in excess of 2 molkg , where the increase in ionic strength would induce a reduction in the stability constant. 

Strohmeier W (1968) Problem und Modell der homogenen Katalyse. 5 96-117 Sugiura Y, Nomoto K (1984) Phytosiderophores - Structures and Properties of Mugineic Acids and Their Metal Complexes. 58 107-135 Sun H, Cox MC, Li H, Sadler PJ (1997) Rationalisation of Binding to Transferrin Prediction of Metal-Protein Stability Constants. 88 71-102 Swann JC, see Bray RC (1972) II 107-144... 

To predict the complexation behavior of ligands at physiological pH, the protonation constants of the ligand have to be considered by using conditional stability constants. Conditional stability... 

Using these properties, a number of species have been placed in the hard, soft, or borderhne categories in Table 3.2. This table can be used to predict, at least qualitatively, the strength of complexation as measured by the stability constants. For example, Pu is a hard acid, F, a hard base, and T, a soft base. This leads to the prediction that log PdPuF O would be larger than log PdPuFOi the experimental log (3i values are 6.8 and <1.0, respectively. By contrast, since Cd is a soft acid, log Pi(CdF ) could be expected to be less than log (3i(CdT) the respective values are 0.46 and 1.89. However, many metals of interest such as... 

The change in bond A is comparable with that, 155- -180°, predicted by Prestegard and Chan (60) from high resolution n.m.r. spectroscopy. Their other observations on solutions, i. e. approximately S4 symmetry and dehydration of the complexed potassium agree with the crystallographic results. 13C n.m.r. spectroscopy (d>7) shows no difference between the ammonium and the alkali metal complexes and does not explain the high stability constant of the ammonium complex1). 

Dale Margerum Ralph Wilkins has mentioned the interesting effect of terpyridine on the subsequent substitution reaction of the nickel complex. I would like to discuss this point—namely the effect of coordination of other ligands on the rate of substitution of the remaining coordinated water. However, before proceeding we should first focus attention on the main point of this paper-which is that a tremendous amount of kinetic data for the rate of formation of all kinds of metal complexes can be correlated with the rate of water substitution of the simple aquo metal ion. This also means that dissociation rate constants of metal complexes can be predicted from the stability constants of the complexes and the rate constant of water exchange. The data from the paper are so convincing that we can proceed to other points of discussion. 

In general, the formation constants of metals with a specific ligand follow the predicted trend and increase in step with increasing metal hardness. Mg, Al, and Mn complexes, however, do not follow this trend. The stability constants of Mg and Al are well established and thus, their anomalous behaviour may indicate the limitation of this simple correlation when comparing A metals (Mg, Al) with d-transition elements (Fe). The data for Mn need to be thoroughly reviewed before any conclusions can be drawn. 

The factors that determine the value of the stability constant depend on the nature of the metal and ligand. Attempts at introducing a systematic approach in predicting the stability of complexes have shown that certain ligand atoms prefer to bind particular metal ions. The various concepts for the rationalisation of this preference have been developed by Sidgwick Ahrland et al. and more recently Pearson Although these concepts contain some unresolved contradictions, they are nonetheless useful in giving an idea of the type of complex expected and the possible sequence of the stability. 

Proposed species in granitic groundwater are given in Table VIII. Since many of the relevant stability constants are not known, especially for actinide complexes with OH", CO32" and PO ", any final conclusive predictions of speciation in groundwater are impossible. 

No stability constants for equations (27) and (29) are available, although an estimate for log j84 of 27 has been made.499 The equilibrium between silver(II) and protons competing for N donors was predicted to be set up fairly quickly, just as for copper(II), and the tacit assumption in early work that silver(II) was kinetically inert in nitric add media was incorrect. 

Thiocyanate. — On the basis of /-orbital hybridization Diamond [351] predicted the formation of stronger actinide complexes with thiocyanate ion than for the rare earths. Subls and Chopfin [352] have studied the ion exchange behaviour of many actinide and rare earth thiocyanate complexes and have shown that europium is eluted much sooner than americium from Dowex-1 with ammonium thiocyanate. The stability constants for the formation of MSCN2+ and M(SCN)2 complexes for Nd3+, Eus+, Pu3+, Am3+, Cm3+, and Cf34 have been measured [353] and are tabulated in Table 25. It is apparent from the table that the formation... 

Empirical approaches to predict the stability constants of metal complexes in solution (mostly in water) are discussed in the book by Kumok11 and in reviews by Hancock and Martell,9 Dimmock et al.,7 Hancock,8 and Hay.10 Generally, two types... 

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