Ion transfer of heteropolytungstate anions at the nitrobenzene vertical bar water interface and its relevance to their antiviral activities

The transfer behavior of Keggin-type heteropolytungstate anions (1,2,3-[HSi V3W9O40](6-), [PVW11O40](4-), 1,2,3- and 1,4,9-[PV3W9O40](6-), [BVW11O40](6 -), and [B12O40](5-)), across the nitrobenzene \ water interface was studie d by cyclic voltammetry. A pair of voltammetric peaks due to reversible ion transfer was observed for all the polyanions. Based on measurements of the apparent ion-transfer potentials at various pH values, ionic distribution diagrams were prepared. It was found that the apparent ion-transfer potenti als determined at pH 2.5 showed a good correlation with their antiviral act ivities. It has been suggested that the polyanion with a higher surface fie ld strength has a stronger affinity for the binding sites of viral enzymes such as reverse transcriptase and for the surface of the target cell, and t hus shows a higher inhibition activity. (C) 2001 Elsevier Science B.V. All rights reserved.