Chelate complex, distribution ratio

Distribution ratio for a single chelate complex If we assume that the only form of the metal in the organic phase is the chelate ML , and if we neglect the formation of lower complexes in the aqueous phase, the distribution ratio of the chelate is... 

An early report of the stereospecific reaction between (/ )(-l-)-tartaric or (/ )(-I-)-malic acid and [Co(C03)(phen)2]Cl at ambient temperature has been refuted and both A- and A-[Co (/ )L (phen)2]" ions (233) are formed. The distribution ratio A(J )/A(/ ) = 0.38 for the (i )-tartrate complex. Using [(5o(Cl)2(phen)2]Cl at 60 °C and Na(-t-)-tartrate the ratio is 0.70, but thermodynamic distributions remain unknown. A(ii) and A(i ) diastereoisomers of both acids have recently been isolated and characterized by CD and 360 MHz H NMB. The reaction of meso-tartaric acid results in four diastereoisomeric possibilities (depending on which asymmetric carbon is in the chelate ring) and all four have been separated... 

The percent extraction of a complex or a chelate is related to the distribution ratio by... 

For effective extraction of a metal ion from the aqueous (Maq) into the organic phase (Morg) it is necessary to form, usually by chelate reaction, non-polar complexes. If organic solvents, inmiscible with water, are mixed with seawater solution, then the distribution ratio (D) of the metal species is given by ... 

The Nernst distribution law applies to metal complexes, but their distribution ratios are determined by several interrelated equilibria. As in the case of organic acids and bases, the efficiency of extraction of metal chelates is pH dependent, and for some ion-association complexes, notably oxonium systems (hydrogen ions solvated with ethers, esters or ketones), inorganic complex ions can be extracted from concentrated solutions of mineral acids. 

The product distribution is determined by the ratio of the two alkyl groups, R1 and R2, present in the reaction system and their reactivities, only. Empirically obtained relative reactivities are methyl ethyl n-bu-tyl = 1 20 8. The product ratio is neither influenced by the order of mixing nor the conditions, including temperature, of mixing the initially formed DAIB-chelated alkylzinc complex with benzaldehyde and the second alkylzinc agent. 

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