Spectrophotometric Study of Complex Formation between Oxovanadium(IV) and Antiamebic Drugs

Complex formation between oxovanadium(IV) and the antiamebic drugs 5, 7‐dibromo‐8‐quinolinol and 5, 7‐dichloro‐8‐quinolinol was studied in the pH 1.5–2.0 range, using ethanol, dioxane‐water, and dimethylformamide as solvents. The composition of the formed complexes was determined by more than one procedure. In ethanol and dioxane‐water, the 1:1 and 1:2 complexes were formed; in dimethylformamide, the 1:1, 1:2, and 1:3 complexes were formed. The stability constants were computed using two procedures: the molar ratio method and the extrapolation method. The reproducibility of results is satisfactory.