THERMODYNAMIC AND SPECTROSCOPIC INVESTIGATIONS ON THE INTERACTION OF URANYL(VI) WITH NEUTRAL N-DONORS AND O-DONORS IN DIMETHYL-SULFOXIDE

The thermodynamic functions Delta G circle minus, Delta H circle minus and Delta S circle minus for the formation of uranyl(VI) complexes wi th the, tridentate compound 4-azaheptane-1,7-diamine and with tetraden tate 3,6-diazaoctane-1,8-diamine and 4,7-diazadecane-1,10-diamine have been determined in anhydrous dimethyl sulfoxide (dmso) by means of po tentiometric, spectroscopic, and calorimetric measurements at 25 degre es C in a 0.1 mol dm(-3) ionic medium. The data are discussed together with those for other polyamines previously investigated. Factors affe cting the complexation of uranyl(VI) by these strongly basic ligands i n anhydrous dmso are elucidated. Spectroscopic and calorimetric eviden ce has been obtained which demonstrates that polyglycols having molecu lar frameworks similar to those of some of the polyamines do not form complexes with uranyl(VI) in this solvent.