Synthesis and Lanthanide Coordination Chemistry of Phosphine Oxide Decorated Dibenzothiophene and Dibenzothiophene Sulfone Platforms

Syntheses for new ligands based upon dibenzothiophene and dibenzothiophene sulfone platforms, decorated with phosphine oxide and methylphosphine oxide donor groups, are described. Coordination chemistry of 4,6-bis­(diphenylphosphinoylmethyl)­dibenzothiophene (8), 4,6-bis­(diphenylphosphinoylmethyl)­dibenzothiophene-5,5-dioxide (9) and 4,6-bis­(diphenylphosphinoyl)­dibenzothiophene-5,5-dioxide (10) with lanthanide nitrates, Ln­(NO3)3·(H2O)n is outlined, and crystal structure determinations reveal a range of chelation interactions on Ln­(III) ions. The nitric acid dependence of the solvent extraction performance of 9 and 10 in 1,2-dichloroethane for Eu­(III) and Am­(III) is described and compared against the extraction behavior of related dibenzofuran ligands (2, 3; R = Ph) and n-octyl­(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (4) measured under identical conditions.