Synthesis,Spectroscopic and Structural Characterization of Homochiral Polymeric S-Malato Tungstate(VI) Complex

The S-Malic acid is a natural constituent and common metabolite of plants and animals, being involved in the Krebs cycle and in the glyoxylic acid cycle. Malic acid's metal ion chelating abilities bring about changes in the solubility of metals and influence significantly their mobilization and bioavailability in biological media. Recently, a steady flow of reports on the molecular characterization of tungsten-containing enzyme from a wide range of microorganisms has drastically changed our appreciation of tungsten. Biological tungsten is not an odd remnant of evolution but a widespread, versatile catalytic entity for the activation of the carbonyl group both in carbon dioxide and in a broad spectrum of aldehydes and carboxylic acids. The interaction of tungsten with dicarboxylic acid such as malate may provide a scaffold onto which reasonable hypotheses can be built pertaining to that metal ion's chemical speciation in biological fluids. However, scant information has been available on tungsten dicarboxylate chemistry, with equally unavailable structural data on elusive complexed forms in biological media. The lack of such data prompted us to investigate the tungsten-malate chemistry, targeting low molecular weight complexes soluble in aqueous media.