Tetrahedral, Chelated Ag I Diphosphine Complexes

Ag(I) ions have long been known to possess potent antimicrobial properties, but the use of silver compounds as pharmaceuticals has been hampered by their unfavourable chemical properties. For example, many Ag(I) complexes are light sensitive, and the insolubility of AgCl often presents problems when compounds come into contact with physiological fluids. Over 100 silver compounds have been evaluated for anticancer activity by the National Cancer Institute, and only 5 have shown at best marginal activity. The burn-treatment compound silver sulphadiazene is insoluble and applied topically to burn wounds. Its antibacterial action may be attributable to the slow release of Ag at the wound site ). 

By slowing down the rapid-ligand exchange reactions common in Ag(I) chemistry it seemed likely that a silver complex could be designed that would no be precipitated by Cr and thus might have in vivo antibacterial and anticancer activity. Bis-chelated Ag(I) diphosphine complexes appeared to be good candidates for investigation. 

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