First Investigations of Complex Formation of At (l) with Phosphorous Organic Compounds

Abstract

Astatine 211 /Astatine complexes /ElectrophoresisSummary Reaction of At(I) with triphenylphosphine, triethylphosphite and tri-n-octylphosphine oxide was investigated in ethanolic solution by means of electromigration. A cationic complex with triphenylphosphine was identified being stable at pH = 1,9 in the concentration range of the ligand between c = 10" 5 to 10" 3 M. At a higher ligand concentration and at pH > 2, the reduction effect of phosphine is superimposed on the complex formation. Complex formation is confirmed by ligand exchange reactions with Br" and I". A comparatively weak complex is formed by triethylphosphite and At(I). No compound is formed by tri-noctylphosphine oxide and At (I).

Investigation of Astatine(III) Hydrolyzed Species: Experiments and Relativistic Calculations

“…Several papers have shown the formation of complexes between AtO + and simple organic and inorganic ligands. , Some structural parameters were recently determined by (quasi) relativistic quantum calculations for the complexes AtOX and AtOX 2 – , with X = Cl, SCN, and Br . It has been shown by electromigration in noncomplexing medium (H/NaClO 4 ) that AtO + reacts with water above pH 1. ,− The mobility of the species decreases when the pH increases until it equals 0 above pH 6. Milanov and co-workers proposed the formation of a neutral hydrolyzed species AtO(OH) with an apparent hydrolysis constant of 10 –1.5 M –1 (at ionic strength μ = 0.4 M) and 10 –4.1 M –1 (at μ = 0.25 M). , A constant of 10 –5.23 M –1 (μ = 0.1 M) was also proposed by Schumann et al for the pH range of 1–10 using migration data in the presence of nitrilotriacetic acid and nitroacetate .…”