Glycine, formation constants with

The equilibrium formation constants for the 1 1 complexes of Hf with glycine and serine in solutions of pH 2 have been determined as 31 and 18, respectively, and the HfO -amygdalic acid complex, [HfO PhCH(0)- 02)2] , has been obtained in aqueous solutions of pH 7—10.5. The stability constants of the 1 1 complexes of ZrO with iVh/ -ethylenediamine-bis(succinic acid) and Nh/ -ethylenediaminebis(glutaric acid) have been determined. ... 

Because of the ability of ion-selective electrodes to measure the activity of free ions, it has been possible to obtain thermodynamic formation constants and to have information on the number of binding sites and the stoichiometries of complexes. Thus, formation constants have been calculated for copper(II) complexes with glycine, glutamic acid and tris(hydroxymethyl)aminomethane [420,421]. 

As may be seen from Figure 3, first order plots based on the conversions obtained by both methods were linear with slopes in close agreement. The apparent rate constant is 0.57 h"1 based on H2 evolution and 0.54 h"1 based on the formation of glycine salt thereby indicating that it is valid to use the simpler H2 evolution measurements when measuring the effects of process variables on the reaction. 

Schiff s base formation occurs by condensation of the free amine base with aldehyde A in EtOAc/MeOff. The free amine base solution of glycine methyl ester in methanol is generated from the corresponding hydrochloride and triethylamine. Table 4 shows the reaction concentration profiles at 20-25°C. The Schiffs base formation is second order with respect to both the aldehyde and glycine ester. The equilibrium constant (ratio k(forward)/ k(reverse)) is calculated to be 67. 

It has been tacitally assumed in this discussion that the second-order formation rate constants measure the simple water substitution process. Although this must apply when unidentate ligands replace coordinated water, a composite process could describe the replacement by multidentate ligands. However, consideration of rate constants for successive formation and dissociation processes suggests that the overall rate of complex formation with flexible bidentate (and probably multidentate) ligands such as diamines, dipyridyl, glycine is probably determined by the rate of expulsion of the first water molecule from the metal aqua ion (56, 80, cf. 3 and 84). 

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