Metal Cations with Carbohydrates in Solution

Complexes of metal cations with carbohydrates in solution, 47, 1 -43 Courtois, Jean Emile, obituary of, 49,11 -18 Cyclomalto-oligosaccharides(cyclodextrins), inclusion complexes of, 46, 205-249 addendum to, 46, 333-335... 

Macrostructure of mucus glycoproteins in solution, 47, 345-381 Metal cations, complexes of, with carbohydrates in solution, 47, 1 -43 Molecular structure of lipid A, 50,211 -276 Monosaccharides, decomposition of, 47, 203-278... 

The literature on metal complexes of carbohydrates through 1965 has been fully reviewed by Rendleman (I), and we shall therefore only discuss recent work. We shall not discuss the complexes formed with strong bases, such as calcium and barium oxide these are salts in which the sugar acts as a weak acid, losing one or several protons. Nor shall we discuss the complexes formed with anions of oxyacids—e.g., borate, stannate, periodate, etc. ions all these are compounds formed by covalent bonds in alkaline solution. We are concerned only with complexes formed with cations in neutral aqueous solution there is no evidence for the formation of complexes between sugars and simple anions in neutral aqueous solution. (For an example of complex formation between a sugar derivative and chloride ion in chloroform solution, see Reference 3.)... 

Mobile-phase additives can also influence the relative abundance of the various adduct ions. Karlsson [105] performed post-column addition of alkali cations to enhance ESI-MS of carbohydrates and other compormds without nitrogen atoms. For most analytes, the adduct formation increased with the size of the cation. Optimum concentration of the cation in the solution was ca. 5x10 mol/1. Alkali-metal affituties and alkali-metal influence on fragmentation in MS-MS have been studied by others as well [106-107]. 

This article, therefore, deals with complexes (briefly designated as metal-sugar complexes ) that are formed, in detectable proportions, in aqueous solution from cations and un-ionized carbohydrates. As an excep- tion, we shall briefly discuss (in Section III,5) complexes of cations with aldonic and alduronic acids, because of their structural similarities to metal-sugar 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. 

Angyal SJ, Greeves D, Mills JA (1974) Complexes of carbohydrates with metal cations. 111. Conformations of alditols in aqueous solution. Aust J Chem 27 1447-1456. doi 10.1071/ CH9741447... 

Angyal SJ (1973) Shifts induced by lanthanide ions in the N.M.R. spectra of carbohydrates in aqueous solution. Carbohydr Res 26(1 ) 271-273. doi 10.1016/S0008-6215(00)85054-5 Angyal SJ (1972) Complexes of carbohydrates with metal cations. 1. Determination of the extent of complexing by N.M.R. spectroscopy. Aust J Chem 25 1957-1966. doi 10.1071/ CH9721957... 

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