DIFFERENTIAL CONTRIBUTION OF METAL COMPLEXATION AND DIMERIZATION TO THE CHEMOTHERAPEUTIC POTENTIAL OF BICYCLEN-ZN-2(II) COMPLEX AGAINST HUMAN-IMMUNODEFICIENCY-VIRUS

diyl)-bis(1,4,7,10-tetraazacyclododecane)-Zn-2(II) complex (m-xylenedi yl-bicyclen-(Zn2I)-I-I), a potent inhibitor of human immunodeficiency virus (HIV), was obtained from cyclen by a combination of dimerization and metal complexation. The ratio of median cytotoxic concentration a gainst host cells (CC50) and median effective concentration against HI V cytopathogenicity (EC(50)), referred to as the selectivity index (SI ), was regarded to be a measure of anti-HIV activity. These two chemic al modifications contributed to a potent, in vitro anti-HIV activity o f m-xylenediyl-bicyclen-Zn-2(II) by respectively increasing the CC50 a nd decreasing the EC(50) in comparison with those of cyclen.