Preparation and physico-chemical properties of some organo-uranyl complexes

Summary Conductometric and spectrophotometric studies on the complexes of uranyl ions with 5-norvisnagin, 1-hydroxy-9-xanthenone and 8-hydroxyquinoline have been carried out in pure dioxane and dioxane-water mixture, D =30. In every case, conductometric titration shows breaks corresponding to the formation of more than one type of complex. For both 5-norvisnagin and 8-quinolinol breaks correspond to the ratios uranyl: ligand of 1:1, 1:2 and 1:4; with 1-hydroxy-9-xanthenone, the compositions 1:1 and 1:3 are identified. Spectrophotometric studies covering the visible and u.v. range indicate considerable stability of the 1:3 complex with 1-hydroxy-9-xanthenone (applying the molar ratio method). The continuous variation method establishes the existence of 1:2 uranyl complexes with both 5-norvisnagin and 8-quinolinol. Complexes precipitated from the above media at the stable compositions indicated, are spectrophotometrically scanned in the region 600–200 nm. Characteristic peaks for these complexes are observed at the same wave lengths as shown in solution. Microanalysis for carbon and uranium in the complexes separated are in fairly good agreement with the compositions proposed, especially for 5-norvisnagin and 8-hydroxyquinoline where pure crystals of the complexes could be prepared.