Sodium poly- , chelation

Chelation of the divalent cation Ca to alginate chains has been studied extensively. The negative c.d. band at 205 nm for aqueous solutions of sodium poly-(L-gulopyranuronate) (called the tttt band rather than the WTT band in this early paper) loses negative intensity as Ca " is added (see Fig. 24). This change is equivalent to gaining positive c.d. intensity for a... 

A series of complexes (Chart 5) have been reported that comprise both a poly(pyrazolyl)borate ligand and an intramolecularly chelating, monoanionic coligand. These are typically obtained via halide displacement and dimer cleavage by the respective sodium or potassium poly(pyrazo-lyl)borate salt, a means by which 462—466,45 467—469,143 and 470 479144 145 were each prepared in good yield, while the related poly (pyrazolyl)methane complexes 480+— 483+ were isolated as their perchlorate salts in the presence of NaClO 145... 

The water-soluble poly- and metaphosphates exhibit chelating properties. Glassy sodium metaphosphate (DP ca 15-20) is used in water treatment for scale inhibition (16). Long-chain sodium polyphosphates (metaphosphates) are used as preservatives in red meat, poultry, and fish (16). Long-chain sodium and potassinm phosphates are added to sausage meat to improve color and texture (16). 

The chelate poly oxanes were synthesized by polycondensation in a heterogeneous system [11,13,16]. They were prepared by reaction of the chelate sodium salt (in the form of a... 

We have extended application of the Hill formalism to poly-dentate ligands, polyamines competing with tetrahydrofuran for solvation of the sodium cation (118). The Hill plots obtained are no longer linear, denoting cooperativity. Entries of the first and of the second diamine molecules into the sodium coordination shell are independent and equiprobable steps Kj = K-j and K2 X. This permits also a direct determination of the chelate effect (118). 

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