Copper oxalate stability constants

Stability constants have also been determined for oxalate and malonate (Table 39). The succinate [Cr(C4H404)H20]2-2H20 is isostructural with the copper(II) compound.213 ... 

Due to the anionic nature of rhamnolipids, they are able to remove metals from soil and ions such as cadmium, copper, lanthanum, lead and zinc due to their complexation ability [57-59], More information is required to establish the nature of the biosurfactant-metal complexes. Stability constants were established by an ion exchange resin technique [60], Cations of lowest to highest affinity for rhamnolipid were K+ < Mg + < Mn + < Ni " " < Co " < Ca2+ < Hg2+ < Fe + < Zn2+ < Cd2+ < Pb2+ < Cu2+ < M +. These affinities were approximately the same or higher than those with the organic acids, acetic, citric, fulvic and oxalic acids. This indicated the potential of the rhamnolipid for metal remediation. Molar ratios of the rhamnolipid to metal for selected metals were 2.31 for copper, 2.37 for lead, 1.91 for cadmium, 1.58 for zinc and 0.93 for nickel. Common soil cations, magnesium and potassium, had low molar ratios, 0.84 and 0.57, respectively. 

Solvolysis of Organic Ligands.— The catalysis of hydrolysis of organic esters by metal ions or complexes has been much studied for many years. Recent examples of kinetic studies include hydrolysis of oxalate esters catalysed by a variety of ions, and of the bis[-L-(-J-)-histidine methyl ester] complexes of copper(n) and of nickel(n). The relative catalytic effects of several copper(n) complexes, including Cu(imda), Cu(nta), and Cu(dien) +, on the hydrolysis of methyl glycinate have been determined. Rate constants for base hydrolysis of this ester correlate with stability constants for mixed complexes of this ester with the above-named copper(n) complexes. ... 

---