Competition between different ligands

Complexation of Pu is discussed in terms of the relative stabilities of different oxidation states and the "effective" ionic charge of Pu0 and Pu02+2. An equation is proposed for calculating stability constants of Pu complexes and its correlation with experimental values demonstrated. The competition between inner v outer sphere complexation as affected by the oxidation state of Pu and the pKa of the ligand is reviewed. Two examples of uses of specific complexing agents for Pu indicate a useful direction for future studies. 

Then, contrary to what was reported previously, the olefin dissociates from the zirconium metal complex. This conclusion was further supported by other experimental observations. However, it cannot be completely excluded that competition between dissociative and direct rearrangement pathways could occur with the different isomerization processes studied up to now. Note that with cationic zirconocene complexes [Cp2Zr-alkyl], DFT studies suggest that Zr-alkyl isomerizations occur by the classical reaction route, i.e. 3-H transfer, olefin rotation, and reinsertion into the Zr-H bond the olefin ligand appears to remain coordinated to the Zr metal center [89]. 

Here we exemplify the principles with a substrate interacting competitively with two different ligands (16). This model assumes that there are no interactions between ligands L and I and that the substrate can bind only one additive at a time. The following equilibria hold ... 

Efficient epoxidation of a variety of linear and cyclic alkenes by RuClj/aq. Na(IO )/(bpy)/CH2CyO-5°C/15 h was observed [735] 5-methyl- or 3,4,7,8-tetram-ethyl-phenanthroline can replace (bpy) [736], The active species when (bpy) is present is probably franx-Ru(0)2(bpy) 103(011)3 [567, 568], Competition between epoxidation and cleavage of fran -stilbene with bidentate ligands (pyridine, oxazo-line, oxazolidine and thiophene), containing two different nitrogen heterocycles either linked or separated by a spacer together with RuCyaq. Na(IO )/CH3Cy2°C was reported [737],... 

If CL, CM and pH are kept the same for a series of different cations, the position of equilibrium in equation (6a) would depend on the value of the formation constant, (3 , for the metal complex in question and the extent of precipitation on its solubility product, K. The more stable the complex and the lower its solubility in water, the greater the extent of precipitation. Essentially there is a competition between cations M"+, and protons, H+, for the free ligand anion Ox. ... 

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