ELSEVIER Carbohydrate Research 302 (1997) 131 - 138 CARBOHYDRATE RESEARCH Synthesis and characterization of oxovanadium(IV) complexes with saccharides Susana B. Etcheverry, Patricia A.M. Williams, Enrique J. Baran * Centro de Quimica Inorgdnica (CEQUINOR), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C. Correo 962, 1900-La Plata, Argentina Received 20 January 1997; accepted in revised form 4 April 1997 Abstract Oxovanadium(IV) complexes of the monosaccharides D-glucose and D- fructose, and the disaccharides sucrose and turanose, were obtained in aqueous solution at pH 12. Their solid sodium salts were precipitated with absolute ethanol and characterized by UV-VIS, IR, and diffuse reflectance spectroscopies. Magnetic susceptibilities at room temperature were also determined. The L:M stoichiometry, as derived from spectrophotometric titrations, was 2:1 for all saccharides except for the o-fructose complex, which was 3:1. The analytical and magnetic data also show that in the solid state the complex of this ligand shows a different behavior, generating a dinuclear species bridged by a sugar molecule, whereas all the other complexes are mononuclear. © 1997 Elsevier Science Ltd. Keywords." VO2+ complexes; Monosaccharidecomplexes; Disaccharide complexes; Electronic spectra; Vibra- tional spectra 1. Introduction Vanadium is a micronutrient element which has been shown to produce several important biological effects in living organisms [1-5]. Its deficiency causes growth retardation and skeletal deformations in ani- mals. It has also been suggested that vanadium may play a role in the regulation of (Na,K)-ATPases, phosphoryl transferases, adenylate cyclase, and pro- tein kinases, and its possible participation in hor- mone, bone, glucose, and lipid metabolism has also been discussed [1,4-6]. A number of simple and complex vanadium(IV) and vanadium(V) compounds have shown insulin-mimetic actions in animals and in different types of cultured cells [3-8]. Despite the * Corresponding author relevance of the bioactivity of vanadium derivatives, the involved mechanisms of action are poorly under- stood. In past years we have reported a number of studies that have identified and characterized complexes formed by active vanadium species with different important biomolecules. Since carbohydrates are the most abundant compounds in nature and are directly involved in several important functions like the regu- lation of metal flow through cell walls [9], we have recently initiated studies to examine the interaction of biologically relevant vanadium species with simple carbohydrates [l 0-14]. Although there are many articles dealing with the interactions of saccharides with non-transition metals, information about the interaction of carbohydrates with transition metal ions is scarce [9]. This may be 0008-6215/97/$17.00 © 1997 Elsevier Science Ltd. All rights reserved. Pll S0008-62 15(97)001 32-8