Monoacetato complex

Studies on the acetate complexes of Nd(III) by Choppin et al. using the hypersensitive transition showed that the formation of the monoacetato complex did not alter the intensity of the band but produced a small red shift. Formation of the diacetato complex produced marked changes in intensity and red shift. These changes were interpreted as due to the penetration of the second acetate anion into the inner coordination sphere and causing a structural change [203]. These results may be interpreted as (i) initial addition of acetate forms an ion-pair complex, (ii) further addition of acetate results in entry of acetate into the inner coordination sphere of Nd(III) ion. Complex formation of Nd(III) with EDTA and NTA ligands was studied by the analysis of the bands due to 4G7/2 4Io/2 and... 

With the corresponding L-prolinato-JV-monoacetato complex, [Co(L-proma ], only a trans isomer and a cis isomer were detected this is explained by a unique R configuration of the nitrogen donor atom and by the preferential facial coordination of the L-proma ligand Similar experiments were carried out with [Co(L-promp)2] ,... 

This mechanism of lead-metal exchange on EDTA is believed to proceed by an associative (Se2) process, with the formation of dinuclear intermediates in which each metal is coordinated to one of the iminodiacetate halves of the EDTA molecule (273). Tanaka et al. (277, 278) showed that the presence of buffer molecules in solution slows the rate of metal exchange by limiting Pb accessibility but proposed that the buffer does not alter the overall mechanism. Consequently, it is necessary to include the kinetics of metal-buffer coordination in calculations in order to produce meaningful rate constants (275, 276, 278, 280). Studies of Pb(ll) exchange with Co -EDTA confirm that both hydrated and monoacetato Pb(II) ions take part in the substitution reaction, but substitution reactions with monoacetato lead complexes occur more slowly than those with hydrated lead ions (280, 281). 

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