Polyhydroxy compounds, cation complexes

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 presence of basic lead acetate has been shown to affect the optical rotation of aqueous solutions of sucrose, D-glucose, and D-fructose. Frahn and Mills found that, during electrophoresis in basic lead acetate solution (pH 6.8), polyhydroxy compounds migrate as cationic complexes. 

Lead forms two series of basic salts, frequently formulated as Pb(OH)X and PbX2 2Pb(OH)2. Weinland and coworkers showed, by measurements of electrical conductivity, that, in solutions of salts of both series, a bivalent cation [(18) and (19), respectively3 was present. It is thus possible that, in the cationic complexes formed from a polyhydroxy compound and basic lead acetate, a diol grouping of the former co-ordinates... 

Angyal s group has extended its investigations on the association of polyhydroxy-compounds with cations in solution. N.m.r. spectroscopic studies showed that those cyclitols containing an ax., eg., ax. sequence of three hydroxy-groups (e.g. e/)/-inositol) form complexes with cations (e.g. Ca +, Sr +, and Ba +) addition of these divalent cations produced a downfield shift of all the proton resonances. 1 1-Complexes of c/ Z-inositol and calcium or strontium chloride... 

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