Polyhydroxyl complexes

Polyesters are also produced naturally in some animals. In particular, shellac is a natural product that was for many years of major commercial importance as a moulding resin (e.g. for phonograph records) and a varnish. It is a constituent of lac, which is secreted by the lac insect of S. E. Asia and exuded by it onto trees. Shellac, which is obtained by purification from lac, is a complex polyester which can be hydrolysed to polyhydroxylic acids such as 9,10,16-trihydroxyhexadecanoic acid [97],... 

Abstract In this chapter, the depression mechanism of five kinds of depressants is introduced respectively. The principle of depression by hydroxyl ion and hydrosulphide is explained which regulates the pH to make the given mineral float or not. And so the critical pH for certain minerals is determined. Thereafter, the depression by cyanide and hydrogen peroxide is narrated respectively which are that for cyanide the formation of metal cyanide complex results in depression of minerals while for hydrogen peroxide the decomposition of xanthate salts gives rise to the inhibitation of flotation. Lastly, the depression by the thio-organic such as polyhydroxyl and poly carboxylic xanthate is accounted for in detail including die flotation behavior, effect of pulp potential, adsorption mechanism and structure-property relation. 

Other evidence suggests additional complexation of borate with ferric ions and polyhydroxylated organic compounds (Antia and Cheng 1975). 

The present paper summarizes the oxidation-reduction chemistry of the gluconate complexes of Mn(II), Mn(III), and Mn(IV) in alkaline media. Electrochemical, spectrophotometric, and magnetic susceptibility measurements have been used to establish the formulas and chemical characteristics of the complexes. The oxidation-reduction chemistry for the manganese complexes formed by other ligands with polyhydroxyl functions also has been determined. 

Carbohydrate a polyhydroxyl ketone or polyhydroxyl aldehyde or a polymer composed of these. (22.6) Carboxyhemoglobin a stable complex of hemoglobin and carbon monoxide that prevents normal oxygen uptake in the blood. (20.8)... 

Although a number of the polyhydroxylated alkaloids have been reported to show anti-cancer activity, research has concentrated on developing swainsonine as a drug candidate for the management of human malignancies. Swainsonine has a complex mode of action in the whole animal. It inhibits the growth of tumour cells and prevents... 

Cyclic osmic esters have long been known to be involved in the osmium tetroxide-catalyzed cis-dihydroxylation of alkenes, but not arenes. The isolation of compound (18) by Wallis and Kochi following irradiation of the charge-transfer complex between osmium tetroxide and benzene is therefore of particular interest. This suggests that the corresponding use of catalytic quantities of osmixim tetroxide in conjunction with hydrogen peroxide could lead to the formation of polyhydroxylated cyclohexenes and -anes. 

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