Carbohydrates alkaline earth metal complexes

Complexes of alkali metals and alkaline-earth metals with carbohydrates have been reviewed in this Series,134 and the interaction of alkaline-earth metals with maltose has been described.135 Standard procedures for the preparation of adducts of D-glucose and maltose with the hydroxides of barium, calcium, and strontium have been established. The medium most suitable for the preparation of the adduct was found to be 80% methanol. It is of interest that the composition of the adducts, from D-glucose, maltose, sucrose, and a,a-trehalose was the same, namely, 1 1, in all cases. The value of such complex-forming reactions in the recovery of metals from industrial wastes has been recognized. Metal hydroxide-sugar complexes may also play an important biological role in the transport of metal hydroxides across cell membranes. 

COMPLEXES OF ALKALI METALS AND ALKALINE-EARTH METALS WITH CARBOHYDRATES... 

Adducts prepared in aqueous media generally possess one or more molecules of water of hydration per molecule, the number being a function of cation, anion, and the combining ratio of carbohydrate to salt. Available data on complexes of simple carbohydrates indicate that three molecules of water per molecule may be the maximum for adducts of alkali metal salts as many as seven have been reported for those of the alkaline-earth metal salts. Most complexes, however, possess only one or two molecules per molecule. Generally, the higher the combining ratio, the smaller is the number of water molecules that can be accommodated by a molecule of the adduct. 

Complexes of Carbohydrate with Alkaline-earth Metal Hydroxide ... 

Rendleman, J. A., Jr., Complexes of Alkali Metals and Alkaline-earth Metals with Carbohydrates, 21, 209-271... 

Rendleman, J. a., Jr., Complexes of Alkali Metals and Alkaline-earth Metals with Carbohydrates, 21, 209 — 271 Reynolds, D. D. See Evans, W. L. Richtmyer, Nelson K., The Altrose Group of Substances, 1, 37 — 76 Richtmyer, Nelson K., The 2-(aldo-Polyhydroxyalkyl)benzimidazoles, 6, 175-203... 

Complexing of polyhydroxy compounds with alkali-metal hydroxides and acetates in nonaqueous media is a fairly general phenomenon. In addition, several carbohydrates have long been known to form crystalline addition compounds with sodium and calcium salts. Recently, Mills has provided evidence for the existence, in dilute aqueous solutions, of complexes of neutral polyhydroxy compounds with cations of the alkali metals and alkaline-earth metals. When subjected to paper electrophoresis in solutions containing the metal acetates, many compounds migrated toward the cathode (for examples, see Table I). Except for m-inositol. 

The separations at extremely high pH can only be performed in bare fused-silica capillaries, since most coatings undergo hydrolytic degradation under the highly basic conditions. The use of electrolyte systems containing alkaline-earth metals for the separation of neutral carbohydrates by CZE is mainly based on differences in the extent of complexation of the divalent metals with the carbohydrate solutes, as well as the size and shape of the molecule. These systems provided a different selectivity from that of borate buffers, although the resolution is often inferior. 

Ion chromatography can be used for the determination of ionic solutes such as inorganic anions, inorganic cations (including alkali metals, alkaline earth metals, transition metals, and rare earth metals), carboxylic, phosphonic and sulfonic acids, detergents, carbohydrates, low molecular weight organic bases, and ionic metal complexes. 

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