Tartaric acid metal complexes

Talspeak, 959 Talspeak process. 960 Tantalum complexes applications, 1014 Tartaric acid metal complexes geochemistry, 867 Tcchnatcs... 

In common with other hydroxy organic acids, tartaric acid complexes many metal ions. Formation constants for tartaric acid chelates with various metal ions are as follows Ca, 2.9 Cu, 3.2 Mg, 1.4 and Zn, 2.7 (68). In aqueous solution, tartaric acid can be mildly corrosive toward carbon steels, but under normal conditions it is noncorrosive to stainless steels (Table 9) (27). 

General methods for the preparation of niobium(v) and tantalum(v) complexes have been discussed and better synthetic routes to some known compounds have been described. [Nb(bpha) Cl], [Ta(bpha) Cl], and [NbO(t)3] (where bpha and t are the anions of benzoylphenylhydroxylamine and tropolone, respectively) have been prepared for the first time. NbClj or TaClj in methanol react with Hbpha to form the [M(bpha)4Cl] complexes. An aqueous solution of niobiumfv) which contains tartaric acid to prevent condensation of the hydrolysed metal species affords [NbO(t)3] with tropolone." " ... 

Antimony sulphide deposition onto metallic substrates, together with PbS and Cu-S, was first reported in the original paper of Puscher [1] using thiosulphate and antimony tartrate. No characterization of this film was carried out nor properties given. The same method was also described recently, in 1931, using a number of different metals as substrates [2], It was noted that SbCls, when mixed with thiosulphate, reacted too rapidly, hence the use of the tartrate (tartaric acid is a complexant). Again, no characterization of the films was made. 

Alkali metal complexes may be analyzed for their metal content by simple acidimetric titration. Analysis for adduct (hydroxide) content is more involved, and entails the assumption that there can be no water of hydration attached to an alcoholate anion. The method involves first, dissolving the complex in anhydrous methanol, and then, treating the resulting solution with an appropriate anhydrous add, such as tartaric acid. The acid serves to convert any hydroxide ion into water (reaction S),... 

When free (W /f. / 1 (-tartaric acid is healed above its melting point, amorphous anhydrides arc formed which, on boiling with water, regenerate the acid. Further heating causes simultaneous formation of pyruvic acid. CHiCOCOOII pyrotartaric acid. llOOrCH C HirH,lCT>OH and. linally. a black, charred residue. In common with other hydroxy organic acids, tartaric acid complexes many metal rons. 

The complex of tartaric acid and antimony (emetic) was described three centuries ago. Nevertheless, the structure of this compound has been elucidated these last fifteen years by X-ray diffraction ( 1 ). In fact, emetic presents a binuclear cyclic structure. Many authors mentioned similar complex with transition metals (vanadium (2), chromium (3)) or metalloids (arsenic (4), bismuth (5)). Emetic with phosphorus was not mentioned. Nevertheless, tartaric acid or alkyl tartrates has been utilized in phosphorus chemistry tartaric acid reacts with trialkyl phosphites giving heterocyclic phosphites (6). Starting from alkyl tartrates, we prepared spirophosphoranes with a P-H bond and sixco-ordinated compounds (7). With unprotected tartaric acid, many possibilities appear condensation as a diol, as a di(oc-hydro-xyacid), or even as a 8-hydroxyacid. 

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