Polyoxometalates are inorganic compounds that form between oxygen and certain transition metals, most notably vanadium, molybdenum, and tungsten. Polyoxometalates have large, highly symmetric structures (Figure 1) and undergo a wide variety of chemical reactions. In addition to having industrial uses as catalysts, corrosion retardants, and indicators, polyoxometalates are known to exhibit potent antiviral, antitumoral, and, in combination with b-lactam antibiotics, antibacterial behavior. Despite their impressive anti-viral activities in cell cultures (and in studies on mice) only one polyoxometalate drug, (NH4)17Na[NaSb9W21O86] (HPA-23), has been used in clinical trials on HIV infected humans (France and US). These trials were abandoned because of the drugâs unacceptable kidney, liver, and bone marrow toxicity.
My current research projects involve modifying polyoxometalates, and improving their utility, through the attachment of specific organic/ bioorganic pendant arms to the inorganic cage (Figure 2). I plan to demonstrate that chain-like organic molecules and small protein fragments can be attached to three important classes of polyoxometalates: hexametalates, Keggin anions, and Dawson anions. If successful, these synthetic methodologies may lead to the development of new anti-HIV and anti-cancer pharmaceuticals, selective stains for electron microscopy, covalent attachment of polyoxometalates to solid supports (for catalysis), and novel, supramolecular materials. I am especially interested in using difunctional organic reagents to link two or more polyoxometalates together.