Several transition metal compounds are effective antitumor drugs whose biological activity can be attributed to their ability to bind deoxyribonucleic acid (DNA). In this study, DNA-binding experiments reveal that changing one bridging ligand on compounds with the general formula Rh-2(mu-L)-(HNOCCF3)(3) alters the rate of DNA-binding by greater than 100-fold with mu-L = trifluoroacetate >> acetate > trifluoroacetamidate. These three dirhodium compounds are isolated as the major products of the reaction between Rh-2(OOCCH3)(4) and trifluoroacetamide in either refluxing chlorobenzene or molten trifluoroacetamide and have been characterized by NMR and LC/MS. By using N-15-enriched trifluoroacetamide, NMR spectroscopy was used to assign the cis-(2,1) orientations of Rh-2(mu-L)(HNOCCF3)(3) compounds where mu-L = trifluoroacetate or acetate. This is the first report of Rh-2(OOCCF3)(HNOCCF3)(3), a novel compound that may play a significant role in the biological and/or catalytic activity of compound mixtures commonly isolated as "Rh-2(HNOCCF3)(4)".