Salicylamide and salicylglycine oxidovanadium complexes with insulin-mimetic properties

Reaction of N-(2-hydroxybenzyl)-N-(2-picolyl) glycine (H(2)papy) with VOSO4 in water gives the oxidovanadium(V) oxido-bridged dimer [{(papy)(VO)}(2) mu-O)] (1). Similarly, reaction of N-(2-hydroxybenzyl) glycine (H(2)glysal) with VOSO4 gives [(glysal)VO(H2O)] (2) and reaction of salicylamide (Hsalam) with VOSO4 in methanol gives [(salam)(2)VO] (3). The crystal structure of the oxido-bridged complex 1 is reported. The insulin-mimetic activity of all three complexes was evaluated with respect to their ability to phosphorylate protein kinase B (PKB). The speciations of complexes 1 and 2 were studied over the pH range 2-10. Complex 1 shows greater stability over the whole pH range but only 2 and 3 exhibit an insulin-mimetic effect. (C) 2011 Elsevier Inc. All rights reserved.