Tartrate, formation constant

Equilibrium studies have shown that the first formation constant of the chromium(iii)-ethylenediamine system is < 10, over 10 -fold smaller than the value (10 ) previously reported. [Cr(en)3 (tn) ] (x = 0—3 and tn = tri-methylenediamine) complexes have been prepared and resolved using nitro-(-f )D-camphor. These mixed complexes have the same absolute configuration, A, as the pure [Cr(en)3] and [Cr(tn)3] species. Selective intervention of an optically active counterion in the relaxation processes of excited enantiomeric complexes can lead to partial resolution. This has been achieved for [Cr(phen)3] using D-tartrate. ... 

Reaction of disodium tartrate with silver nitrate at pH S.6 was followed by the change in the absorption spectrum at 216-250 nm. Two complex ions were proposed, Ag(C4H4Oe)- and Ag(C4H406)2, with formation constants log j8i = 2.29 and log / 2 = 4.21 respectively.266... 

Pyrolysis of the ethylene acetal of bicyclo[4.2.0]octa-4,7-diene-2,3-dione yields a-(2-hydroxyphenyl)-y-butyrolactonc 11 a mechanism involving a phenyl ketene acetal is proposed. Tartrate reacts with methanediol (formaldehyde hydrate) in alkaline solution to give an acetal-type species (9) 12 the formation constant was measured as ca 0.15 by H-NMR. Hydroxyacetal (10a) exists mainly in a boat-chair conformation (boat cycloheptanol ling), whereas the methyl derivative (10b) is chair-boat,13 as shown by 1 H-NMR, supported by molecular mechanics calculations. 

In an interesting case, the naphthalene containing sensors 48 were reported to have little or no enantioselectivity as far as the formation constants were concerned, although significant differences in both absorbance and fluorescence spectra were observed upon addition of d- and L-aspartate, glutamate, and tartrate [110], arising from enhanced preferential boat-like conformation of the selector, which induced excimer formation. When the ethoxycarbonyl units were removed (48b), this... 

Note L = hydroxyisobutyrate ion, M = metal cation, P - formation constant, IS = ionic strength, / are overall formation constants. T = tartrate for most metals, but T = lactate for the cations of Al, In, and Sc. 

Derivatives. The precise identification of a compound normally depends upon the preparation of a derivative and the determination of physical constants such as m.p. in the case of a solid. Many simple compounds can, however, be identified with a fair degree of certainty by intelligently-selected qualitative tests alone, e.g., formates, oxalates, succinates, lactates, tartrates, chloral hydrate. 

Mixed oxalate-salicylate complexes of Cd of the stoicheiometry [Cd(oxXsal)] and [Cd(ox)(sal)2] have been detected stability constants for these, [Cd-(ox) ] " (n = 1—3), and [Cd(sal) ] "" (n = 1 or 2) have also been determined. ° In oxalate solution, Hg forms the mixed complexes [Hg(C204)X ]" ( = 1, X = SCN = 1 or 2 X = OAc, NO2, Br, or tartrate). The complexation of Cd by tartrate has also been investigated. Stability constants for mixed complex formation between piperidine and a variety of zinc and cadmium mono- and dicar boxylic acids have been reported. " ... 

The formation of a 1 1 VO -citraconate complex has been identified and the stability constant determined as 2.1 x 10 1 mol by the pH titration method. Interactions between and malonate, L-tartrate, and racemic... 

The rate constants for the formation of 1 1 lanthanide-tartrate complexes have been determined by the pressure-jump technique. The values of kt range from... 

By adding thiocyanate anions, cobaltous cations Co + yield a blue complex, the tetrathiocyanocobaltate(II) complex, [Co(SCN)4]. Conversely, this reaction permits the detection of Co + by adding potassium or sodium thiocyanate. This reaction is disturbed by Fe + since the complex ([Fe(SCN)] +) it forms in the same conditions exhibits an intense red color that may mask that given by [Co(CN)4] . Hence, in order to detect Co + in the presence of Fe +, the latter must be complexed with fluoride ions (added as sodium fluoride) or with sodium and potassium tartrate. The stability constants of the complexes [Fe(SCN)] + and [FeF] + are, respectively, and K = 10 -, and that of the tartrate complex K= 10 -. This process is quite exemplary of the analytical possibilities offered by the formation of complexes. 

Greenwald I (1938) The dissociation of some calcium salts. J Biol Chem 134 437-452 Feldman I, North CA, Hunter HB (1960) Equilibrium constants for the formation of polynuclear tridentate 1 1 chelates in uranyl-malate, -citrate and tartrate systems. J Phys Chem 64 1224-1230... 

---