Bis(carbamoylmethylphosphine oxide) ligands fixed on the arene core via 1,2,3-triazole linkers: novel effective extractants for palladium, lanthanides and actinides

Abstract

Novel polydentate neutral organophosphorus ligands containing two diphenyl-(diethylcarbamoylmethyl)phosphine oxide moieties fixed on the arene platform via methylene-1,2,3-triazole linkers (Ar-CMPO) were synthesized by the method of “click” chemistry and studied as an extractant for Pd(II), U(VI), Th(IV) and lanthanide(III) ions from HNO₃ solutions. The influence of aqueous and organic phases on the extraction efficiency was elucidated and the stoichiometry of the complexes extracted was determined. The introduction of a 1,2,3-triazole fragment into the methylene bridge of a CMPO molecule resulted in a considerable increase in the efficiency of Pd(II) extraction. This modification of a CMPO molecule does not essentially change the extraction efficiency towards U(VI) and Ln(III) but drastically decreases the Th(IV) extraction and changes the order in the extractability of U(VI) and Th(IV) from HNO₃ solutions. Bis-CMPO ligands containing two 1,2,3-triazole moieties (Ar-CMPO) were found to possess a higher extraction efficiency towards Pd(II), U(VI), Th(IV) and lanthanide(III) ions than their mono analog 2-(diphenylphosphoryl)-N,N-diethyl-3-(1-phenyl-1H-1,2,3-triazol-4-yl)propanamide.