Sulfate tris complexes

A similar series of solutions was prepared, using cinchonine hydrochloride (e.g., ZnS04 + cinchonine hydrochloride) instead of BCS. All solutions were 0.0214 M in zinc sulfate and 0.02 M in the alkaloid. The phen concentration was varied from zero to 0.072 M, a quantity slightly in excess of that needed to form the tris-complex. Figure 9 is a plot of the data, again. 

Ion Excha.nge, The recovery of uranium from leach solutions using ion exchange is a very important process (42). The uranium(VI) is selectively adsorbed to an anion-exchange resin as either the anionic sulfato or carbonato complexes. In carbonate solutions, the uranyl species is thought to be the tris carbonato complex, U02(C03) 3 [24646-13-7] and from sulfate solutions the anion is likely to be U02(S0 , where nis ) [56959-61-6] or 2 [27190-85-8], The uranium is eluted from the resin with a salt or acid solution of 1 AfMCl or MNO (M = H", Na", The sulfate solution is... 

Recently, novel polymethine carbonyl-dyes based on coumarin moiety and their boron difluoride complexes 9a-d and lOa-d [34—36] were evaluated as fluorescent dyes for the detection of native proteins using bovine serum albumin (BSA) as a model protein, and as probes for the nonspecific detection of proteins using a BSA/ sodium dodecyl sulfate (SDS) mixture [37]. Optical properties of these compounds in the absence and presence of BSA, as well as in SDS and BSA/SDS mixture, were measured in Tris-HCl buffer (pH 8.0) (Table 1). 

In a very special system, the photoelectrochemical regeneration of NAD(P)+ has been performed and applied to the oxidation of the model system cyclohexanol using the enzymes HLADH and TBADH. In this case, tris(2,2 -bipyridyl)ruthenium(II) is photochemically excited by visible light [43]. The excited Ru(II) complex acts as electron donor for AT,AT -dimethyl-4,4 -bipyridinium sulfate (MV2+) forming tris(2,2 -bipyridyl)ruthenium(III) and the MV-cation radical. The Ru(III) complex oxidizes NAD(P)H effectively thus... 

The [Cr(en)3]2+ and [Cr(pn)3]2+ salts have reflectance spectra (Table 11) resembling those of the hexaammines, and the six N donor atoms are assumed to complete tetragonally distorted octahedra around the metal. Stability constant measurements (Table 39) have shown that the ions [Cr(en)(aq)]2+ (vmax= 18 300 cm-1, e = 25 dm3 mol-1 cm-1) and [Cr(en)2(aq)]2+ (vma = 17 500 cm-1, e = 17 dm3 mol-1 cm-1) exist in aqueous solution, but that, as in the copper(II) system, the third ethylenediamine molecule is only weakly bound, and care is needed to prevent loss of en from tris(amine) complexes in the preparations. Several bis(amine) complexes, e.g. [CrBr2(en)2], have been isolated, and these are assigned trans structures because of IR spectral resemblances to the corresponding oopper(II) complexes. Since the spectrum of [Cr(S04)(en)2] also shows the presence of bidentate sulfate, this is assigned a trans octahedral structure with bridging anions. 

Although square-planar configuration is customarily considered classical for v/c-dioximate of nickel(II), attempts have been made repeatedly over the years for preparing the above complexes in other configurations also. By employing weakly polar solvents and some other variations, success has been claimed in the preparation of mono(dioxime) complexes of nickel(II).42,43 The dichloro-bis(l,2-cyclohexanedione dioximato)nickel(II) has been shown to have an octahedral vie structure.44 Examples of tris(dioxime) complexes of transition metals in general45"18 and of bivalent atoms40,47 in particular are rare and structural details of only a tris(dioxime) complex of cobalt(III) are known.48 In a more recent publication,49 the crystal structure of tris(l,2-cyclohexanedione dioximo)nickel(II) sulfate dihydrate has been elucidated. 

Some authors consider that the extracted complex is best formulated as an adduct, such as [(RjNH)2S04]2, U02S04(H20)3, which is the stoichiometry suggested by Sato on the basis of the analysis of solutions of tri- -octylamine saturated with uranium.204 Further studies of the extraction of uranium from sulfate media by amine salts have been reviewed by Cattrall and... 

The leaching reactions and the distribution of the various anionic uranyl species are very dependent on the pH value of the leach liquor and on the sulfate or carbonate concentration. Nominally, only the anionic di- and tri-sulfate or carbonate species will exchange with the functional groups of an anion-exchange resin, but the resin itself can facilitate the formation of complex anions in the resin phase because of the high concentration (approximately 0.5 M) of the co-ion on the functional group. Therefore, a complex equilibrium is established in which the resin is a participant the following reactions describe these equilibria for sulfuric acid leach liquors ... 

Unlike V(II), both the V(III) and V(IV) oxidation states are stable in water. However, neither the V(III) nor the V(IV) oxidation states are easily maintained in the presence of oxygen if the pH is neutral or above, although, under acidic conditions, both these states are rather easily maintained. Somewhat surprisingly, the V(IV) species is more readily oxidized by 02 than is the V(III) species. In aqueous acidic solution, the vanadium(III) ion exists as a hexaqua octahedral complex that can deprotonate to form the 2+ and 1+ species, dependent on pH. Additionally, di, tri and tetra polymeric forms are known. Structures have been proposed and their formation constants determined [10], The occurrence of the various polymeric forms in the presence of sulfate has also been described and is particularly relevant to concentration of vanadium by bioaccumulators [10],... 

Meanwhile, PPS liberated phenol in a Tris buffer solution (16). Ethanolamine works similarly and the reaction proceeded first with the expulsion of sulfate by nucleophilic attack of amine followed by liberation of phenol, presumably through the formation of a five-membered cyclic intermediate (Figure 8). Both steps of S042- and phenolate liberation were found to be catalyzed by Mg2+ ion. In Figures 9 and 10 the data are shown for the liberation of phenol. Figure 9 indicates clear rate saturation attributable to complexation in acetonit-... 

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